treatments-xml/data/03/DA/46/03DA4645D823FFE7FF4D1D13FE30BDFD.xml

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<mods:title id="4B19362370C4D99272D4906DD50A8454">An extraordinary new fluvial bdelloid rotifer, Coronistomus impossibilis gen. nov. sp. nov., with adaptations for turbulent flow (Rotifera: Bdelloidea: Coronistomidae fam. nov.)</mods:title>
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<mods:date id="FCD1DE836A96409272E0DE63432F020A">2021</mods:date>
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<treatment id="03DA4645D823FFE7FF4D1D13FE30BDFD" ID-DOI="http://doi.org/10.5281/zenodo.4783599" ID-GBIF-Taxon="182383691" ID-Zenodo-Dep="4783599" LSID="urn:lsid:plazi:treatment:03DA4645D823FFE7FF4D1D13FE30BDFD" httpUri="http://treatment.plazi.org/id/03DA4645D823FFE7FF4D1D13FE30BDFD" lastPageId="11" lastPageNumber="27" pageId="2" pageNumber="18">
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<paragraph id="8BCCF753D823FFEEFF4D1D13FD81BC73" blockId="2.[151,571,1301,1364]" box="[151,571,1301,1328]" pageId="2" pageNumber="18">
<heading id="D084403FD823FFEEFF4D1D13FD81BC73" bold="true" box="[151,571,1301,1328]" fontSize="11" level="1" pageId="2" pageNumber="18" reason="1">
<emphasis id="B9072B41D823FFEEFF4D1D13FD81BC73" bold="true" box="[151,571,1301,1328]" pageId="2" pageNumber="18">
<taxonomicName id="4C738CD0D823FFEEFF4D1D13FE6CBC6C" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[151,470,1301,1328]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="2" pageNumber="18" phylum="Rotifera" rank="species" species="impossibilis" status="sp. nov.">
<emphasis id="B9072B41D823FFEEFF4D1D13FE6CBC6C" bold="true" box="[151,470,1301,1328]" italics="true" pageId="2" pageNumber="18">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD823FFEEFE071D13FD81BC73" box="[477,571,1301,1327]" pageId="2" pageNumber="18" rank="species">sp. nov.</taxonomicNameLabel>
</emphasis>
</heading>
</paragraph>
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<subSubSection id="C369A4D8D823FFEEFF4D1D3FFE09BC08" box="[151,435,1337,1364]" pageId="2" pageNumber="18" type="description">
<paragraph id="8BCCF753D823FFEEFF4D1D3FFE09BC08" blockId="2.[151,571,1301,1364]" box="[151,435,1337,1364]" pageId="2" pageNumber="18">
(
<figureCitation id="1348EBD6D823FFEEFF451D3FFF54BC08" box="[159,238,1337,1364]" captionStart="FIGURE 2" captionStartId="2.[151,250,1909,1933]" captionTargetBox="[193,1393,1612,1879]" captionTargetId="figure-363@2.[187,1400,1603,1885]" captionTargetPageId="2" captionText="FIGURE 2: Coronistomus impossibilis gen. nov., sp. nov., composite drawing of feeding animal from the ventral side based on photographs. Only selected features of the internal anatomy are shown." figureDoi="http://doi.org/10.5281/zenodo.4736214" httpUri="https://zenodo.org/record/4736214/files/figure.png" pageId="2" pageNumber="18">Figs. 2</figureCitation>
-6,7A,B,8A,9-11)
</paragraph>
</subSubSection>
<subSubSection id="C369A4D8D823FFEFFF4D1D87FAFCBEF1" lastPageId="3" lastPageNumber="19" pageId="2" pageNumber="18" type="materials_examined">
<paragraph id="8BCCF753D823FFEEFF4D1D87FC17BF70" blockId="2.[151,1436,1409,1580]" pageId="2" pageNumber="18">
<emphasis id="B9072B41D823FFEEFF4D1D87FF45BCC7" bold="true" box="[151,255,1409,1435]" pageId="2" pageNumber="18">Material</emphasis>
. 
<materialsCitation id="3B1BFD0ED823FFEEFED71D87FC13BF70" ID-GBIF-Occurrence="3117069301" collectionCode="ANSP" collectorName="Philadelphia, PA" country="United States of America" county="Academy of Natural Sciences" location="The" municipality="Cobb's" pageId="2" pageNumber="18" specimenCode="ANSP 2134" specimenCount="25" typeStatus="holotype">
This description was based on 
<specimenCount id="9D753CDAD823FFEEFDBF1D87FD47BCC7" box="[613,765,1409,1436]" pageId="2" pageNumber="18" type="generic">25 specimens</specimenCount>
constituting the type series. 
<location id="8EACA188D823FFEEFBE71D87FBD3BCC7" LSID="urn:lsid:plazi:treatment:03DA4645D823FFE7FF4D1D13FE30BDFD:8EACA188D823FFEEFBE71D87FBD3BCC7" box="[1085,1129,1409,1435]" country="United States of America" county="Academy of Natural Sciences" municipality="Cobb's" name="The" pageId="2" pageNumber="18">The</location>
<typeStatus id="54C849F1D823FFEEFBB51D87FB6BBCC7" box="[1135,1233,1409,1435]" pageId="2" pageNumber="18" type="holotype">holotype</typeStatus>
(
<figureCitation id="1348EBD6D823FFEEFB3B1D87FA9EBCC7" box="[1249,1316,1409,1435]" captionStart="FIGURE 3" captionStartId="3.[151,250,793,817]" captionTargetBox="[151,1435,181,769]" captionTargetId="figure-35@3.[151,1435,181,769]" captionTargetPageId="3" captionText="FIGURE 3: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype with open corona-mouth (shrunken to ~65% of live size). A, dorsal aspect. B, ventral aspect. Each image is a stack of three photographs. ca: caudal appendage; cn: corona; rm: rostrum; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736216" httpUri="https://zenodo.org/record/4736216/files/figure.png" pageId="2" pageNumber="18">Fig. 3</figureCitation>
), mounted in glycerine jelly between two cover glasses and secured in a 
<collectingMunicipality id="6BA86D29D823FFEEFC941DA3FC27BCE3" box="[846,925,1445,1471]" pageId="2" pageNumber="18">Cobb’s</collectingMunicipality>
slide holder, has been deposited in the 
<collectingCounty id="62AD8FDFD823FFEEFA821DA3FE16BCBF" pageId="2" pageNumber="18">Academy of Natural Sciences</collectingCounty>
, 
<collectorName id="26869285D823FFEEFE6C1DCFFDCEBCB8" box="[438,628,1481,1508]" pageId="2" pageNumber="18">Philadelphia, PA</collectorName>
, 
<collectingCountry id="F364B7C3D823FFEEFDA51DCFFD76BCBF" box="[639,716,1481,1507]" name="United States of America" pageId="2" pageNumber="18">U.S.A.</collectingCountry>
(
<specimenCode id="DBD55F28D823FFEEFD001DCFFCDCBCBF" box="[730,870,1481,1507]" collectionCode="ANSP" country="USA" httpUri="http://biocol.org/urn:lsid:biocol.org:col:34784" lsid="urn:lsid:biocol.org:col:34784" name="Academy of Natural Sciences of Philadelphia" pageId="2" pageNumber="18">ANSP 2134</specimenCode>
). Twelve paratypes (whole preserved specimens or extracted trophi) are in the collection of the author identified with the private morphovariant and locality designation A1HR2. All photographs in this description are those of the types
</materialsCitation>
.
</paragraph>
<caption id="DF0CA7DBD823FFEEFF4D1F73FCD3BEED" ID-DOI="http://doi.org/10.5281/zenodo.4736214" ID-Zenodo-Dep="4736214" httpUri="https://zenodo.org/record/4736214/files/figure.png" pageId="2" pageNumber="18" startId="2.[151,250,1909,1933]" targetBox="[193,1393,1612,1879]" targetPageId="2">
<paragraph id="8BCCF753D823FFEEFF4D1F73FCD3BEED" blockId="2.[151,1436,1909,1970]" pageId="2" pageNumber="18">
<emphasis id="B9072B41D823FFEEFF4D1F73FEB7BED1" bold="true" box="[151,269,1909,1933]" pageId="2" pageNumber="18">FIGURE 2</emphasis>
: 
<taxonomicName id="4C738CD0D823FFEEFEC31F70FD9CBED1" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[281,550,1909,1933]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="2" pageNumber="18" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D823FFEEFEC31F70FD9CBED1" box="[281,550,1909,1933]" italics="true" pageId="2" pageNumber="18">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD823FFEEFDF61F70FD5EBED1" box="[556,740,1910,1934]" pageId="2" pageNumber="18" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
, composite drawing of feeding animal from the ventral side based on photographs. Only selected features of the internal anatomy are shown.
</paragraph>
</caption>
<caption id="DF0CA7DBD822FFEFFF4D1B1FFE42BA25" ID-DOI="http://doi.org/10.5281/zenodo.4736216" ID-Zenodo-Dep="4736216" httpUri="https://zenodo.org/record/4736216/files/figure.png" pageId="3" pageNumber="19" startId="3.[151,250,793,817]" targetBox="[151,1435,181,769]" targetPageId="3">
<paragraph id="8BCCF753D822FFEFFF4D1B1FFE42BA25" blockId="3.[151,1437,793,890]" pageId="3" pageNumber="19">
<emphasis id="B9072B41D822FFEFFF4D1B1FFEB4BA6D" bold="true" box="[151,270,793,817]" pageId="3" pageNumber="19">FIGURE 3</emphasis>
: 
<taxonomicName id="4C738CD0D822FFEFFEC11B1CFD92BA6D" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[283,552,793,817]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="3" pageNumber="19" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D822FFEFFEC11B1CFD92BA6D" box="[283,552,793,817]" italics="true" pageId="3" pageNumber="19">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD822FFEFFDF51B1CFD50BA6D" box="[559,746,794,818]" pageId="3" pageNumber="19" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
, preserved holotype with open corona-mouth (shrunken to ~65% of live size). A, dorsal aspect. B, ventral aspect. Each image is a stack of three photographs. ca: caudal appendage; cn: corona; rm: rostrum; vmg: ventromedial gland.
</paragraph>
</caption>
<caption id="DF0CA7DBD822FFEFFF4D1EE6FB09BE40" ID-DOI="http://doi.org/10.5281/zenodo.4736218" ID-Zenodo-Dep="4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="3" pageNumber="19" startId="3.[151,250,1760,1784]" targetBox="[153,1434,913,1736]" targetPageId="3">
<paragraph id="8BCCF753D822FFEFFF4D1EE6FB09BE40" blockId="3.[151,1437,1760,1821]" pageId="3" pageNumber="19">
<emphasis id="B9072B41D822FFEFFF4D1EE6FEB6BFA4" bold="true" box="[151,268,1760,1784]" pageId="3" pageNumber="19">FIGURE 4</emphasis>
: 
<taxonomicName id="4C738CD0D822FFEFFEC31EE7FD9EBFA4" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[281,548,1760,1784]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="3" pageNumber="19" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D822FFEFFEC31EE7FD9EBFA4" box="[281,548,1760,1784]" italics="true" pageId="3" pageNumber="19">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD822FFEFFDF01EE7FD5BBFA4" box="[554,737,1761,1785]" pageId="3" pageNumber="19" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
, live specimen with corona withdrawn, slightly compressed. A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland.
</paragraph>
</caption>
<paragraph id="8BCCF753D822FFEFFF4D1F4DFAFCBEF1" blockId="3.[151,1437,1866,2037]" pageId="3" pageNumber="19">
<materialsCitation id="3B1BFD0ED822FFEFFF4D1F4DFAFBBEF1" ID-GBIF-Occurrence="3117069302" country="United States of America" county="Montgomery County" latitude="39.2122" location="An" longLatPrecision="6" longitude="-77.081" municipality="Most" pageId="3" pageNumber="19" specimenCount="1" stateProvince="Maryland" typeStatus="holotype">
<emphasis id="B9072B41D822FFEFFF4D1F4DFE97BE38" bold="true" box="[151,301,1866,1893]" pageId="3" pageNumber="19">
<typeStatus id="54C849F1D822FFEFFF4D1F4DFF6ABE39" box="[151,208,1867,1893]" pageId="3" pageNumber="19">Type</typeStatus>
locality
</emphasis>
. 
<location id="8EACA188D822FFEFFEE31F4DFEE1BE39" LSID="urn:lsid:plazi:treatment:03DA4645D823FFE7FF4D1D13FE30BDFD:8EACA188D822FFEFFEE31F4DFEE1BE39" box="[313,347,1867,1893]" country="United States of America" county="Montgomery County" latitude="39.2122" longLatPrecision="6" longitude="-77.081" municipality="Most" name="An" pageId="3" pageNumber="19" stateProvince="Maryland">An</location>
approximately 850-m stretch of the 
<location id="8EACA188D822FFEFFD361F4CFC23BE38" LSID="urn:lsid:plazi:treatment:03DA4645D823FFE7FF4D1D13FE30BDFD:8EACA188D822FFEFFD361F4CFC23BE38" box="[748,921,1866,1892]" country="United States of America" county="Montgomery County" latitude="39.2122" longLatPrecision="6" longitude="-77.081" municipality="Most" name="Hawlings River" pageId="3" pageNumber="19" stateProvince="Maryland">Hawlings River</location>
(between the spots 
<geoCoordinate id="EE479194D822FFEFFBA91F4DFB52BE39" box="[1139,1256,1867,1893]" degrees="39.2119" direction="north" orientation="latitude" pageId="3" pageNumber="19" precision="5" value="39.2119">39.2119 N</geoCoordinate>
, 
<geoCoordinate id="EE479194D822FFEFFB2E1F4CFAD4BE39" box="[1268,1390,1866,1893]" degrees="77.0846" direction="west" orientation="longitude" pageId="3" pageNumber="19" precision="5" value="-77.0846">77.0846 W</geoCoordinate>
and 
<geoCoordinate id="EE479194D822FFEFFF4D1F69FEB7BED5" box="[151,269,1903,1929]" degrees="39.2121" direction="north" orientation="latitude" pageId="3" pageNumber="19" precision="5" value="39.2121">39.2121 N</geoCoordinate>
, 
<geoCoordinate id="EE479194D822FFEFFEC21F68FE2EBED5" box="[280,404,1902,1929]" degrees="77.0760" direction="west" orientation="longitude" pageId="3" pageNumber="19" precision="5" value="-77.076">77.0760 W</geoCoordinate>
) within the 
<location id="8EACA188D822FFEFFDCD1F68FC36BED4" LSID="urn:lsid:plazi:treatment:03DA4645D823FFE7FF4D1D13FE30BDFD:8EACA188D822FFEFFDCD1F68FC36BED4" box="[535,908,1902,1929]" country="United States of America" county="Montgomery County" latitude="39.2122" longLatPrecision="6" longitude="-77.081" municipality="Most" name="Rachel Carson Conservation Park" pageId="3" pageNumber="19" stateProvince="Maryland">Rachel Carson Conservation Park</location>
, 
<collectingCounty id="62AD8FDFD822FFEFFC4D1F69FBC5BED5" box="[919,1151,1903,1929]" pageId="3" pageNumber="19">Montgomery County</collectingCounty>
, 
<collectingRegion id="49B739B1D822FFEFFB531F68FB4CBED4" box="[1161,1270,1902,1928]" country="United States of America" name="Maryland" pageId="3" pageNumber="19">Maryland</collectingRegion>
, 
<collectingCountry id="F364B7C3D822FFEFFADB1F69FA86BED5" box="[1281,1340,1903,1929]" name="United States of America" pageId="3" pageNumber="19">USA</collectingCountry>
. 
<collectingMunicipality id="6BA86D29D822FFEFFA9C1F69FAC4BED5" box="[1350,1406,1903,1929]" pageId="3" pageNumber="19">Most</collectingMunicipality>
of the specimens were from the submerged surfaces of a large rock (
<geoCoordinate id="EE479194D822FFEFFCB91F95FC60BEF1" box="[867,986,1939,1965]" degrees="39.2122" direction="north" orientation="latitude" pageId="3" pageNumber="19" precision="5" value="39.2122">39.2122 N</geoCoordinate>
, 
<geoCoordinate id="EE479194D822FFEFFC3C1F95FBDBBEF1" box="[998,1121,1939,1965]" degrees="77.0810" direction="west" orientation="longitude" pageId="3" pageNumber="19" precision="5" value="-77.081">77.0810 W</geoCoordinate>
) in the river (
<figureCitation id="1348EBD6D822FFEFFB2F1F94FA8FBEF1" box="[1269,1333,1938,1965]" captionStart="FIGURE 1" captionStartId="1.[151,250,1660,1684]" captionTargetBox="[340,1247,957,1637]" captionTargetId="figure-359@1.[340,1247,957,1637]" captionTargetPageId="1" captionText="FIGURE 1: Most of the specimens of Coronistomus impossibilis gen. nov., sp. nov. were from the submerged surfaces of the rock facing the current in the foreground (arrow), Hawlings River, 30 May 2019." figureDoi="http://doi.org/10.5281/zenodo.4736212" httpUri="https://zenodo.org/record/4736212/files/figure.png" pageId="3" pageNumber="19">Fig. 1</figureCitation>
)
</materialsCitation>
.
</paragraph>
</subSubSection>
<subSubSection id="C369A4D8D822FFEFFF1D1FB0FAD2BEA9" pageId="3" pageNumber="19" type="diagnosis">
<paragraph id="8BCCF753D822FFEFFF1D1FB0FAD2BEA9" blockId="3.[151,1437,1866,2037]" pageId="3" pageNumber="19">
<emphasis id="B9072B41D822FFEFFF1D1FB0FE80BE8C" bold="true" box="[199,314,1974,2000]" pageId="3" pageNumber="19">Diagnosis</emphasis>
. Same as for genus with pair of red cerebral eye spots, each trophi half with three major teeth interspaced with two interproximal teeth; integument papillated; body length exceeds 
<quantity id="4C8B5AB6D822FFEFFBFD1FDCFBC4BEA9" box="[1063,1150,2010,2037]" metricMagnitude="-1" metricUnit="m" metricValue="5.5" pageId="3" pageNumber="19" unit="mm" value="550.0">550 µm</quantity>
(
<figureCitation id="1348EBD6D822FFEFFB571FDCFB60BEA9" box="[1165,1242,2010,2037]" captionStart="FIGURE 2" captionStartId="2.[151,250,1909,1933]" captionTargetBox="[193,1393,1612,1879]" captionTargetId="figure-363@2.[187,1400,1603,1885]" captionTargetPageId="2" captionText="FIGURE 2: Coronistomus impossibilis gen. nov., sp. nov., composite drawing of feeding animal from the ventral side based on photographs. Only selected features of the internal anatomy are shown." figureDoi="http://doi.org/10.5281/zenodo.4736214" httpUri="https://zenodo.org/record/4736214/files/figure.png" pageId="3" pageNumber="19">Figs. 2</figureCitation>
–6,8A,9,10).
</paragraph>
</subSubSection>
<subSubSection id="C369A4D8D825FFE4FF1D1890FD64BBF5" lastPageId="8" lastPageNumber="24" pageId="4" pageNumber="20" type="etymology">
<paragraph id="8BCCF753D825FFE8FF1D1890FD44B9A4" blockId="4.[151,1437,150,537]" pageId="4" pageNumber="20">
<emphasis id="B9072B41D825FFE8FF1D1890FEF2B9EC" bold="true" box="[199,328,150,176]" pageId="4" pageNumber="20">Etymology</emphasis>
. The specific name of the new species, from Latin 
<taxonomicName id="4C738CD0D825FFE8FC5A1890FBBCB9EC" authorityName="Örstan" authorityYear="2021" box="[896,1030,150,176]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="4" pageNumber="20" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D825FFE8FC5A1890FBBCB9EC" box="[896,1030,150,176]" italics="true" pageId="4" pageNumber="20">impossibilis</emphasis>
</taxonomicName>
, was suggested by the remark of my friend and fellow rotiferologist Nataliia Iakovenko that this was “an impossible creature”, which she expressed upon seeing the photographs of the species for the first time.
</paragraph>
<paragraph id="8BCCF753D825FFE8FF1D1904FAE0BB45" blockId="4.[151,1437,150,537]" pageId="4" pageNumber="20">
<emphasis id="B9072B41D825FFE8FF1D1904FDFEB840" bold="true" box="[199,580,258,284]" pageId="4" pageNumber="20">Full description of morphology.</emphasis>
<taxonomicName id="4C738CD0D825FFE8FD971905FCCDB840" authorityName="Örstan" authorityYear="2021" box="[589,887,258,285]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="4" pageNumber="20" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D825FFE8FD971905FCCDB840" box="[589,887,258,285]" italics="true" pageId="4" pageNumber="20">Coronistomus impossibilis</emphasis>
</taxonomicName>
is a relatively large rotifer that exceeds 
<quantity id="4C8B5AB6D825FFE8FA9E1904FA26B841" box="[1348,1436,258,285]" metricMagnitude="-1" metricUnit="m" metricValue="5.5" pageId="4" pageNumber="20" unit="mm" value="550.0">550 µm</quantity>
in creeping length. During creeping the combined length of the rump plus the foot is about a third of the total body length (
<figureCitation id="1348EBD6D825FFE8FF36194CFEFFB838" box="[236,325,330,356]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="4" pageNumber="20">Fig. 4A</figureCitation>
). The lamella on the anterior dorsal rostrum forms a pair of small, semicircular lateral lappets covering tufts of short cilia that are on the ventral side. The lappets are connected medially by a narrow strip of the lamella that occasionally appears bilobed (
<figureCitation id="1348EBD6D825FFE8FDC11994FDDBB8F0" box="[539,609,402,428]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="4" pageNumber="20">Fig. 4</figureCitation>
). The antenna is slightly shorter than the lateral width of the neck and has two pseudosegments; the proximal pseudosegment covers ~3/4 of the total length of the antenna (
<figureCitation id="1348EBD6D825FFE8FB0F19B0FA95B88D" box="[1237,1327,438,465]" captionStart="FIGURE 5" captionStartId="4.[151,250,1657,1681]" captionTargetBox="[164,1423,560,1633]" captionTargetId="figure-223@4.[164,1423,560,1633]" captionTargetPageId="4" captionText="FIGURE 5: Coronistomus impossibilis gen. nov., sp. nov., eyespots and other details of live specimens.A, holotype, lateral. B, paratype, dorsal. es: eyespot; lf: longitudinal fold; lp: lappet; pp: papillae." figureDoi="http://doi.org/10.5281/zenodo.4736222" httpUri="https://zenodo.org/record/4736222/files/figure.png" pageId="4" pageNumber="20">Fig. 5A</figureCitation>
). There is a pair of red eye spots in the posterior brain. The eye spots are flat oval disks that face the anterolateral side of the brain (
<figureCitation id="1348EBD6D825FFE8FF3A19F8FE8DBB45" box="[224,311,510,537]" captionStart="FIGURE 5" captionStartId="4.[151,250,1657,1681]" captionTargetBox="[164,1423,560,1633]" captionTargetId="figure-223@4.[164,1423,560,1633]" captionTargetPageId="4" captionText="FIGURE 5: Coronistomus impossibilis gen. nov., sp. nov., eyespots and other details of live specimens.A, holotype, lateral. B, paratype, dorsal. es: eyespot; lf: longitudinal fold; lp: lappet; pp: papillae." figureDoi="http://doi.org/10.5281/zenodo.4736222" httpUri="https://zenodo.org/record/4736222/files/figure.png" pageId="4" pageNumber="20">Fig. 5A</figureCitation>
) and, as a result of their orientation, appear oblique and narrow from the dorsal side (
<figureCitation id="1348EBD6D825FFE8FB2F19F8FAF7BB45" box="[1269,1357,510,537]" captionStart="FIGURE 5" captionStartId="4.[151,250,1657,1681]" captionTargetBox="[164,1423,560,1633]" captionTargetId="figure-223@4.[164,1423,560,1633]" captionTargetPageId="4" captionText="FIGURE 5: Coronistomus impossibilis gen. nov., sp. nov., eyespots and other details of live specimens.A, holotype, lateral. B, paratype, dorsal. es: eyespot; lf: longitudinal fold; lp: lappet; pp: papillae." figureDoi="http://doi.org/10.5281/zenodo.4736222" httpUri="https://zenodo.org/record/4736222/files/figure.png" pageId="4" pageNumber="20">Fig. 5B</figureCitation>
).
</paragraph>
<caption id="DF0CA7DBD825FFE8FF4D1E7FFC3ABFE9" ID-DOI="http://doi.org/10.5281/zenodo.4736222" ID-Zenodo-Dep="4736222" httpUri="https://zenodo.org/record/4736222/files/figure.png" pageId="4" pageNumber="20" startId="4.[151,250,1657,1681]" targetBox="[164,1423,560,1633]" targetPageId="4">
<paragraph id="8BCCF753D825FFE8FF4D1E7FFC3ABFE9" blockId="4.[151,1437,1657,1718]" pageId="4" pageNumber="20">
<emphasis id="B9072B41D825FFE8FF4D1E7FFEB7BFCD" bold="true" box="[151,269,1657,1681]" pageId="4" pageNumber="20">FIGURE 5</emphasis>
: 
<taxonomicName id="4C738CD0D825FFE8FEC01E7CFD9CBFCD" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[282,550,1657,1681]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="4" pageNumber="20" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D825FFE8FEC01E7CFD9CBFCD" box="[282,550,1657,1681]" italics="true" pageId="4" pageNumber="20">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD825FFE8FDF61E7CFD5FBFCD" box="[556,741,1658,1682]" pageId="4" pageNumber="20" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
, eyespots and other details of live specimens. A, holotype, lateral. B, paratype, dorsal. es: eyespot; lf: longitudinal fold; lp: lappet; pp: papillae.
</paragraph>
</caption>
<paragraph id="8BCCF753D825FFE8FF1D1EE5FB87BE8A" blockId="4.[151,1437,1763,2006]" pageId="4" pageNumber="20">
The corona lacks pedicels and forms a weakly bilobed ciliated field on the ventral surface of the head (
<figureCitation id="1348EBD6D825FFE8FAF51EE5FAC6BFA1" box="[1327,1404,1763,1789]" captionStart="FIGURE 2" captionStartId="2.[151,250,1909,1933]" captionTargetBox="[193,1393,1612,1879]" captionTargetId="figure-363@2.[187,1400,1603,1885]" captionTargetPageId="2" captionText="FIGURE 2: Coronistomus impossibilis gen. nov., sp. nov., composite drawing of feeding animal from the ventral side based on photographs. Only selected features of the internal anatomy are shown." figureDoi="http://doi.org/10.5281/zenodo.4736214" httpUri="https://zenodo.org/record/4736214/files/figure.png" pageId="4" pageNumber="20">Figs. 2</figureCitation>
, 
<figureCitation id="1348EBD6D825FFE8FA5D1EE5FA2CBFA1" box="[1415,1430,1763,1789]" captionStart="FIGURE 3" captionStartId="3.[151,250,793,817]" captionTargetBox="[151,1435,181,769]" captionTargetId="figure-35@3.[151,1435,181,769]" captionTargetPageId="3" captionText="FIGURE 3: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype with open corona-mouth (shrunken to ~65% of live size). A, dorsal aspect. B, ventral aspect. Each image is a stack of three photographs. ca: caudal appendage; cn: corona; rm: rostrum; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736216" httpUri="https://zenodo.org/record/4736216/files/figure.png" pageId="4" pageNumber="20">3</figureCitation>
, 
<figureCitation id="1348EBD6D825FFE8FF4D1F01FF1DBE7E" box="[151,167,1799,1826]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="4" pageNumber="20">6</figureCitation>
). In 
<specimenCount id="9D753CDAD825FFE8FF001F0EFEC9BE7D" box="[218,371,1799,1826]" pageId="4" pageNumber="20" type="generic">one specimen</specimenCount>
with a total body length of 
<quantity id="4C8B5AB6D825FFE8FD7F1F01FD47BE7E" box="[677,765,1799,1826]" metricMagnitude="-1" metricUnit="m" metricValue="5.1" pageId="4" pageNumber="20" unit="mm" value="510.0">510 µm</quantity>
, the width of the open corona was 
<quantity id="4C8B5AB6D825FFE8FBA51F0EFB71BE7E" box="[1151,1227,1800,1826]" metricMagnitude="-2" metricUnit="m" metricValue="7.7" pageId="4" pageNumber="20" unit="mm" value="77.0">77 µm</quantity>
. There are roughly semicircular ridges near the anterior border of the corona (
<figureCitation id="1348EBD6D825FFE8FCFD1F2DFCC5BE1A" box="[807,895,1835,1862]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="4" pageNumber="20">Fig. 6C</figureCitation>
). The lateral borders of the corona continue into the mouth (
<figureCitation id="1348EBD6D825FFE8FEC31F49FE25BE36" box="[281,415,1871,1898]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="4" pageNumber="20">Figs. 6A, B</figureCitation>
). The open corona and the mouth are surrounded by an almost circular rim (
<figureCitation id="1348EBD6D825FFE8FADB1F49FAE6BE36" box="[1281,1372,1871,1898]" captionStart="FIGURE 7" captionStartId="5.[151,250,1917,1941]" captionTargetBox="[151,1435,1351,1894]" captionTargetId="figure-94@5.[151,1435,1351,1894]" captionTargetPageId="5" captionText="FIGURE 7: Coronistomus impossibilis gen. nov., sp. nov. compared with Adineta beysunae Örstan. A, live specimen showing the circular rim of integument surrounding the corona-mouth. B, same specimen preserved. C, A. beysunae, slightly compressed live specimen.All to the same scale. cr: circular rim; re: ring-muscle; rm: rostrum." figureDoi="http://doi.org/10.5281/zenodo.4736226" httpUri="https://zenodo.org/record/4736226/files/figure.png" pageId="4" pageNumber="20">Fig. 7A</figureCitation>
). The encircling structure within this circular rim is interpreted as a ring-muscle (
<figureCitation id="1348EBD6D825FFE8FC321F75FBF8BED2" box="[1000,1090,1907,1934]" captionStart="FIGURE 7" captionStartId="5.[151,250,1917,1941]" captionTargetBox="[151,1435,1351,1894]" captionTargetId="figure-94@5.[151,1435,1351,1894]" captionTargetPageId="5" captionText="FIGURE 7: Coronistomus impossibilis gen. nov., sp. nov. compared with Adineta beysunae Örstan. A, live specimen showing the circular rim of integument surrounding the corona-mouth. B, same specimen preserved. C, A. beysunae, slightly compressed live specimen.All to the same scale. cr: circular rim; re: ring-muscle; rm: rostrum." figureDoi="http://doi.org/10.5281/zenodo.4736226" httpUri="https://zenodo.org/record/4736226/files/figure.png" pageId="4" pageNumber="20">Fig. 7B</figureCitation>
). The curved thickening of the integument forming the anterior dorsal border of this rim is the upper lip (
<figureCitation id="1348EBD6D825FFE8FC3A1F91FB86BEEE" box="[992,1084,1943,1970]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="4" pageNumber="20">Fig. 6D</figureCitation>
). The rostrum extends over the open corona and blocks the view of the upper lip from the dorsal side (
<figureCitation id="1348EBD6D825FFE8FC751FBDFC45BE89" box="[943,1023,1979,2005]" captionStart="FIGURE 2" captionStartId="2.[151,250,1909,1933]" captionTargetBox="[193,1393,1612,1879]" captionTargetId="figure-363@2.[187,1400,1603,1885]" captionTargetPageId="2" captionText="FIGURE 2: Coronistomus impossibilis gen. nov., sp. nov., composite drawing of feeding animal from the ventral side based on photographs. Only selected features of the internal anatomy are shown." figureDoi="http://doi.org/10.5281/zenodo.4736214" httpUri="https://zenodo.org/record/4736214/files/figure.png" pageId="4" pageNumber="20">Figs. 2</figureCitation>
, 
<figureCitation id="1348EBD6D825FFE8FBD11FBAFB8ABE8A" box="[1035,1072,1980,2006]" captionStart="FIGURE 7" captionStartId="5.[151,250,1917,1941]" captionTargetBox="[151,1435,1351,1894]" captionTargetId="figure-94@5.[151,1435,1351,1894]" captionTargetPageId="5" captionText="FIGURE 7: Coronistomus impossibilis gen. nov., sp. nov. compared with Adineta beysunae Örstan. A, live specimen showing the circular rim of integument surrounding the corona-mouth. B, same specimen preserved. C, A. beysunae, slightly compressed live specimen.All to the same scale. cr: circular rim; re: ring-muscle; rm: rostrum." figureDoi="http://doi.org/10.5281/zenodo.4736226" httpUri="https://zenodo.org/record/4736226/files/figure.png" pageId="4" pageNumber="20">7A</figureCitation>
).
</paragraph>
<caption id="DF0CA7DBD824FFE9FF4D1CC8FC6ABC72" ID-DOI="http://doi.org/10.5281/zenodo.4736224" ID-Zenodo-Dep="4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="5" pageNumber="21" startId="5.[151,250,1230,1254]" targetBox="[152,1435,181,1206]" targetPageId="5">
<paragraph id="8BCCF753D824FFE9FF4D1CC8FC6ABC72" blockId="5.[151,1437,1230,1326]" pageId="5" pageNumber="21">
<emphasis id="B9072B41D824FFE9FF4D1CC8FEB4BDBA" bold="true" box="[151,270,1230,1254]" pageId="5" pageNumber="21">FIGURE 6</emphasis>
: 
<taxonomicName id="4C738CD0D824FFE9FEC61CC9FD93BDBA" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[284,553,1230,1254]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="5" pageNumber="21" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D824FFE9FEC61CC9FD93BDBA" box="[284,553,1230,1254]" italics="true" pageId="5" pageNumber="21">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD824FFE9FDEB1CC9FD51BDBA" box="[561,747,1231,1255]" pageId="5" pageNumber="21" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
, preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head. All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip.
</paragraph>
</caption>
<caption id="DF0CA7DBD824FFE9FF4D1F7BFC63BE81" ID-DOI="http://doi.org/10.5281/zenodo.4736226" ID-Zenodo-Dep="4736226" httpUri="https://zenodo.org/record/4736226/files/figure.png" pageId="5" pageNumber="21" startId="5.[151,250,1917,1941]" targetBox="[151,1435,1351,1894]" targetPageId="5">
<paragraph id="8BCCF753D824FFE9FF4D1F7BFC63BE81" blockId="5.[151,1437,1917,2014]" pageId="5" pageNumber="21">
<emphasis id="B9072B41D824FFE9FF4D1F7BFEB7BECA" bold="true" box="[151,269,1917,1942]" pageId="5" pageNumber="21">FIGURE 7</emphasis>
: 
<taxonomicName id="4C738CD0D824FFE9FEC11F78FD92BECA" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[283,552,1918,1942]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="5" pageNumber="21" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D824FFE9FEC11F78FD92BECA" box="[283,552,1918,1942]" italics="true" pageId="5" pageNumber="21">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD824FFE9FDF41F78FD5DBEC9" box="[558,743,1918,1942]" pageId="5" pageNumber="21" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
compared with 
<taxonomicName id="4C738CD0D824FFE9FC511F78FB12BECA" authority="Orstan. A" authorityName="Orstan. A" box="[907,1192,1918,1944]" class="Eurotatoria" family="Adinetidae" genus="Adineta" kingdom="Animalia" order="Bdelloidea" pageId="5" pageNumber="21" phylum="Rotifera" rank="species" species="beysunae">
<emphasis id="B9072B41D824FFE9FC511F78FB84BECA" box="[907,1086,1918,1942]" italics="true" pageId="5" pageNumber="21">Adineta beysunae</emphasis>
Örstan. A
</taxonomicName>
, live specimen showing the circular rim of integument surrounding the corona-mouth. B, same specimen preserved. C, 
<taxonomicName id="4C738CD0D824FFE9FB941FA4FB7DBEE6" box="[1102,1223,1954,1978]" class="Eurotatoria" family="Adinetidae" genus="Adineta" kingdom="Animalia" order="Bdelloidea" pageId="5" pageNumber="21" phylum="Rotifera" rank="species" species="beysunae">
<emphasis id="B9072B41D824FFE9FB941FA4FB7DBEE6" box="[1102,1223,1954,1978]" italics="true" pageId="5" pageNumber="21">A. beysunae</emphasis>
</taxonomicName>
, slightly compressed live specimen. All to the same scale. cr: circular rim; re: ring-muscle; rm: rostrum.
</paragraph>
</caption>
<paragraph id="8BCCF753D827FFEAFF1D1891FADCB839" blockId="6.[151,1436,151,357]" pageId="6" pageNumber="22">
The trophi are ramate and have semicircular continuous manubria. On each half (uncus) there are three widely spaced major teeth interspaced with two interproximal teeth and numerous minor teeth outside them (
<figureCitation id="1348EBD6D827FFEAFACF18BDFACAB989" box="[1301,1392,187,213]" captionStart="FIGURE 8" captionStartId="6.[151,250,786,810]" captionTargetBox="[151,1435,381,762]" captionTargetId="figure-134@6.[151,1435,381,762]" captionTargetPageId="6" captionText="FIGURE 8: Bdelloid trophi compared. A, Coronistomus impossibilis gen. nov., sp. nov. B, Philodina sp. C, Abrochtha sp. ipt: interproximal teeth." figureDoi="http://doi.org/10.5281/zenodo.4736228" httpUri="https://zenodo.org/record/4736228/files/figure.png" pageId="6" pageNumber="22">Fig. 8A</figureCitation>
). In 11 trophi that were examined (either extracted or in compressed specimens), there was no variation in the number of major and interproximal teeth. The trophi in 
<figureCitation id="1348EBD6D827FFEAFD5C1905FD63B841" box="[646,729,259,285]" captionStart="FIGURE 8" captionStartId="6.[151,250,786,810]" captionTargetBox="[151,1435,381,762]" captionTargetId="figure-134@6.[151,1435,381,762]" captionTargetPageId="6" captionText="FIGURE 8: Bdelloid trophi compared. A, Coronistomus impossibilis gen. nov., sp. nov. B, Philodina sp. C, Abrochtha sp. ipt: interproximal teeth." figureDoi="http://doi.org/10.5281/zenodo.4736228" httpUri="https://zenodo.org/record/4736228/files/figure.png" pageId="6" pageNumber="22">Fig. 8A</figureCitation>
had seven anterior and 12 posterior minor teeth on one half and six anterior and 13 posterior minor teeth on the other. On two sets of trophi, including the one in 
<figureCitation id="1348EBD6D827FFEAFB1D1921FAA4B81D" box="[1223,1310,295,321]" captionStart="FIGURE 8" captionStartId="6.[151,250,786,810]" captionTargetBox="[151,1435,381,762]" captionTargetId="figure-134@6.[151,1435,381,762]" captionTargetPageId="6" captionText="FIGURE 8: Bdelloid trophi compared. A, Coronistomus impossibilis gen. nov., sp. nov. B, Philodina sp. C, Abrochtha sp. ipt: interproximal teeth." figureDoi="http://doi.org/10.5281/zenodo.4736228" httpUri="https://zenodo.org/record/4736228/files/figure.png" pageId="6" pageNumber="22">Fig. 8A</figureCitation>
, one posterior minor tooth on each half appeared slightly more prominent than the others. The trophi are not protrusible.
</paragraph>
<caption id="DF0CA7DBD827FFEAFF4D1B14FEDABA12" ID-DOI="http://doi.org/10.5281/zenodo.4736228" ID-Zenodo-Dep="4736228" httpUri="https://zenodo.org/record/4736228/files/figure.png" pageId="6" pageNumber="22" startId="6.[151,250,786,810]" targetBox="[151,1435,381,762]" targetPageId="6">
<paragraph id="8BCCF753D827FFEAFF4D1B14FEDABA12" blockId="6.[151,1437,786,846]" pageId="6" pageNumber="22">
<emphasis id="B9072B41D827FFEAFF4D1B14FEB7BA76" bold="true" box="[151,269,786,810]" pageId="6" pageNumber="22">FIGURE 8</emphasis>
: Bdelloid trophi compared. A, 
<taxonomicName id="4C738CD0D827FFEAFD911B14FCEDBA76" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[587,855,786,810]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="6" pageNumber="22" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D827FFEAFD911B14FCEDBA76" box="[587,855,786,810]" italics="true" pageId="6" pageNumber="22">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD827FFEAFC841B14FBADBA75" box="[862,1047,786,810]" pageId="6" pageNumber="22" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
B, 
<taxonomicName id="4C738CD0D827FFEAFBE01B14FB61BA76" box="[1082,1243,786,810]" class="Eurotatoria" family="Philodinidae" genus="Philodina" kingdom="Animalia" order="Bdelloidea" pageId="6" pageNumber="22" phylum="Rotifera" rank="species" species="undefined-c">
<emphasis id="B9072B41D827FFEAFBE01B14FB24BA76" box="[1082,1182,786,810]" italics="true" pageId="6" pageNumber="22">Philodina</emphasis>
sp. C
</taxonomicName>
, 
<taxonomicName id="4C738CD0D827FFEAFB3C1B14FACEBA75" box="[1254,1396,786,810]" class="Eurotatoria" family="Philodinavidae" genus="Abrochtha" kingdom="Animalia" order="Bdelloidea" pageId="6" pageNumber="22" phylum="Rotifera" rank="species" species="undetermined">
<emphasis id="B9072B41D827FFEAFB3C1B14FAEABA76" box="[1254,1360,786,810]" italics="true" pageId="6" pageNumber="22">Abrochtha</emphasis>
sp.
</taxonomicName>
ipt: interproximal teeth.
</paragraph>
</caption>
<caption id="DF0CA7DBD827FFEAFF4D1F64FAB6BE9E" ID-DOI="http://doi.org/10.5281/zenodo.4736230" ID-Zenodo-Dep="4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="6" pageNumber="22" startId="6.[151,250,1890,1914]" targetBox="[151,1435,870,1866]" targetPageId="6">
<paragraph id="8BCCF753D827FFEAFF4D1F64FAB6BE9E" blockId="6.[151,1437,1890,1986]" pageId="6" pageNumber="22">
<emphasis id="B9072B41D827FFEAFF4D1F64FEB4BE26" bold="true" box="[151,270,1890,1914]" pageId="6" pageNumber="22">FIGURE 9</emphasis>
: 
<taxonomicName id="4C738CD0D827FFEAFEC61F65FD90BE26" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[284,554,1890,1914]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="6" pageNumber="22" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D827FFEAFEC61F65FD90BE26" box="[284,554,1890,1914]" italics="true" pageId="6" pageNumber="22">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD827FFEAFDEB1F65FD56BE26" box="[561,748,1891,1915]" pageId="6" pageNumber="22" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium.
</paragraph>
</caption>
<paragraph id="8BCCF753D826FFEBFF1D1891FBDBB88D" blockId="7.[151,1436,151,717]" pageId="7" pageNumber="23">
The integument all over the body is covered with small papillae that are most prominent around the trunk where the integument also forms narrowly spaced longitudinal folds (
<figureCitation id="1348EBD6D826FFEBFCBE18BDFC07B989" box="[868,957,186,213]" captionStart="FIGURE 5" captionStartId="4.[151,250,1657,1681]" captionTargetBox="[164,1423,560,1633]" captionTargetId="figure-223@4.[164,1423,560,1633]" captionTargetPageId="4" captionText="FIGURE 5: Coronistomus impossibilis gen. nov., sp. nov., eyespots and other details of live specimens.A, holotype, lateral. B, paratype, dorsal. es: eyespot; lf: longitudinal fold; lp: lappet; pp: papillae." figureDoi="http://doi.org/10.5281/zenodo.4736222" httpUri="https://zenodo.org/record/4736222/files/figure.png" pageId="7" pageNumber="23">Fig. 5B</figureCitation>
). The largest organ in the neck is the dorsotransverse gland located dorsal to the anterior stomach. This gland has two lateral lobes connected by a narrower median section over the stomach (
<figureCitation id="1348EBD6D826FFEBFDCE1905FDD7B841" box="[532,621,259,285]" captionStart="FIGURE 9" captionStartId="6.[151,250,1890,1914]" captionTargetBox="[151,1435,870,1866]" captionTargetId="figure-160@6.[151,1435,870,1866]" captionTargetPageId="6" captionText="FIGURE 9: Coronistomus impossibilis gen. nov., sp. nov. A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium." figureDoi="http://doi.org/10.5281/zenodo.4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="7" pageNumber="23">Fig. 9A</figureCitation>
). The most prominent gland on the ventral side is the ventromedial gland positioned slightly posterior to the anterior stomach. It consists of a circular posterior part and an elongated anterior part extending to the stomach entrance (
<figureCitation id="1348EBD6D826FFEBFDB9194DFD07B839" box="[611,701,331,357]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="7" pageNumber="23">Fig. 4B</figureCitation>
). The stomach has a ciliated lumen that passes into the intestine through a sphincter. There is a pair of vitellaria each with eight nuclei. Two eggs deposited by different individuals were examined: they were ellipsoid in shape and yellow-orange in color; one had smooth poles, while the other had a small nipple at one of its poles. Both eggs had bits of debris stuck on them (
<figureCitation id="1348EBD6D826FFEBFC2619B1FBEEB88D" box="[1020,1108,439,465]" captionStart="FIGURE 9" captionStartId="6.[151,250,1890,1914]" captionTargetBox="[151,1435,870,1866]" captionTargetId="figure-160@6.[151,1435,870,1866]" captionTargetPageId="6" captionText="FIGURE 9: Coronistomus impossibilis gen. nov., sp. nov. A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium." figureDoi="http://doi.org/10.5281/zenodo.4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="7" pageNumber="23">Fig. 9B</figureCitation>
).
</paragraph>
<paragraph id="8BCCF753D826FFEBFF1D19DDFE8DBB91" blockId="7.[151,1436,151,717]" pageId="7" pageNumber="23">
The rump and the foot are relatively thick (
<figureCitation id="1348EBD6D826FFEBFD6D19DDFCBDB8A9" box="[695,775,475,501]" captionStart="FIGURE 3" captionStartId="3.[151,250,793,817]" captionTargetBox="[151,1435,181,769]" captionTargetId="figure-35@3.[151,1435,181,769]" captionTargetPageId="3" captionText="FIGURE 3: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype with open corona-mouth (shrunken to ~65% of live size). A, dorsal aspect. B, ventral aspect. Each image is a stack of three photographs. ca: caudal appendage; cn: corona; rm: rostrum; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736216" httpUri="https://zenodo.org/record/4736216/files/figure.png" pageId="7" pageNumber="23">Figs. 3</figureCitation>
, 
<figureCitation id="1348EBD6D826FFEBFCCC19DDFC86B8A9" box="[790,828,475,501]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="7" pageNumber="23">4A</figureCitation>
). A slight swelling over the anal opening is often noticeable (
<figureCitation id="1348EBD6D826FFEBFEDA19F9FEE0BB45" box="[256,346,511,537]" captionStart="FIGURE 9" captionStartId="6.[151,250,1890,1914]" captionTargetBox="[151,1435,870,1866]" captionTargetId="figure-160@6.[151,1435,870,1866]" captionTargetPageId="6" captionText="FIGURE 9: Coronistomus impossibilis gen. nov., sp. nov. A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium." figureDoi="http://doi.org/10.5281/zenodo.4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="7" pageNumber="23">Fig. 9C</figureCitation>
). The transverse folds of the integument of the foot are not distinct, but there appear to be two pseudosegments prior to the one carrying the toes. There are two pairs of longitudinal gland complexes in the foot (
<figureCitation id="1348EBD6D826FFEBFF7A1A41FEB2BB3D" box="[160,264,583,609]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="7" pageNumber="23">Fig. 10A</figureCitation>
). Each dorsolateral gland complex consists of a set of five cells aligned along each side of the foot, while each ventromedial complex has one anterior elongated syncytial mass and a large posterior cell (
<figureCitation id="1348EBD6D826FFEBFB061A6DFAFFBBD9" box="[1244,1349,619,645]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="7" pageNumber="23">Fig. 10A</figureCitation>
). These gland complexes and the ducts that exit from their posterior ends take up most of the space inside the extended foot (
<figureCitation id="1348EBD6D826FFEBFF7A1AB5FE90BB91" box="[160,298,691,717]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="7" pageNumber="23">Fig. 10A, D</figureCitation>
).
</paragraph>
<caption id="DF0CA7DBD826FFEBFF4D1F13FA2CBE29" ID-DOI="http://doi.org/10.5281/zenodo.4736232" ID-Zenodo-Dep="4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="7" pageNumber="23" startId="7.[151,250,1813,1837]" targetBox="[151,1435,741,1789]" targetPageId="7">
<paragraph id="8BCCF753D826FFEBFF4D1F13FA2CBE29" blockId="7.[151,1437,1813,1909]" pageId="7" pageNumber="23">
<emphasis id="B9072B41D826FFEBFF4D1F13FEA2BE71" bold="true" box="[151,280,1813,1837]" pageId="7" pageNumber="23">FIGURE 10</emphasis>
: 
<taxonomicName id="4C738CD0D826FFEBFEFE1F10FD8ABE71" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[292,560,1813,1837]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="7" pageNumber="23" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D826FFEBFEFE1F10FD8ABE71" box="[292,560,1813,1837]" italics="true" pageId="7" pageNumber="23">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD826FFEBFDEF1F10FD51BE71" box="[565,747,1814,1838]" pageId="7" pageNumber="23" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
, details of foot anatomy. A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex.
</paragraph>
</caption>
<paragraph id="8BCCF753D826FFE4FF1D1FA2FEFCB88D" blockId="7.[151,1436,1956,2018]" lastBlockId="8.[151,1437,151,2014]" lastPageId="8" lastPageNumber="24" pageId="7" pageNumber="23">
There is a pair of long, thick ventral toes. Each toe consists of a long proximal and a shorter distal pseudosegment (
<figureCitation id="1348EBD6D826FFEBFF3A1FCEFE82BEBE" box="[224,312,1992,2018]" captionStart="FIGURE 3" captionStartId="3.[151,250,793,817]" captionTargetBox="[151,1435,181,769]" captionTargetId="figure-35@3.[151,1435,181,769]" captionTargetPageId="3" captionText="FIGURE 3: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype with open corona-mouth (shrunken to ~65% of live size). A, dorsal aspect. B, ventral aspect. Each image is a stack of three photographs. ca: caudal appendage; cn: corona; rm: rostrum; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736216" httpUri="https://zenodo.org/record/4736216/files/figure.png" pageId="7" pageNumber="23">Fig. 3B</figureCitation>
, 
<figureCitation id="1348EBD6D826FFEBFE9F1FCEFECFBEBE" box="[325,373,1992,2018]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="7" pageNumber="23">10B</figureCitation>
) and appears to have two attachment nibs at its tip. There are no paired spurs present in most bdelloid species. The foot ends with a prominent caudal appendage positioned medially and extending posteriorly (
<figureCitation id="1348EBD6D829FFE4FF4518BDFF54B989" box="[159,238,187,213]" captionStart="FIGURE 2" captionStartId="2.[151,250,1909,1933]" captionTargetBox="[193,1393,1612,1879]" captionTargetId="figure-363@2.[187,1400,1603,1885]" captionTargetPageId="2" captionText="FIGURE 2: Coronistomus impossibilis gen. nov., sp. nov., composite drawing of feeding animal from the ventral side based on photographs. Only selected features of the internal anatomy are shown." figureDoi="http://doi.org/10.5281/zenodo.4736214" httpUri="https://zenodo.org/record/4736214/files/figure.png" pageId="8" pageNumber="24">Figs. 2</figureCitation>
, 
<figureCitation id="1348EBD6D829FFE4FF2318BDFEA4B989" box="[249,286,187,213]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="8" pageNumber="24">4A</figureCitation>
, 
<figureCitation id="1348EBD6D829FFE4FEF218BDFEF1B989" box="[296,331,187,213]" captionStart="FIGURE 9" captionStartId="6.[151,250,1890,1914]" captionTargetBox="[151,1435,870,1866]" captionTargetId="figure-160@6.[151,1435,870,1866]" captionTargetPageId="6" captionText="FIGURE 9: Coronistomus impossibilis gen. nov., sp. nov. A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium." figureDoi="http://doi.org/10.5281/zenodo.4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="8" pageNumber="24">9C</figureCitation>
, 
<figureCitation id="1348EBD6D829FFE4FE8C18BDFE71B989" box="[342,459,187,213]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="8" pageNumber="24">10A, C, D</figureCitation>
). When viewed from the dorsal side, the caudal appendage presents an outline that starts from a wide base and narrows to a blunt tip (
<figureCitation id="1348EBD6D829FFE4FD4E18D9FD4AB9A5" box="[660,752,223,249]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="8" pageNumber="24">Fig. 4A</figureCitation>
), but from the lateral side the outline of the appendage has a broad posterior end (
<figureCitation id="1348EBD6D829FFE4FEA61905FE77B841" box="[380,461,259,285]" captionStart="FIGURE 9" captionStartId="6.[151,250,1890,1914]" captionTargetBox="[151,1435,870,1866]" captionTargetId="figure-160@6.[151,1435,870,1866]" captionTargetPageId="6" captionText="FIGURE 9: Coronistomus impossibilis gen. nov., sp. nov. A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium." figureDoi="http://doi.org/10.5281/zenodo.4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="8" pageNumber="24">Fig 9C</figureCitation>
). The caudal appendage has a pair of attachment nibs slightly ventral to its tip (
<figureCitation id="1348EBD6D829FFE4FAE91905FF15B81D" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="8" pageNumber="24">Fig. 10C, D</figureCitation>
). Up to six longitudinal duct-like structures can be seen inside the caudal appendage in photographs (
<figureCitation id="1348EBD6D829FFE4FAF21921FA2AB81D" box="[1320,1424,295,321]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="8" pageNumber="24">Fig. 10C</figureCitation>
). Four of these (two per attachment nib) are assumed to be ducts from the gland complexes and the remaining two are interpreted as muscle fibers inserting at the tip of the caudal appendage. Despite the presence of these muscles, the caudal appendage always remains out during crawling unlike the toes, which can be retracted into the foot as in other bdelloids.
</paragraph>
<paragraph id="8BCCF753D829FFE4FF1D19DDFD64BBF5" blockId="8.[151,1437,151,2014]" pageId="8" pageNumber="24">
In all specimens examined or photographed alive the stomach was yellow and occasionally orange (
<figureCitation id="1348EBD6D829FFE4FAE919DDFA22B8A9" box="[1331,1432,475,501]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="8" pageNumber="24">Figs. 4A</figureCitation>
, 
<figureCitation id="1348EBD6D829FFE4FF4D19F8FF1DBB45" box="[151,167,510,537]" captionStart="FIGURE 5" captionStartId="4.[151,250,1657,1681]" captionTargetBox="[164,1423,560,1633]" captionTargetId="figure-223@4.[164,1423,560,1633]" captionTargetPageId="4" captionText="FIGURE 5: Coronistomus impossibilis gen. nov., sp. nov., eyespots and other details of live specimens.A, holotype, lateral. B, paratype, dorsal. es: eyespot; lf: longitudinal fold; lp: lappet; pp: papillae." figureDoi="http://doi.org/10.5281/zenodo.4736222" httpUri="https://zenodo.org/record/4736222/files/figure.png" pageId="8" pageNumber="24">5</figureCitation>
). When the intestine was full, the material in it usually had a dark reddish color. The vitellaria were usually yellow and sometimes had orange inclusions. Developing and deposited eggs were yellow-orange (
<figureCitation id="1348EBD6D829FFE4FB741A25FB45BB61" box="[1198,1279,547,573]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="8" pageNumber="24">Figs. 4</figureCitation>
, 
<figureCitation id="1348EBD6D829FFE4FAD61A25FA8ABB61" box="[1292,1328,547,573]" captionStart="FIGURE 9" captionStartId="6.[151,250,1890,1914]" captionTargetBox="[151,1435,870,1866]" captionTargetId="figure-160@6.[151,1435,870,1866]" captionTargetPageId="6" captionText="FIGURE 9: Coronistomus impossibilis gen. nov., sp. nov. A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium." figureDoi="http://doi.org/10.5281/zenodo.4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="8" pageNumber="24">9B</figureCitation>
). In most specimens the corona was of a variable yellow color that became quite intense in a few specimens (Supplemental data). In all specimens the rostrum, brain and the foot were colorless; only in 
<specimenCount id="9D753CDAD829FFE4FC231A6DFB28BBD9" box="[1017,1170,619,645]" pageId="8" pageNumber="24" type="generic">one specimen</specimenCount>
that had an intense yellow corona, did the rostrum have a light yellow tint.
</paragraph>
</subSubSection>
<subSubSection id="C369A4D8D829FFE4FF1D1AB4FB0CBFBD" pageId="8" pageNumber="24" type="description">
<paragraph id="8BCCF753D829FFE4FF1D1AB4FEECBA49" blockId="8.[151,1437,151,2014]" pageId="8" pageNumber="24">
<emphasis id="B9072B41D829FFE4FF1D1AB4FEEBBB90" bold="true" box="[199,337,690,716]" pageId="8" pageNumber="24">Dimensions</emphasis>
. 
<typeStatus id="54C849F1D829FFE4FEB81AB5FE75BB91" box="[354,463,691,717]" pageId="8" pageNumber="24" type="holotype">Holotype</typeStatus>
: total length, 
<quantity id="4C8B5AB6D829FFE4FDB61AB4FD72BB91" box="[620,712,690,717]" metricMagnitude="-1" metricUnit="m" metricValue="5.3" pageId="8" pageNumber="24" unit="mm" value="530.0">530 µm</quantity>
; ratio of length of rump plus foot to total length, 0.29; antenna length, 
<quantity id="4C8B5AB6D829FFE4FF311AD1FE8DBBAD" box="[235,311,727,753]" metricMagnitude="-2" metricUnit="m" metricValue="3.2" pageId="8" pageNumber="24" unit="mm" value="32.0">32 µm</quantity>
; ratio of antenna length to head thickness, 0.65; caudal appendage length, 
<quantity id="4C8B5AB6D829FFE4FBAD1AD1FB79BBAD" box="[1143,1219,727,753]" metricMagnitude="-2" metricUnit="m" metricValue="3.0" pageId="8" pageNumber="24" unit="mm" value="30.0">30 µm</quantity>
; dimensions of 
<specimenCount id="9D753CDAD829FFE4FAAE1AD1FF78BA49" pageId="8" pageNumber="24" type="egg">one egg</specimenCount>
, 76 x 
<quantity id="4C8B5AB6D829FFE4FEDC1AFCFEE8BA49" box="[262,338,762,789]" metricMagnitude="-2" metricUnit="m" metricValue="5.5" pageId="8" pageNumber="24" unit="mm" value="55.0">55 µm</quantity>
.
</paragraph>
<paragraph id="8BCCF753D829FFE4FF1D1B19FAE1BA95" blockId="8.[151,1437,151,2014]" pageId="8" pageNumber="24">
Collective dimensions: total length (n = 15; undetermined ages): 
<quantity id="4C8B5AB6D829FFE4FC6B1B18FBFFBA65" box="[945,1093,798,825]" metricMagnitude="-1" metricUnit="m" metricValue="4.68" metricValueMax="5.66" metricValueMin="3.7" pageId="8" pageNumber="24" unit="mm" value="468.0" valueMax="566.0" valueMin="370.0">370–566 µm</quantity>
; three longest specimens: 
<quantity id="4C8B5AB6D829FFE4FAA81B18FF05BA01" metricMagnitude="-1" metricUnit="m" metricValue="5.3" pageId="8" pageNumber="24" unit="mm" value="530.0">530 µm</quantity>
, 
<quantity id="4C8B5AB6D829FFE4FF101B44FE9ABA01" box="[202,288,834,861]" metricMagnitude="-1" metricUnit="m" metricValue="5.33" pageId="8" pageNumber="24" unit="mm" value="533.0">533 µm</quantity>
and 
<quantity id="4C8B5AB6D829FFE4FE8F1B44FE14BA01" box="[341,430,834,861]" metricMagnitude="-1" metricUnit="m" metricValue="5.66" pageId="8" pageNumber="24" unit="mm" value="566.0">566 µm</quantity>
. Mean ratio of length of rump plus foot to total length (n = 9): 0.31. Mean ratio of inter-eye distance to brain width (n = 2): 0.42. Mean antenna length (n = 
<specimenCount id="9D753CDAD829FFE4FCBB1B61FC51BADD" box="[865,1003,871,897]" pageId="8" pageNumber="24" type="generic">4 specimens</specimenCount>
with total length&gt; 
<quantity id="4C8B5AB6D829FFE4FB1D1B60FA98BADD" box="[1223,1314,870,897]" metricMagnitude="-1" metricUnit="m" metricValue="5.0" pageId="8" pageNumber="24" unit="mm" value="500.0">500 µm</quantity>
): 
<quantity id="4C8B5AB6D829FFE4FAEC1B61FA22BADD" box="[1334,1432,871,897]" metricMagnitude="-2" metricUnit="m" metricValue="3.63" pageId="8" pageNumber="24" unit="mm" value="36.3">36.3 µm</quantity>
; mean ratio of antenna length to head thickness: 0.75. Mean caudal appendage length (n = 
<specimenCount id="9D753CDAD829FFE4FB461B8DFA92BAF9" box="[1180,1320,907,933]" pageId="8" pageNumber="24" type="generic">4 specimens</specimenCount>
with total length&gt; 
<quantity id="4C8B5AB6D829FFE4FF211BA8FEECBA95" box="[251,342,942,969]" metricMagnitude="-1" metricUnit="m" metricValue="5.0" pageId="8" pageNumber="24" unit="mm" value="500.0">500 µm</quantity>
): 
<quantity id="4C8B5AB6D829FFE4FEB01BA9FE71BA95" box="[362,459,943,969]" metricMagnitude="-2" metricUnit="m" metricValue="2.88" pageId="8" pageNumber="24" unit="mm" value="28.8">28.8 µm</quantity>
. Mean trophi length (n = 9): 
<quantity id="4C8B5AB6D829FFE4FCD51BA8FCCABA95" box="[783,880,942,969]" metricMagnitude="-2" metricUnit="m" metricValue="2.05" pageId="8" pageNumber="24" unit="mm" value="20.5">20.5 µm</quantity>
. Mean egg dimensions (n = 2): 83 x 
<quantity id="4C8B5AB6D829FFE4FAD11BA8FAEDBA95" box="[1291,1367,942,969]" metricMagnitude="-2" metricUnit="m" metricValue="5.7" pageId="8" pageNumber="24" unit="mm" value="57.0">57 µm</quantity>
.
</paragraph>
<paragraph id="8BCCF753D829FFE4FF1D1BD4FE0CBC25" blockId="8.[151,1437,151,2014]" pageId="8" pageNumber="24">
<emphasis id="B9072B41D829FFE4FF1D1BD4FD3CBAB0" bold="true" box="[199,646,978,1005]" pageId="8" pageNumber="24">Descriptions of habitat and behavior</emphasis>
. All specimens of 
<taxonomicName id="4C738CD0D829FFE4FCBA1BD5FBB3BAB1" authorityName="Örstan" authorityYear="2021" box="[864,1033,979,1005]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D829FFE4FCBA1BD5FBB3BAB1" box="[864,1033,979,1005]" italics="true" pageId="8" pageNumber="24">C. impossibilis</emphasis>
</taxonomicName>
were found in samples taken from submerged surfaces of rocks that were no more than about 
<quantity id="4C8B5AB6D829FFE4FCE21BF1FCC5BD4D" box="[824,895,1015,1041]" metricMagnitude="-1" metricUnit="m" metricValue="2.0" pageId="8" pageNumber="24" unit="cm" value="20.0">20 cm</quantity>
deep in areas of the river where the water flow was fast and turbulent (Supplemental data); several samples were in fact from rock surfaces facing upstream. The samples consisted of water and fine sediment and sometimes contained parts of aquatic moss and filamentous algae. In the vicinity of the main collection location (
<figureCitation id="1348EBD6D829FFE4FD701C65FD56BD21" box="[682,748,1123,1149]" captionStart="FIGURE 1" captionStartId="1.[151,250,1660,1684]" captionTargetBox="[340,1247,957,1637]" captionTargetId="figure-359@1.[340,1247,957,1637]" captionTargetPageId="1" captionText="FIGURE 1: Most of the specimens of Coronistomus impossibilis gen. nov., sp. nov. were from the submerged surfaces of the rock facing the current in the foreground (arrow), Hawlings River, 30 May 2019." figureDoi="http://doi.org/10.5281/zenodo.4736212" httpUri="https://zenodo.org/record/4736212/files/figure.png" pageId="8" pageNumber="24">Fig. 1</figureCitation>
), the highest flow velocity of the river was 
<quantity id="4C8B5AB6D829FFE4FB3B1C64FA8BBD21" box="[1249,1329,1122,1149]" metricMagnitude="-1" metricUnit="m" metricValue="6.5" pageId="8" pageNumber="24" unit="m" value="0.65">0.65 m</quantity>
/s in 
<date id="FFCDD193D829FFE4FAB31C65FE9EBDFD" pageId="8" pageNumber="24" value="2019-09">September 2019</date>
and the mean of the measurements taken in 
<date id="FFCDD193D829FFE4FCC31C81FC6ABDFD" box="[793,976,1159,1185]" pageId="8" pageNumber="24" value="2019-09">September 2019</date>
and 
<date id="FFCDD193D829FFE4FBDF1C81FB2FBDFD" box="[1029,1173,1159,1185]" pageId="8" pageNumber="24" value="2020-08">August 2020</date>
was 
<quantity id="4C8B5AB6D829FFE4FB151C80FA9BBDFD" box="[1231,1313,1158,1185]" metricMagnitude="-1" metricUnit="m" metricValue="5.8" pageId="8" pageNumber="24" unit="m" value="0.58">0.58 m</quantity>
/s. The collective information indicates that 
<taxonomicName id="4C738CD0D829FFE4FDCB1CADFD02BD99" authorityName="Örstan" authorityYear="2021" box="[529,696,1195,1221]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D829FFE4FDCB1CADFD02BD99" box="[529,696,1195,1221]" italics="true" pageId="8" pageNumber="24">C. impossibilis</emphasis>
</taxonomicName>
lives in the sediment that accumulates on the submerged surfaces of rocks exposed to a relatively fast flow velocity. Although the water level in the river may fluctuate depending on the amount of precipitation, there is no season when the water flow ceases. The lowest and the highest water temperatures recorded between 
<date id="FFCDD193D829FFE4FE251D11FD2DBC6D" box="[511,663,1303,1329]" pageId="8" pageNumber="24" value="2019-05-30">30 May 2019</date>
and 
<date id="FFCDD193D829FFE4FD151D11FC1CBC6D" box="[719,934,1303,1329]" pageId="8" pageNumber="24" value="2020-12-12">12 December 2020</date>
were 5.7°C on 
<date id="FFCDD193D829FFE4FB801D11FAAFBC6D" box="[1114,1301,1303,1329]" pageId="8" pageNumber="24" value="2020-02-03">3 February 2020</date>
and 21.8°C on 
<date id="FFCDD193D829FFE4FF611D3DFECABC09" box="[187,368,1339,1365]" pageId="8" pageNumber="24" value="2020-08-26">26 August 2020</date>
, respectively. These numbers constitute the approximate annual water temperature range in the habitat of 
<taxonomicName id="4C738CD0D829FFE4FED31D59FE15BC25" authorityName="Örstan" authorityYear="2021" box="[265,431,1375,1401]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D829FFE4FED31D59FE15BC25" box="[265,431,1375,1401]" italics="true" pageId="8" pageNumber="24">C. impossibilis</emphasis>
</taxonomicName>
.
</paragraph>
<paragraph id="8BCCF753D829FFE4FF1D1D85FB0CBFBD" blockId="8.[151,1437,151,2014]" pageId="8" pageNumber="24">
I never saw 
<taxonomicName id="4C738CD0D829FFE4FE961D85FE48BCC1" authorityName="Örstan" authorityYear="2021" box="[332,498,1411,1437]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D829FFE4FE961D85FE48BCC1" box="[332,498,1411,1437]" italics="true" pageId="8" pageNumber="24">C. impossibilis</emphasis>
</taxonomicName>
swim in the glass dishes into which the samples were transferred in the laboratory or in temporary aqueous mounts used for microscopic examination. On glass surfaces 
<taxonomicName id="4C738CD0D829FFE4FBE61DA1FB58BC9D" authorityName="Örstan" authorityYear="2021" box="[1084,1250,1447,1473]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D829FFE4FBE61DA1FB58BC9D" box="[1084,1250,1447,1473]" italics="true" pageId="8" pageNumber="24">C. impossibilis</emphasis>
</taxonomicName>
feeds by rapidly sweeping the surface with its corona back and forth, similar to the feeding of 
<taxonomicName id="4C738CD0D829FFE4FC271DCDFB16BCB9" box="[1021,1196,1483,1509]" class="Eurotatoria" family="Adinetidae" genus="Adineta" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="undetermined">
<emphasis id="B9072B41D829FFE4FC271DCDFBEEBCB9" box="[1021,1108,1483,1509]" italics="true" pageId="8" pageNumber="24">Adineta</emphasis>
species
</taxonomicName>
(Supplemental data). It crawls at a moderate speed in the ordinary leech-like fashion of bdelloids and often stops and explores its surroundings by moving its body around in restless, jerky movements while keeping its toes and the caudal appendage fixed on the glass. During feeding and creeping, 
<taxonomicName id="4C738CD0D829FFE4FD661E31FCD9BF0D" authorityName="Örstan" authorityYear="2021" box="[700,867,1591,1617]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D829FFE4FD661E31FCD9BF0D" box="[700,867,1591,1617]" italics="true" pageId="8" pageNumber="24">C. impossibilis</emphasis>
</taxonomicName>
uses its toes and the caudal appendage attached to the surface as a pivot and can rotate its extended body up to an angle of 90° or slightly more on either side of this pivot (
<figureCitation id="1348EBD6D829FFE4FF3A1E79FE88BFC5" box="[224,306,1663,1689]" captionStart="FIGURE 11" captionStartId="9.[151,250,1298,1322]" captionTargetBox="[151,1435,705,1275]" captionTargetId="figure-305@9.[151,1435,705,1275]" captionTargetPageId="9" captionText="FIGURE 11: Coronistomus impossibilis gen. nov., sp. nov., caudal appendage used as a pivot during crawling.A, body and and caudal appendage aligned. B, body turned 90° with respect to caudal appendage. ca: caudal appendage; rm: rostrum." figureDoi="http://doi.org/10.5281/zenodo.4736234" httpUri="https://zenodo.org/record/4736234/files/figure.png" pageId="8" pageNumber="24">Fig. 11</figureCitation>
). Individuals that detach from a surface often turn sideways and start to rapidly fold and unfold their bodies; this behavior continues for several minutes. It is not known whether they would exhibit this behavior in their natural environment where they would probably be surrounded by packed sedimentary debris.
</paragraph>
</subSubSection>
<subSubSection id="C369A4D8D829FFE7FF1D1EEDFE30BDFD" lastPageId="11" lastPageNumber="27" pageId="8" pageNumber="24" type="discussion">
<paragraph id="8BCCF753D829FFE4FF1D1EEDFC96BEE5" blockId="8.[151,1437,151,2014]" pageId="8" pageNumber="24">
<emphasis id="B9072B41D829FFE4FF1D1EEDFC9DBE59" bold="true" box="[199,807,1770,1797]" pageId="8" pageNumber="24">Remarks on taxonomic placement and morphology</emphasis>
. The presence of two belts of cilia surrounding the coronas of rotifers has been known at least since the 1870s. The belt that encircles the disks of the corona has been called either the trochus (
<bibRefCitation id="EFE28AA2D829FFE4FEB61F35FE4FBE11" author="Cubitt, C." box="[364,501,1843,1869]" pageId="8" pageNumber="24" pagination="5 - 12" refId="ref6993" refString="Cubitt, C. (1872) Remarks on the homological position of the members constituting the thecated section of the class Rotatoria. Monthly Microscopical Journal, 8, 5 - 12. https: // doi. org / 10.1111 / j. 1365 - 2818.1872. tb 02160. x" type="journal article" year="1872">Cubitt 1872</bibRefCitation>
) or the principal wreath (
<bibRefCitation id="EFE28AA2D829FFE4FCCC1F35FBA4BE11" author="Hudson, C. T. &amp; Gosse, P. H." box="[790,1054,1843,1869]" pageId="8" pageNumber="24" refId="ref7160" refString="Hudson, C. T. &amp; Gosse, P. H. (1889) The Rotifera or Wheel-animalcules. Vol. 1. Longmans, Green, and Co., London, 128 pp. https: // doi. org / 10.5962 / bhl. title. 39555" type="book" year="1889">Hudson &amp; Gosse 1889</bibRefCitation>
), while the slightly posterior belt, primarily on the ventral side of the head in bdelloids, is called either the cingulum (
<bibRefCitation id="EFE28AA2D829FFE4FB931F51FB6BBE2D" author="Cubitt, C." box="[1097,1233,1879,1905]" pageId="8" pageNumber="24" pagination="5 - 12" refId="ref6993" refString="Cubitt, C. (1872) Remarks on the homological position of the members constituting the thecated section of the class Rotatoria. Monthly Microscopical Journal, 8, 5 - 12. https: // doi. org / 10.1111 / j. 1365 - 2818.1872. tb 02160. x" type="journal article" year="1872">Cubitt 1872</bibRefCitation>
) or the secondary wreath (
<bibRefCitation id="EFE28AA2D829FFE4FF281F7DFE42BEC9" author="Hudson, C. T. &amp; Gosse, P. H." box="[242,504,1915,1941]" pageId="8" pageNumber="24" refId="ref7160" refString="Hudson, C. T. &amp; Gosse, P. H. (1889) The Rotifera or Wheel-animalcules. Vol. 1. Longmans, Green, and Co., London, 128 pp. https: // doi. org / 10.5962 / bhl. title. 39555" type="book" year="1889">Hudson &amp; Gosse 1889</bibRefCitation>
). Additionally, a finely ciliated field covers the ventral surfaces of the pedicels and extends into the buccal funnel (
<bibRefCitation id="EFE28AA2D829FFE4FE2C1F99FD3DBEE5" author="Hartog, M." box="[502,647,1951,1977]" pageId="8" pageNumber="24" pagination="1 - 560" refId="ref7046" refString="Hartog, M. (1896) Rotifers. In: Harmer, S. F. &amp; Shipley, A. E. (Eds.), The Cambridge Natural History, volume II. Macmillan &amp; Co., New York, pp. 1 - 560. https: // doi. org / 10.5962 / bhl. title. 1091" type="book chapter" year="1896">Hartog 1896</bibRefCitation>
; 
<bibRefCitation id="EFE28AA2D829FFE4FD491F99FCA5BEE5" author="Bartos, E." box="[659,799,1950,1977]" pageId="8" pageNumber="24" pagination="241 - 500" refId="ref6908" refString="Bartos, E. (1951) The Chechoslovak rotatoria of the order Bdelloidea. Vestnik Ceskoslovenske zoologicke spolecnosti, 15, 241 - 500." type="journal article" year="1951">Bartoš 1951</bibRefCitation>
).
</paragraph>
<paragraph id="8BCCF753D829FFE5FF1D1FC5FEBDBBF6" blockId="8.[151,1437,151,2014]" lastBlockId="9.[151,1437,151,682]" lastPageId="9" lastPageNumber="25" pageId="8" pageNumber="24">
The entire ventral surface of the head within the corona of 
<taxonomicName id="4C738CD0D829FFE4FC8E1FC5FC40BE81" authorityName="Örstan" authorityYear="2021" box="[852,1018,1987,2013]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="8" pageNumber="24" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D829FFE4FC8E1FC5FC40BE81" box="[852,1018,1987,2013]" italics="true" pageId="8" pageNumber="24">C. impossibilis</emphasis>
</taxonomicName>
is ciliated (
<figureCitation id="1348EBD6D829FFE4FBA11FC5FB6EBE82" box="[1147,1236,1987,2014]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="8" pageNumber="24">Fig. 6A</figureCitation>
). Because of their location, the semicircular ridges near the anterior border of the corona (
<figureCitation id="1348EBD6D828FFE5FC631891FBAAB9EE" box="[953,1040,151,178]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="9" pageNumber="25">Fig. 6C</figureCitation>
) appear to be homologous with the peripheries of the disks of the typical corona. Therefore, the cilia on them constitute the trochus. In bdelloid rotifers with the typical retractable corona, the cingulum runs around the bases of the pedicels and continues into the mouth (
<bibRefCitation id="EFE28AA2D828FFE5FF7B1905FE97B841" author="Bartos, E." box="[161,301,258,285]" pageId="9" pageNumber="25" pagination="241 - 500" refId="ref6908" refString="Bartos, E. (1951) The Chechoslovak rotatoria of the order Bdelloidea. Vestnik Ceskoslovenske zoologicke spolecnosti, 15, 241 - 500." type="journal article" year="1951">Bartoš 1951</bibRefCitation>
). Although there are no pedicels in 
<taxonomicName id="4C738CD0D828FFE5FD641905FCDFB841" authorityName="Örstan" authorityYear="2021" box="[702,869,259,285]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FD641905FCDFB841" box="[702,869,259,285]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
, the ciliated lateral borders of the corona continue posteriorly to form the buccal funnel that leads into its mouth (
<figureCitation id="1348EBD6D828FFE5FC831921FC08B81E" box="[857,946,295,322]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="9" pageNumber="25">Fig. 6B</figureCitation>
). Therefore, these ciliated lateral borders of the corona of 
<taxonomicName id="4C738CD0D828FFE5FEED194DFE5AB839" authorityName="Örstan" authorityYear="2021" box="[311,480,331,357]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FEED194DFE5AB839" box="[311,480,331,357]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
appear to be homologous with the cingulum of the species with the typical corona. Hereinafter, the anatomically united corona and mouth of 
<taxonomicName id="4C738CD0D828FFE5FCC71969FC79B8D5" authorityName="Örstan" authorityYear="2021" box="[797,963,367,393]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FCC71969FC79B8D5" box="[797,963,367,393]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
will be referred to as the corona-mouth. If my interpretation is correct, the single belt of cilia surrounding the corona-mouth of 
<taxonomicName id="4C738CD0D828FFE5FB881995FB43B8F1" authorityName="Örstan" authorityYear="2021" box="[1106,1273,403,429]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FB881995FB43B8F1" box="[1106,1273,403,429]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
represents the union of the cingulum and the trochus. When the corona-mouth of 
<taxonomicName id="4C738CD0D828FFE5FC5E19B1FB90B88D" authorityName="Örstan" authorityYear="2021" box="[900,1066,439,465]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FC5E19B1FB90B88D" box="[900,1066,439,465]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
is closed and withdrawn into the head, the integument folds over itself to create a puckered structure encircling the closed mouth as in bdelloids with the typical corona on pedicels (
<bibRefCitation id="EFE28AA2D828FFE5FE2D1A06FD33BB45" author="Orstan, A." box="[503,649,511,539]" pageId="9" pageNumber="25" pagination="611 - 620" refId="ref7693" refString="Orstan, A. (2020) Taxonomical characterization of bdelloid rotifers in the family Philodinidae. Quekett Journal of Microscopy, 43, 611 - 620." type="journal article" year="2020">Örstan 2020</bibRefCitation>
). During the opening of the corona-mouth the folds of the integument move out of the way to form the circular rim surrounding the corona-mouth (
<figureCitation id="1348EBD6D828FFE5FC351A25FBF2BB61" box="[1007,1096,547,573]" captionStart="FIGURE 7" captionStartId="5.[151,250,1917,1941]" captionTargetBox="[151,1435,1351,1894]" captionTargetId="figure-94@5.[151,1435,1351,1894]" captionTargetPageId="5" captionText="FIGURE 7: Coronistomus impossibilis gen. nov., sp. nov. compared with Adineta beysunae Örstan. A, live specimen showing the circular rim of integument surrounding the corona-mouth. B, same specimen preserved. C, A. beysunae, slightly compressed live specimen.All to the same scale. cr: circular rim; re: ring-muscle; rm: rostrum." figureDoi="http://doi.org/10.5281/zenodo.4736226" httpUri="https://zenodo.org/record/4736226/files/figure.png" pageId="9" pageNumber="25">Fig. 7A</figureCitation>
). The anterior dorsal border of this circular rim is considered to be homologous with the dorsal structure called the upper lip in species that have the corona on pedicels (
<figureCitation id="1348EBD6D828FFE5FE7C1A6DFE44BBDA" box="[422,510,619,646]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="9" pageNumber="25">Fig. 6D</figureCitation>
) and the ventral border posterior to the mouth may be referred to as the lower lip (
<figureCitation id="1348EBD6D828FFE5FF7A1A89FF40BBF6" box="[160,250,655,682]" captionStart="FIGURE 6" captionStartId="5.[151,250,1230,1254]" captionTargetBox="[152,1435,181,1206]" captionTargetId="figure-35@5.[152,1435,181,1206]" captionTargetPageId="5" captionText="FIGURE 6: Coronistomus impossibilis gen. nov., sp. nov., preserved holotype. A-E, focus series of open corona-mouth moving from ventral side towards dorsal side. F, diagrammatic representation of primary features of head.All to the same scale. cn: corona; ll: lower lip; mt: mouth; rm: rostrum; sr: semicircular ridge; ul: upper lip." figureDoi="http://doi.org/10.5281/zenodo.4736224" httpUri="https://zenodo.org/record/4736224/files/figure.png" pageId="9" pageNumber="25">Fig. 6A</figureCitation>
).
</paragraph>
<caption id="DF0CA7DBD828FFE5FF4D1D14FA89BC12" ID-DOI="http://doi.org/10.5281/zenodo.4736234" ID-Zenodo-Dep="4736234" httpUri="https://zenodo.org/record/4736234/files/figure.png" pageId="9" pageNumber="25" startId="9.[151,250,1298,1322]" targetBox="[151,1435,705,1275]" targetPageId="9">
<paragraph id="8BCCF753D828FFE5FF4D1D14FA89BC12" blockId="9.[151,1437,1298,1358]" pageId="9" pageNumber="25">
<emphasis id="B9072B41D828FFE5FF4D1D14FEADBC76" bold="true" box="[151,279,1298,1322]" pageId="9" pageNumber="25">FIGURE 11</emphasis>
: 
<taxonomicName id="4C738CD0D828FFE5FEFE1D14FD8ABC76" authority="Örstan, 2021" authorityName="Örstan" authorityYear="2021" box="[292,560,1298,1322]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis" status="gen. nov., sp. nov.">
<emphasis id="B9072B41D828FFE5FEFE1D14FD8ABC76" box="[292,560,1298,1322]" italics="true" pageId="9" pageNumber="25">Coronistomus impossibilis</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A234963AD828FFE5FDEC1D15FD54BC76" box="[566,750,1299,1323]" pageId="9" pageNumber="25" rank="species">gen. nov., sp. nov.</taxonomicNameLabel>
, caudal appendage used as a pivot during crawling. A, body and and caudal appendage aligned. B, body turned 90° with respect to caudal appendage. ca: caudal appendage; rm: rostrum.
</paragraph>
</caption>
<paragraph id="8BCCF753D828FFE5FF1D1D7BFEA0BE7E" blockId="9.[151,1437,1404,2043]" pageId="9" pageNumber="25">
For the familial placement of 
<taxonomicName id="4C738CD0D828FFE5FDCA1D7BFD0FBCCA" authorityName="Örstan" authorityYear="2021" box="[528,693,1404,1431]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FDCA1D7BFD0FBCCA" box="[528,693,1404,1431]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
, I will consider three bdelloid families whose members have stomachs with a lumen: the 
<taxonomicName id="4C738CD0D828FFE5FE451DA6FD8ABCE6" authorityName="C.G.Ehrenberg" authorityYear="1838" box="[415,560,1440,1466]" class="Eurotatoria" family="Philodinidae" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="family">Philodinidae</taxonomicName>
, 
<taxonomicName id="4C738CD0D828FFE5FDE01DA6FD0FBCE6" box="[570,693,1440,1466]" class="Eurotatoria" family="Adinetidae" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="family">Adinetidae</taxonomicName>
and 
<taxonomicName id="4C738CD0D828FFE5FD371DA6FC2FBCE6" authorityName="Harring. This" authorityYear="1913" box="[749,917,1440,1466]" class="Eurotatoria" family="Philodinavidae" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="family">Philodinavidae</taxonomicName>
. The characteristic philodinid corona consists of two retractable ciliated disks on pedicels. When open, the corona becomes the front end of the animal, while the mouth is located posterior to the corona on the ventral side of the head. In the 
<taxonomicName id="4C738CD0D828FFE5FBE01DEEFB02BF5E" box="[1082,1208,1512,1538]" class="Eurotatoria" family="Adinetidae" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="family">Adinetidae</taxonomicName>
, the corona is in the form of a flat ciliated surface covering most of the ventral head without a distinct division into halves. The adinetid corona is not retractable into the head, but it can be withdrawn into the body when the entire head is withdrawn. In comparison, the corona of 
<taxonomicName id="4C738CD0D828FFE5FE381E53FD33BF32" authorityName="Örstan" authorityYear="2021" box="[482,649,1620,1647]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FE381E53FD33BF32" box="[482,649,1620,1647]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
lacks pedicels and consists of a ciliated field on the ventral surface of the head, which is somewhat similar to the adinetid corona. A ring muscle similar to the one encircling the head of 
<taxonomicName id="4C738CD0D828FFE5FF4D1E9BFE84BFEA" authorityName="Örstan" authorityYear="2021" box="[151,318,1692,1719]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FF4D1E9BFE84BFEA" box="[151,318,1692,1719]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
(
<figureCitation id="1348EBD6D828FFE5FE941E9AFE19BFEB" box="[334,419,1692,1719]" captionStart="FIGURE 7" captionStartId="5.[151,250,1917,1941]" captionTargetBox="[151,1435,1351,1894]" captionTargetId="figure-94@5.[151,1435,1351,1894]" captionTargetPageId="5" captionText="FIGURE 7: Coronistomus impossibilis gen. nov., sp. nov. compared with Adineta beysunae Örstan. A, live specimen showing the circular rim of integument surrounding the corona-mouth. B, same specimen preserved. C, A. beysunae, slightly compressed live specimen.All to the same scale. cr: circular rim; re: ring-muscle; rm: rostrum." figureDoi="http://doi.org/10.5281/zenodo.4736226" httpUri="https://zenodo.org/record/4736226/files/figure.png" pageId="9" pageNumber="25">Fig. 7B</figureCitation>
) is also present in the head of 
<taxonomicName id="4C738CD0D828FFE5FD211E9AFCE8BFEA" authorityName="C.T.Hudson &amp; P.H.Gosse" authorityYear="1886" box="[763,850,1692,1718]" class="Eurotatoria" family="Adinetidae" genus="Adineta" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FD211E9AFCE8BFEA" box="[763,850,1692,1718]" italics="true" pageId="9" pageNumber="25">Adineta</emphasis>
</taxonomicName>
(
<bibRefCitation id="EFE28AA2D828FFE5FCBB1E9AFBF8BFEA" author="Leasi, F. &amp; Ricci, C." box="[865,1090,1692,1718]" pageId="9" pageNumber="25" pagination="33 - 39" refId="ref7292" refString="Leasi, F. &amp; Ricci, C. (2010) Musculature of two bdelloid rotifers, Adineta ricciae and Macrotrachela quadricornifera: organization in a functional and evolutionary perspective. Journal of Zoological Systematics and Evolutionary Research, 48, 33 - 39. https: // doi. org / 10.1111 / j. 1439 - 0469.2009.00538. x" type="journal article" year="2010">Leasi &amp; Ricci 2010</bibRefCitation>
; 
<figureCitation id="1348EBD6D828FFE5FB971E9AFB1FBFEA" box="[1101,1189,1692,1718]" captionStart="FIGURE 7" captionStartId="5.[151,250,1917,1941]" captionTargetBox="[151,1435,1351,1894]" captionTargetId="figure-94@5.[151,1435,1351,1894]" captionTargetPageId="5" captionText="FIGURE 7: Coronistomus impossibilis gen. nov., sp. nov. compared with Adineta beysunae Örstan. A, live specimen showing the circular rim of integument surrounding the corona-mouth. B, same specimen preserved. C, A. beysunae, slightly compressed live specimen.All to the same scale. cr: circular rim; re: ring-muscle; rm: rostrum." figureDoi="http://doi.org/10.5281/zenodo.4736226" httpUri="https://zenodo.org/record/4736226/files/figure.png" pageId="9" pageNumber="25">Fig. 7C</figureCitation>
). However, unlike the adinetid corona, the corona of 
<taxonomicName id="4C738CD0D828FFE5FE2F1EC7FD27BF86" authorityName="Örstan" authorityYear="2021" box="[501,669,1728,1755]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FE2F1EC7FD27BF86" box="[501,669,1728,1755]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
is clearly, if weakly, divided into two halves and is retractable into the head (
<figureCitation id="1348EBD6D828FFE5FEDE1EE2FEF3BFA2" box="[260,329,1764,1790]" captionStart="FIGURE 4" captionStartId="3.[151,250,1760,1784]" captionTargetBox="[153,1434,913,1736]" captionTargetId="figure-85@3.[153,1434,913,1736]" captionTargetPageId="3" captionText="FIGURE 4: Coronistomus impossibilis gen. nov., sp. nov., live specimen with corona withdrawn, slightly compressed.A, entire animal crawling. B, details of anterior body. ca: caudal appendage; lp: lappet; vmg: ventromedial gland." figureDoi="http://doi.org/10.5281/zenodo.4736218" httpUri="https://zenodo.org/record/4736218/files/figure.png" pageId="9" pageNumber="25">Fig. 4</figureCitation>
). These dissimilarities preclude the placement of 
<taxonomicName id="4C738CD0D828FFE5FCA81EE3FBA3BFA2" authorityName="Örstan" authorityYear="2021" box="[882,1049,1764,1791]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FCA81EE3FBA3BFA2" box="[882,1049,1764,1791]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
either in the 
<taxonomicName id="4C738CD0D828FFE5FB711EE2FA83BFA2" authorityName="C.G.Ehrenberg" authorityYear="1838" box="[1195,1337,1764,1790]" class="Eurotatoria" family="Philodinidae" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="family">Philodinidae</taxonomicName>
or in the 
<taxonomicName id="4C738CD0D828FFE5FF4D1F0EFEACBE7E" box="[151,278,1800,1826]" class="Eurotatoria" family="Adinetidae" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="family">Adinetidae</taxonomicName>
.
</paragraph>
<paragraph id="8BCCF753D828FFE6FF1D1F2AFD30B839" blockId="9.[151,1437,1404,2043]" lastBlockId="10.[151,1437,151,2013]" lastPageId="10" lastPageNumber="26" pageId="9" pageNumber="25">
The only other family that may accommodate 
<taxonomicName id="4C738CD0D828FFE5FD081F2BFCC3BE1A" authorityName="Örstan" authorityYear="2021" box="[722,889,1836,1863]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FD081F2BFCC3BE1A" box="[722,889,1836,1863]" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
is the 
<taxonomicName id="4C738CD0D828FFE5FC1F1F2AFBCABE1A" authorityName="Harring. This" authorityYear="1913" box="[965,1136,1836,1862]" class="Eurotatoria" family="Philodinavidae" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="family">Philodinavidae</taxonomicName>
, which has so far included nine species in three genera: 
<taxonomicName id="4C738CD0D828FFE5FE381F56FDEDBE36" authorityName="Bryce" authorityYear="1910" box="[482,599,1872,1898]" class="Eurotatoria" family="Philodinavidae" genus="Abrochtha" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FE381F56FDEDBE36" box="[482,599,1872,1898]" italics="true" pageId="9" pageNumber="25">Abrochtha</emphasis>
</taxonomicName>
, 
<taxonomicName id="4C738CD0D828FFE5FDBD1F57FD65BE36" authorityName="Milne" authorityYear="1916" box="[615,735,1873,1898]" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FDBD1F57FD65BE36" box="[615,735,1873,1898]" italics="true" pageId="9" pageNumber="25">Henoceros</emphasis>
</taxonomicName>
and 
<taxonomicName id="4C738CD0D828FFE5FCC21F56FC16BE36" authorityName="Harring" authorityYear="1913" box="[792,940,1872,1898]" class="Eurotatoria" family="Philodinavidae" genus="Philodinavus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FCC21F56FC16BE36" box="[792,940,1872,1898]" italics="true" pageId="9" pageNumber="25">Philodinavus</emphasis>
</taxonomicName>
. Among the characteristics of these species are their modified coronas. In 
<taxonomicName id="4C738CD0D828FFE5FE371F72FDD8BED2" authorityName="Bryce" authorityYear="1910" box="[493,610,1908,1934]" class="Eurotatoria" family="Philodinavidae" genus="Abrochtha" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FE371F72FDD8BED2" box="[493,610,1908,1934]" italics="true" pageId="9" pageNumber="25">Abrochtha</emphasis>
</taxonomicName>
small pedicels support a U-shaped trochus posterior to which lateral ciliated ridges forming the cinculum lead into the mouth (
<bibRefCitation id="EFE28AA2D828FFE5FCDA1F9EFC41BEEF" author="Melone, G. &amp; Ricci, C." box="[768,1019,1944,1971]" pageId="9" pageNumber="25" pagination="91 - 98" refId="ref7453" refString="Melone, G. &amp; Ricci, C. (1995) Rotatory apparatus in bdelloids. Hydrobiologia, 313 / 314, 91 - 98. https: // doi. org / 10.1007 / BF 00025935" type="journal article" year="1995">Melone &amp; Ricci 1995</bibRefCitation>
). In 
<taxonomicName id="4C738CD0D828FFE5FBF41F9FFB1CBEEE" authorityName="Milne" authorityYear="1916" box="[1070,1190,1945,1970]" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FBF41F9FFB1CBEEE" box="[1070,1190,1945,1970]" italics="true" pageId="9" pageNumber="25">Henoceros</emphasis>
</taxonomicName>
and 
<taxonomicName id="4C738CD0D828FFE5FB051F9EFAC9BEEE" authorityName="Harring" authorityYear="1913" box="[1247,1395,1944,1970]" class="Eurotatoria" family="Philodinavidae" genus="Philodinavus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FB051F9EFAC9BEEE" box="[1247,1395,1944,1970]" italics="true" pageId="9" pageNumber="25">Philodinavus</emphasis>
</taxonomicName>
the corona consists of a very small ciliary field without pedicels. The ciliary field comprising the corona of 
<taxonomicName id="4C738CD0D828FFE5FAF51FBBFF60BEA6" authorityName="Örstan" authorityYear="2021" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D828FFE5FAF51FBBFF60BEA6" italics="true" pageId="9" pageNumber="25">C. impossibilis</emphasis>
</taxonomicName>
also lacks pedicels but is much larger than the coronas of 
<taxonomicName id="4C738CD0D828FFE5FC801FE7FC68BEA6" authorityName="Milne" authorityYear="1916" box="[858,978,2017,2042]" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FC801FE7FC68BEA6" box="[858,978,2017,2042]" italics="true" pageId="9" pageNumber="25">Henoceros</emphasis>
</taxonomicName>
and 
<taxonomicName id="4C738CD0D828FFE5FBDC1FE6FB20BEA6" authorityName="Harring" authorityYear="1913" box="[1030,1178,2016,2042]" class="Eurotatoria" family="Philodinavidae" genus="Philodinavus" kingdom="Animalia" order="Bdelloidea" pageId="9" pageNumber="25" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D828FFE5FBDC1FE6FB20BEA6" box="[1030,1178,2016,2042]" italics="true" pageId="9" pageNumber="25">Philodinavus</emphasis>
</taxonomicName>
. Another characteristic of the philodinavid species is their protrusible trophi on which the major teeth are crowded in the anterior half and there is no anterior connection between the manubrium and the ramus (
<figureCitation id="1348EBD6D82BFFE6FC6918BDFBB1B989" box="[947,1035,187,213]" captionStart="FIGURE 8" captionStartId="6.[151,250,786,810]" captionTargetBox="[151,1435,381,762]" captionTargetId="figure-134@6.[151,1435,381,762]" captionTargetPageId="6" captionText="FIGURE 8: Bdelloid trophi compared. A, Coronistomus impossibilis gen. nov., sp. nov. B, Philodina sp. C, Abrochtha sp. ipt: interproximal teeth." figureDoi="http://doi.org/10.5281/zenodo.4736228" httpUri="https://zenodo.org/record/4736228/files/figure.png" pageId="10" pageNumber="26">Fig. 8C</figureCitation>
). In contrast, the morphology of the trophi of 
<taxonomicName id="4C738CD0D82BFFE6FED818D9FE10B9A5" authorityName="Örstan" authorityYear="2021" box="[258,426,223,249]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FED818D9FE10B9A5" box="[258,426,223,249]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
(
<figureCitation id="1348EBD6D82BFFE6FE6118D9FDAEB9A5" box="[443,532,223,249]" captionStart="FIGURE 8" captionStartId="6.[151,250,786,810]" captionTargetBox="[151,1435,381,762]" captionTargetId="figure-134@6.[151,1435,381,762]" captionTargetPageId="6" captionText="FIGURE 8: Bdelloid trophi compared. A, Coronistomus impossibilis gen. nov., sp. nov. B, Philodina sp. C, Abrochtha sp. ipt: interproximal teeth." figureDoi="http://doi.org/10.5281/zenodo.4736228" httpUri="https://zenodo.org/record/4736228/files/figure.png" pageId="10" pageNumber="26">Fig. 8A</figureCitation>
) is more like that of the trophi of non-philodinavid species with more centrally located major teeth and semicircular manubria except that the gaps between the major teeth are wider and the interproximal teeth are more distinct (
<figureCitation id="1348EBD6D82BFFE6FDC81921FDD3B81D" box="[530,617,295,321]" captionStart="FIGURE 8" captionStartId="6.[151,250,786,810]" captionTargetBox="[151,1435,381,762]" captionTargetId="figure-134@6.[151,1435,381,762]" captionTargetPageId="6" captionText="FIGURE 8: Bdelloid trophi compared. A, Coronistomus impossibilis gen. nov., sp. nov. B, Philodina sp. C, Abrochtha sp. ipt: interproximal teeth." figureDoi="http://doi.org/10.5281/zenodo.4736228" httpUri="https://zenodo.org/record/4736228/files/figure.png" pageId="10" pageNumber="26">Fig. 8B</figureCitation>
). Moreover, the videos of feeding 
<taxonomicName id="4C738CD0D82BFFE6FC2E1921FB26B81D" authorityName="Örstan" authorityYear="2021" box="[1012,1180,295,321]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FC2E1921FB26B81D" box="[1012,1180,295,321]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
do not show its trophi approaching the mouth (Supplemental data).
</paragraph>
<paragraph id="8BCCF753D82BFFE6FF1D1969FB97BB91" blockId="10.[151,1437,151,2013]" pageId="10" pageNumber="26">
A caudal appendage similar to that of 
<taxonomicName id="4C738CD0D82BFFE6FDA51969FC92B8D5" authorityName="Örstan" authorityYear="2021" box="[639,808,367,393]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FDA51969FC92B8D5" box="[639,808,367,393]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
is also present in the two species of the genus 
<taxonomicName id="4C738CD0D82BFFE6FA901969FF7CB8F0" authorityName="Milne" authorityYear="1916" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D82BFFE6FA901969FF7CB8F0" italics="true" pageId="10" pageNumber="26">Henoceros</emphasis>
</taxonomicName>
, which also lack paired spurs. In his description of the first 
<taxonomicName id="4C738CD0D82BFFE6FCBC1995FB8CB8F1" box="[870,1078,403,429]" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="undetermined">
<emphasis id="B9072B41D82BFFE6FCBC1995FC64B8F0" box="[870,990,403,428]" italics="true" pageId="10" pageNumber="26">Henoceros</emphasis>
species
</taxonomicName>
(as 
<taxonomicName id="4C738CD0D82BFFE6FBBF1995FAF8B8F1" authorityName="Milne" authorityYear="1916" box="[1125,1346,403,429]" family="Acanthuridae" genus="Monoceros" higherTaxonomySource="CoL" kingdom="Animalia" order="Perciformes" pageId="10" pageNumber="26" phylum="Chordata" rank="species" species="falcatus">
<emphasis id="B9072B41D82BFFE6FBBF1995FAF8B8F1" box="[1125,1346,403,429]" italics="true" pageId="10" pageNumber="26">Monoceros falcatus</emphasis>
</taxonomicName>
), 
<bibRefCitation id="EFE28AA2D82BFFE6FA831995FF58B88E" author="Milne, W." pageId="10" pageNumber="26" pagination="47 - 84" refId="ref7491" refString="Milne, W. (1916) On the bdelloid rotifera of South Africa. Part 1. Journal of the Quekett Microscopical Club, 13, 47 - 84. https: // doi. org / 10.5962 / bhl. part. 9295" type="journal article" year="1916">Milne (1916)</bibRefCitation>
referred to this appendage as a spur without an explanation and this attribution has since been accepted by all subsequent authors who discussed this species. However, in the absence of any supporting evidence (for example, embryological), the implied homology of the caudal appendage of the 
<taxonomicName id="4C738CD0D82BFFE6FC6D19F9FB32BB45" box="[951,1160,511,537]" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="undetermined">
<emphasis id="B9072B41D82BFFE6FC6D19F9FB95BB44" box="[951,1071,511,536]" italics="true" pageId="10" pageNumber="26">Henoceros</emphasis>
species
</taxonomicName>
with the paired spurs of the other bdelloid species is not clear. In any case, the caudal appendage of 
<taxonomicName id="4C738CD0D82BFFE6FC2B1A25FB23BB61" authorityName="Örstan" authorityYear="2021" box="[1009,1177,547,573]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FC2B1A25FB23BB61" box="[1009,1177,547,573]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
appears different from the similar-looking organ of 
<taxonomicName id="4C738CD0D82BFFE6FE0C1A41FDF4BB3C" authorityName="Milne" authorityYear="1916" box="[470,590,583,608]" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="genus">
<emphasis id="B9072B41D82BFFE6FE0C1A41FDF4BB3C" box="[470,590,583,608]" italics="true" pageId="10" pageNumber="26">Henoceros</emphasis>
</taxonomicName>
in that the former has two attachment nibs (
<figureCitation id="1348EBD6D82BFFE6FBE31A41FB71BB3D" box="[1081,1227,583,609]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="10" pageNumber="26">Figs. 10C, D</figureCitation>
), while that of 
<taxonomicName id="4C738CD0D82BFFE6FAA81A41FEF4BBD9" baseAuthorityName="Milne" baseAuthorityYear="1916" class="Eurotatoria" family="Philodinavidae" genus="Henoceros" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="falcatus">
<emphasis id="B9072B41D82BFFE6FAA81A41FEF4BBD9" italics="true" pageId="10" pageNumber="26">Henoceros falcatus</emphasis>
</taxonomicName>
has a pointed tip and presumably one attachment nib, although this has not been explicitly stated in the literature (
<bibRefCitation id="EFE28AA2D82BFFE6FEE91A89FE02BBF5" author="Milne, W." box="[307,440,655,681]" pageId="10" pageNumber="26" pagination="47 - 84" refId="ref7491" refString="Milne, W. (1916) On the bdelloid rotifera of South Africa. Part 1. Journal of the Quekett Microscopical Club, 13, 47 - 84. https: // doi. org / 10.5962 / bhl. part. 9295" type="journal article" year="1916">Milne 1916</bibRefCitation>
; 
<bibRefCitation id="EFE28AA2D82BFFE6FE191A89FD03BBF5" author="Ricci, C. &amp; Melone, G." box="[451,697,655,681]" pageId="10" pageNumber="26" pagination="77 - 85" refId="ref7721" refString="Ricci, C. &amp; Melone, G. (1998) The Philodinavidae (Rotifera Bdelloidea): a special family Hydrobiologia, 385, 77 - 85. https: // doi. org / 10.1023 / A: 1003458611180" type="journal article" year="1998">Ricci &amp; Melone 1998</bibRefCitation>
). Until the embryological development of 
<taxonomicName id="4C738CD0D82BFFE6FB4A1A89FA8CBBF5" authorityName="Örstan" authorityYear="2021" box="[1168,1334,655,681]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FB4A1A89FA8CBBF5" box="[1168,1334,655,681]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
has been studied, I would prefer to refer to the subject organ simply as a caudal appendage.
</paragraph>
<paragraph id="8BCCF753D82BFFE6FF1D1AD1FF66BD69" blockId="10.[151,1437,151,2013]" pageId="10" pageNumber="26">
An additional difference between 
<taxonomicName id="4C738CD0D82BFFE6FD9D1AD1FD55BBAD" authorityName="Örstan" authorityYear="2021" box="[583,751,727,753]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FD9D1AD1FD55BBAD" box="[583,751,727,753]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
and the philodinavid species is that the new species has two toes, while all of the philodinavids have four. A possible objection against this argument is that in the current taxonomy of bdelloids, the toe numbers are primarily used to separate the genera, but not the families (
<bibRefCitation id="EFE28AA2D82BFFE6FADB1B19FA36BA65" author="Bartos, E." box="[1281,1420,798,825]" pageId="10" pageNumber="26" pagination="241 - 500" refId="ref6908" refString="Bartos, E. (1951) The Chechoslovak rotatoria of the order Bdelloidea. Vestnik Ceskoslovenske zoologicke spolecnosti, 15, 241 - 500." type="journal article" year="1951">Bartoš 1951</bibRefCitation>
). Strictly speaking, this is applicable only to the 
<taxonomicName id="4C738CD0D82BFFE6FD7C1B45FC8DBA01" authorityName="C.G.Ehrenberg" authorityYear="1838" box="[678,823,835,861]" class="Eurotatoria" family="Philodinidae" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="family">Philodinidae</taxonomicName>
, which includes genera with toe numbers of two, three and four and one genus with an adhesive plate; whereas in the families 
<taxonomicName id="4C738CD0D82BFFE6FC7D1B61FB9FBADD" box="[935,1061,871,897]" class="Eurotatoria" family="Adinetidae" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="family">Adinetidae</taxonomicName>
, 
<taxonomicName id="4C738CD0D82BFFE6FBF51B61FB67BADD" box="[1071,1245,871,897]" class="Eurotatoria" family="Habrotrochidae" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="family">Habrotrochidae</taxonomicName>
and 
<taxonomicName id="4C738CD0D82BFFE6FAC81B61FF7BBAF9" authorityName="Harring. This" authorityYear="1913" class="Eurotatoria" family="Philodinavidae" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="family">Philodinavidae</taxonomicName>
, the toe numbers of all genera are uniform as three, three and four, respectively. When the other morphological differences between some of the philodinid genera are also taken into account, the inter-generic differences in the toe numbers suggest that the 
<taxonomicName id="4C738CD0D82BFFE6FE021BD5FDDCBAB1" authorityName="C.G.Ehrenberg" authorityYear="1838" box="[472,614,979,1005]" class="Eurotatoria" family="Philodinidae" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="family">Philodinidae</taxonomicName>
is not monophyletic. In short, the toe numbers may indeed be appropriate, along with other traits, to separate bdelloid families. Further discussion of this matter is outside the scope of this paper.
</paragraph>
<paragraph id="8BCCF753D82BFFE6FF1D1C39FB28BD21" blockId="10.[151,1437,151,2013]" pageId="10" pageNumber="26">
Taken together, these considerations render the 
<taxonomicName id="4C738CD0D82BFFE6FD061C39FC3EBD05" authorityName="Harring. This" authorityYear="1913" box="[732,900,1087,1113]" class="Eurotatoria" family="Philodinavidae" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="family">Philodinavidae</taxonomicName>
unsuitable for the placement of 
<taxonomicName id="4C738CD0D82BFFE6FB351C39FA2FBD05" authorityName="Örstan" authorityYear="2021" box="[1263,1429,1087,1113]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FB351C39FA2FBD05" box="[1263,1429,1087,1113]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
. Therefore, the new family 
<taxonomicName id="4C738CD0D82BFFE6FE191C65FDCCBD21" authorityName="Örstan" authorityYear="2021" box="[451,630,1123,1149]" family="Coronistomidae" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="10" pageNumber="26" phylum="Rotifera" rank="family">Coronistomidae</taxonomicName>
is erected here to accommodate 
<taxonomicName id="4C738CD0D82BFFE6FC3E1C65FB31BD21" authorityName="Örstan" authorityYear="2021" box="[996,1163,1123,1149]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FC3E1C65FB31BD21" box="[996,1163,1123,1149]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
.
</paragraph>
<paragraph id="8BCCF753D82BFFE6FF1D1C81FD45BCC1" blockId="10.[151,1437,151,2013]" pageId="10" pageNumber="26">
<bibRefCitation id="EFE28AA2D82BFFE6FF1D1C81FE23BDFD" author="Beauchamp, P. M. de" box="[199,409,1159,1185]" pageId="10" pageNumber="26" pagination="1 - 410" refId="ref6934" refString="Beauchamp, P. M. de (1909) Recherches sur les rotiferes: les formations tegumentaires et l'appareil digestif. Archives de Zoologie Experimentale et Generale, Serie 4, 10, 1 - 410." type="journal article" year="1909">Beauchamp (1909</bibRefCitation>
: Fig. XI) saw in the foot of 
<taxonomicName id="4C738CD0D82BFFE6FD0D1C81FBBDBDFE" authority="(Kellicott)" baseAuthorityName="Kellicott" baseAuthorityYear="1888" box="[727,1031,1159,1186]" class="Eurotatoria" family="Philodinidae" genus="Rotaria" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="socialis">
<emphasis id="B9072B41D82BFFE6FD0D1C81FC31BDFD" box="[727,907,1159,1185]" italics="true" pageId="10" pageNumber="26">Rotaria socialis</emphasis>
(Kellicott)
</taxonomicName>
only one pair of five mononucleate glands positioned longitudinally, but could not follow their ducts as they were intertwined around each other. He did note that there was a granular substance filling the glands. 
<bibRefCitation id="EFE28AA2D82BFFE6FCBA1CC9FB96BDB5" author="Brakenhoff, H." box="[864,1068,1231,1257]" pageId="10" pageNumber="26" pagination="125 - 182" refId="ref6972" refString="Brakenhoff, H. (1937) Zur Morphologie der Bdelloidea. Zoologische Jahrbucher, 63, 125 - 182." type="journal article" year="1937">Brakenhoff (1937</bibRefCitation>
: Abb. 11) gave a more complete description of the two pairs of gland complexes in the foot of 
<taxonomicName id="4C738CD0D82BFFE6FC981CF5FB3FBC52" authority="(Giglioli)" baseAuthorityName="Giglioli" baseAuthorityYear="1863" box="[834,1157,1267,1294]" class="Eurotatoria" family="Philodinidae" genus="Embata" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="parasitica">
<emphasis id="B9072B41D82BFFE6FC981CF5FBA8BC50" box="[834,1042,1267,1293]" italics="true" pageId="10" pageNumber="26">Embata parasitica</emphasis>
(Giglioli)
</taxonomicName>
: the dorsal pair consisted of five longitudinally arranged mononucleate glands along each side of the foot, while each set of the ventral pair, positioned more medially, consisted of one trinucleate elongated gland and one posterior mononucleate gland. He was apparently able to resolve the individual ducts exiting the gland complexes and showed them to twist around each other as they extended into the spurs and the toes.
</paragraph>
<paragraph id="8BCCF753D82BFFE6FF1D1DA1FDD1BFE1" blockId="10.[151,1437,151,2013]" pageId="10" pageNumber="26">
The overall anatomy of the gland complexes in the foot of 
<taxonomicName id="4C738CD0D82BFFE6FCB31DA1FBABBC9D" authorityName="Örstan" authorityYear="2021" box="[873,1041,1447,1473]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FCB31DA1FBABBC9D" box="[873,1041,1447,1473]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
(
<figureCitation id="1348EBD6D82BFFE6FBFB1DA1FB32BC9D" box="[1057,1160,1447,1473]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="10" pageNumber="26">Fig. 10A</figureCitation>
) is similar to that of the gland complexes in the foot of 
<taxonomicName id="4C738CD0D82BFFE6FE231DCDFD31BCB8" baseAuthorityName="Giglioli" baseAuthorityYear="1863" box="[505,651,1483,1508]" class="Eurotatoria" family="Philodinidae" genus="Embata" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="parasitica">
<emphasis id="B9072B41D82BFFE6FE231DCDFD31BCB8" box="[505,651,1483,1508]" italics="true" pageId="10" pageNumber="26">E. parasitica</emphasis>
</taxonomicName>
(
<bibRefCitation id="EFE28AA2D82BFFE6FD401DCDFCE5BCB9" author="Brakenhoff, H." box="[666,863,1483,1509]" pageId="10" pageNumber="26" pagination="125 - 182" refId="ref6972" refString="Brakenhoff, H. (1937) Zur Morphologie der Bdelloidea. Zoologische Jahrbucher, 63, 125 - 182." type="journal article" year="1937">Brakenhoff 1937</bibRefCitation>
: Abb. 11). The photographs of 
<taxonomicName id="4C738CD0D82BFFE6FB1A1DCDFADDBCB9" authorityName="Örstan" authorityYear="2021" box="[1216,1383,1483,1509]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FB1A1DCDFADDBCB9" box="[1216,1383,1483,1509]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
also show the presence of ducts filled with a granular substance (
<figureCitation id="1348EBD6D82BFFE6FC9A1DE9FC68BF55" box="[832,978,1519,1545]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="10" pageNumber="26">Figs. 10C, D</figureCitation>
) similar to what 
<bibRefCitation id="EFE28AA2D82BFFE6FB491DE9FAD3BF55" author="Beauchamp, P. M. de" box="[1171,1385,1519,1545]" pageId="10" pageNumber="26" pagination="1 - 410" refId="ref6934" refString="Beauchamp, P. M. de (1909) Recherches sur les rotiferes: les formations tegumentaires et l'appareil digestif. Archives de Zoologie Experimentale et Generale, Serie 4, 10, 1 - 410." type="journal article" year="1909">Beauchamp (1909)</bibRefCitation>
saw in the foot of 
<taxonomicName id="4C738CD0D82BFFE6FEED1E15FE14BF71" baseAuthorityName="Kellicott" baseAuthorityYear="1888" box="[311,430,1555,1581]" class="Eurotatoria" family="Philodinidae" genus="Rotaria" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="socialis">
<emphasis id="B9072B41D82BFFE6FEED1E15FE14BF71" box="[311,430,1555,1581]" italics="true" pageId="10" pageNumber="26">R. socialis</emphasis>
</taxonomicName>
. One pair of these ducts appear to exit from the posterior ends of the dorsolateral gland complexes and cross over each other before entering the caudal appendage (
<figureCitation id="1348EBD6D82BFFE6FC3E1E31FBF6BF0D" box="[996,1100,1591,1617]" captionStart="FIGURE 10" captionStartId="7.[151,250,1813,1837]" captionTargetBox="[151,1435,741,1789]" captionTargetId="figure-329@7.[151,1435,741,1789]" captionTargetPageId="7" captionText="FIGURE 10: Coronistomus impossibilis gen. nov., sp. nov., details of foot anatomy.A, preserved compressed specimen, foot. B, live specimen, toes. C, live specimen, caudal appendage with two pairs of ducts (a, a’, b, b’) and a pair of muscles (c, c’). D, live specimen, foot. an: attachment nib; ca: caudal appendage; dlc: dorsolateral gland complex; vmc: ventromedial gland complex." figureDoi="http://doi.org/10.5281/zenodo.4736232" httpUri="https://zenodo.org/record/4736232/files/figure.png" pageId="10" pageNumber="26">Fig. 10D</figureCitation>
). Ducts are also present inside the toes. But because the numerous twisting ducts and the retractor muscles create a tangle too crowded to resolve easily in photographs, I have so far not been able to fully trace any of the other ducts inside the caudal appendage or the toes to any of the gland complexes.
</paragraph>
<paragraph id="8BCCF753D82BFFE7FF1D1EC0FABBB841" blockId="10.[151,1437,151,2013]" lastBlockId="11.[151,1437,151,1185]" lastPageId="11" lastPageNumber="27" pageId="10" pageNumber="26">
<emphasis id="B9072B41D82BFFE6FF1D1EC0FD1DBFBC" bold="true" box="[199,679,1734,1761]" pageId="10" pageNumber="26">Significance of the morphological traits</emphasis>
. An adhesive system incorporating the secretions of two different glands, one for attachment and the other for detachment, the so-called duo-gland system, has been hypothesized to operate in turbellarians, gastrotrichs, nematodes and echinoderms (
<bibRefCitation id="EFE28AA2D82BFFE6FC7B1F09FB6DBE75" author="Lengerer, B. &amp; Ladurner, P." box="[929,1239,1807,1833]" pageId="10" pageNumber="26" pagination="182717" refId="ref7354" refString="Lengerer, B. &amp; Ladurner, P. (2018) Properties of temporary adhesion systems of marine and freshwater organisms. Journal of Experimental Biology, 221, jeb 182717." type="journal article" year="2018">Lengerer &amp; Ladurner 2018</bibRefCitation>
). The presence of two pairs of anatomically different gland complexes and two pairs of ducts for two attachment nibs (two ducts per nib) in the caudal appendage of 
<taxonomicName id="4C738CD0D82BFFE6FDDC1F51FD17BE2D" authorityName="Örstan" authorityYear="2021" box="[518,685,1879,1905]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="10" pageNumber="26" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82BFFE6FDDC1F51FD17BE2D" box="[518,685,1879,1905]" italics="true" pageId="10" pageNumber="26">C. impossibilis</emphasis>
</taxonomicName>
suggests that a duo-gland adhesive system may also be present in this species. On the other hand, the retractor muscles present in the foot of bdelloids, which are responsible for the retraction of the foot during their characteristic leech-like crawling (
<bibRefCitation id="EFE28AA2D82BFFE6FC7A1F99FB62BEE5" author="Hochberg, R. &amp; Litvaitis, M. K." box="[928,1240,1951,1977]" pageId="10" pageNumber="26" pagination="57 - 64" refId="ref7111" refString="Hochberg, R. &amp; Litvaitis, M. K. (2000) Functional morphology of the muscles in Philodina sp. (Rotifera: Bdelloidea). Hydrobiologia, 432, 57 - 64. https: // doi. org / 10.1023 / A: 1004003509017" type="journal article" year="2000">Hochberg &amp; Litvaitis 2000</bibRefCitation>
), point to a more straightforward mechanism of detachment (the “mechanical model” in 
<bibRefCitation id="EFE28AA2D82BFFE6FC671FC5FB40BE81" author="Lengerer, B. &amp; Ladurner, P." box="[957,1274,1987,2013]" pageId="10" pageNumber="26" pagination="182717" refId="ref7354" refString="Lengerer, B. &amp; Ladurner, P. (2018) Properties of temporary adhesion systems of marine and freshwater organisms. Journal of Experimental Biology, 221, jeb 182717." type="journal article" year="2018">Lengerer &amp; Ladurner, 2018</bibRefCitation>
): when the retractor muscles of the foot, which reach into the caudal appendage of 
<taxonomicName id="4C738CD0D82AFFE7FC4F1891FB80B9ED" authorityName="Örstan" authorityYear="2021" box="[917,1082,151,177]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="11" pageNumber="27" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82AFFE7FC4F1891FB80B9ED" box="[917,1082,151,177]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
, contract, the caudal appendage and the toes may simply be pulled off the surface without the need for a special glandular secretion to break their attachment to the substrate. But if this model is correct, it remains to be explained why there are two pairs of anatomically different gland complexes in the foot of 
<taxonomicName id="4C738CD0D82AFFE7FD111905FCC8B841" authorityName="Örstan" authorityYear="2021" box="[715,882,259,285]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="11" pageNumber="27" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82AFFE7FD111905FCC8B841" box="[715,882,259,285]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
and probably in all other bdelloids.
</paragraph>
<paragraph id="8BCCF753D82AFFE7FF1D1921FB4BBBD9" blockId="11.[151,1437,151,1185]" pageId="11" pageNumber="27">
When water flows over an immersed surface a boundary layer forms on the surface. Within the boundary layer the flow velocity is zero at the surface and increases gradually to the velocity of the bulk water at a certain distance (thickness) from the surface (
<bibRefCitation id="EFE28AA2D82AFFE7FE3A1969FCB2B8D5" author="Lampert, W. &amp; Sommer, U." box="[480,776,367,393]" pageId="11" pageNumber="27" refId="ref7269" refString="Lampert, W. &amp; Sommer, U. (2007) Limnoecology. Oxford University Press, Oxford, 324 pp." type="book" year="2007">Lampert &amp; Sommer 2007</bibRefCitation>
). Many organisms live entirely within boundary layers and do not experience the flow of the bulk water. Even though at the bulk water flow velocity of the Hawlings River (
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/s) the boundary layer may only be a few millimeters thick (
<bibRefCitation id="EFE28AA2D82AFFE7FC5519B1FB1BB88D" author="Silvester, N. R. &amp; Sleigh, M. A." box="[911,1185,438,465]" pageId="11" pageNumber="27" pagination="433 - 448" refId="ref7763" refString="Silvester, N. R. &amp; Sleigh, M. A. (1985) The forces on microorganisms at surfaces in flowing water. Freshwater Biology, 15, 433 - 448. https: // doi. org / 10.1111 / j. 1365 - 2427.1985. tb 00213. x" type="journal article" year="1985">Silvester &amp; Sleigh 1985</bibRefCitation>
), 
<taxonomicName id="4C738CD0D82AFFE7FB6C19B1FAE6B88D" authorityName="Örstan" authorityYear="2021" box="[1206,1372,439,465]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="11" pageNumber="27" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82AFFE7FB6C19B1FAE6B88D" box="[1206,1372,439,465]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
, having a diameter of ~ 
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(
<figureCitation id="1348EBD6D82AFFE7FE1E19DDFDA4B8A9" box="[452,542,474,501]" captionStart="FIGURE 5" captionStartId="4.[151,250,1657,1681]" captionTargetBox="[164,1423,560,1633]" captionTargetId="figure-223@4.[164,1423,560,1633]" captionTargetPageId="4" captionText="FIGURE 5: Coronistomus impossibilis gen. nov., sp. nov., eyespots and other details of live specimens.A, holotype, lateral. B, paratype, dorsal. es: eyespot; lf: longitudinal fold; lp: lappet; pp: papillae." figureDoi="http://doi.org/10.5281/zenodo.4736222" httpUri="https://zenodo.org/record/4736222/files/figure.png" pageId="11" pageNumber="27">Fig. 5A</figureCitation>
), can remain completely within the boundary layer on the surfaces of immersed rocks. However, theoretical calculations also suggest that when water is flowing at 
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/s perpendicular (as opposed to parallel) to an individual of 
<taxonomicName id="4C738CD0D82AFFE7FDF51A25FD6FBB61" authorityName="Örstan" authorityYear="2021" box="[559,725,547,573]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="11" pageNumber="27" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82AFFE7FDF51A25FD6FBB61" box="[559,725,547,573]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
(which would have a Reynolds number of ~30 for its diameter), vortexes and turbulence may develop around the rotifer (
<bibRefCitation id="EFE28AA2D82AFFE7FCC61A41FB8BBB3D" author="Silvester, N. R. &amp; Sleigh, M. A." box="[796,1073,582,609]" pageId="11" pageNumber="27" pagination="433 - 448" refId="ref7763" refString="Silvester, N. R. &amp; Sleigh, M. A. (1985) The forces on microorganisms at surfaces in flowing water. Freshwater Biology, 15, 433 - 448. https: // doi. org / 10.1111 / j. 1365 - 2427.1985. tb 00213. x" type="journal article" year="1985">Silvester &amp; Sleigh 1985</bibRefCitation>
). This may not be an unrealistic scenario considering that 
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<emphasis id="B9072B41D82AFFE7FE6C1A6DFDE7BBD9" box="[438,605,619,645]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
was found in samples from rock surfaces facing upstream.
</paragraph>
<paragraph id="8BCCF753D82AFFE7FF1D1A89FE30BDFD" blockId="11.[151,1437,151,1185]" pageId="11" pageNumber="27">
The Hawlings River’s flow velocity of 
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/s is above 
<bibRefCitation id="EFE28AA2D82AFFE7FC9C1A89FBBABBF5" author="Nielsen, A." box="[838,1024,654,681]" pageId="11" pageNumber="27" pagination="176 - 196" refId="ref7536" refString="Nielsen, A. (1950) The torrential invertebrate fauna. Oikos, 2, 176 - 196. https: // doi. org / 10.2307 / 3564791" type="journal article" year="1950">Nielsen’s (1950)</bibRefCitation>
lower limit (
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/s) of “swift-flowing” water. Therefore, 
<taxonomicName id="4C738CD0D82AFFE7FE481AB5FD8DBB91" authorityName="Örstan" authorityYear="2021" box="[402,567,691,717]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="11" pageNumber="27" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82AFFE7FE481AB5FD8DBB91" box="[402,567,691,717]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
may be considered a “torrential” species. Some morphological and behavioral traits of 
<taxonomicName id="4C738CD0D82AFFE7FF2E1AD1FE21BBAD" authorityName="Örstan" authorityYear="2021" box="[244,411,727,753]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="11" pageNumber="27" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82AFFE7FF2E1AD1FE21BBAD" box="[244,411,727,753]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
may now be interpreted as adaptations to increase the chances of these rotifers to remain in their microhabitat when they are subjected to fast and turbulent water flow. The long and the thick toes as well as the caudal appendage are expected to provide a strong attachment while serving as a pivot to allow the animal to explore its surroundings securely. The bdelloid rotifers with the typical corona on pedicels are either swimmers or stationary feeders (
<bibRefCitation id="EFE28AA2D82AFFE7FEB41B6EFDBABADD" author="Orstan, A." box="[366,512,871,899]" pageId="11" pageNumber="27" pagination="611 - 620" refId="ref7693" refString="Orstan, A. (2020) Taxonomical characterization of bdelloid rotifers in the family Philodinidae. Quekett Journal of Microscopy, 43, 611 - 620." type="journal article" year="2020">Örstan 2020</bibRefCitation>
). Even though the stationary feeders may not move much, the beating of the cilia on their open coronas creates a forward thrust that makes their bodies rise above the substrate to which their feet are attached. In comparison, the corona morphology of 
<taxonomicName id="4C738CD0D82AFFE7FCD61BA9FC09BA95" authorityName="Örstan" authorityYear="2021" box="[780,947,943,969]" class="Eurotatoria" family="Philodinavidae" genus="Coronistomus" kingdom="Animalia" order="Bdelloidea" pageId="11" pageNumber="27" phylum="Rotifera" rank="species" species="impossibilis">
<emphasis id="B9072B41D82AFFE7FCD61BA9FC09BA95" box="[780,947,943,969]" italics="true" pageId="11" pageNumber="27">C. impossibilis</emphasis>
</taxonomicName>
, being an adaptation for grazing within the sediment, does not make the rotifer’s body rise above the substrate and thereby reduces its chances of getting carried away by the water flow. Finally, the stickiness of the egg, as indicated by the debris attached to it (
<figureCitation id="1348EBD6D82AFFE7FB321BF1FAFABD4D" box="[1256,1344,1015,1041]" captionStart="FIGURE 9" captionStartId="6.[151,250,1890,1914]" captionTargetBox="[151,1435,870,1866]" captionTargetId="figure-160@6.[151,1435,870,1866]" captionTargetPageId="6" captionText="FIGURE 9: Coronistomus impossibilis gen. nov., sp. nov. A, preserved specimen (stained with neutral red), dorsal aspect. B, egg of the holotype with attached debris (stack of four photographs; brightfield). C, live specimen, lateral aspect of posterior body. All to the same scale. as: anal swelling; ca: caudal appendage; dtg: dorsotransverse gland; vm: vitellarium." figureDoi="http://doi.org/10.5281/zenodo.4736230" httpUri="https://zenodo.org/record/4736230/files/figure.png" pageId="11" pageNumber="27">Fig. 9B</figureCitation>
), makes it more likely that the egg will stay where it is deposited. These proposed correlations of morphology with water flow rate should be confirmed by further study and also in other bdelloid species that live exclusively in similar habitats; otherwise, their presentation as general rules may lead to contradictory and inconsistent results (
<bibRefCitation id="EFE28AA2D82AFFE7FA9F1C65FF68BDFD" author="Nielsen, A." pageId="11" pageNumber="27" pagination="176 - 196" refId="ref7536" refString="Nielsen, A. (1950) The torrential invertebrate fauna. Oikos, 2, 176 - 196. https: // doi. org / 10.2307 / 3564791" type="journal article" year="1950">Nielsen 1950</bibRefCitation>
; 
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).
</paragraph>
</subSubSection>
</treatment>
</document>