<documentID-DOI="http://dx.doi.org/10.3897/zookeys.1016.55071"ID-GBIF-Dataset="16e49379-c3df-4587-85a4-5f8b083cb79c"ID-PMC="PMC7892531"ID-Pensoft-Pub="1313-2970-1016-49"ID-Pensoft-UUID="A0E84531AFDD55CE83CE1920DE511C0B"ID-PubMed="33628078"ID-ZooBank="E25A831ECDAB40609B5F17C22EB3EFC4"ModsDocID="1313-2970-1016-49"checkinTime="1613177956461"checkinUser="pensoft"docAuthor="Gonzalez-Vallejo, Norma Emilia & Amador-Carrillo, Stephanie"docDate="2021"docId="E422A22421B45007BB165FE591C3ED61"docLanguage="en"docName="ZooKeys 1016: 49-61"docOrigin="ZooKeys 1016"docPubDate="2021-02-11"docSource="http://dx.doi.org/10.3897/zookeys.1016.55071"docTitle="Megadenus smithi González-Vallejo & Amador-Carrillo 2021, sp. nov."docType="treatment"docUuid="B1F27E92-096F-4D99-8697-EBA5F1CDD2B2"docUuidSource="ZooBank"docVersion="5"id="A0E84531AFDD55CE83CE1920DE511C0B"lastPageNumber="49"masterDocId="A0E84531AFDD55CE83CE1920DE511C0B"masterDocTitle="Assessment of Megadenus holothuricola Rosen, 1910 (Eulimidae), an endoparasite of Holothuria mexicana Ludwig, 1875 (Holothuriidae) in the southern Gulf of Mexico and the description a new species"masterLastPageNumber="61"masterPageNumber="49"pageNumber="49"updateTime="1732482122434"updateUser="ExternalLinkService">
<mods:titleid="F13959ECD401E73E7E6ADBC2FFF4B35D">Assessment of Megadenus holothuricola Rosen, 1910 (Eulimidae), an endoparasite of Holothuria mexicana Ludwig, 1875 (Holothuriidae) in the southern Gulf of Mexico and the description a new species</mods:title>
<mods:affiliationid="B220AB4275A17C67F9A65E7D5AECC123">El Colegio de la Frontera Sur, Depto. Sistematica y Ecologia Acuatica, Av. Centenario km. 5.5 Chetumal, Quintana Roo, CP. 77014, Mexico</mods:affiliation>
<mods:affiliationid="86D9AD1AD689F76431B66851A39F2041">El Colegio de la Frontera Sur, Depto. Sistematica y Ecologia Acuatica, Av. Centenario km. 5.5 Chetumal, Quintana Roo, CP. 77014, Mexico</mods:affiliation>
<taxonomicNameid="3DC2C3AC8566E6892A064AB2405F20B3"ID-CoL="7S3GX"LSID="http://zoobank.org/B1F27E92-096F-4D99-8697-EBA5F1CDD2B2"authority="González-Vallejo & Amador-Carrillo, 2021"authorityName="González-Vallejo & Amador-Carrillo"authorityYear="2021"class="Gastropoda"family="Eulimidae"genus="Megadenus"higherTaxonomySource="treatment-meta"kingdom="Animalia"lsidName="Megadenus smithi"order="Littorinimorpha"pageId="0"pageNumber="49"phylum="Mollusca"rank="species"species="smithi"status="sp. nov.">Megadenus smithi</taxonomicName>
<figureCitationid="2CD84CC6DC10D4B42B11DFEFE895642C"captionStart="Figure 3"captionStartId="F3"captionText="Figure 3. Megadenus smithi sp. nov. A holotype female in apertural and posterior views (ECOSUR- 0234) SL = 6.5 mm x 4.0 mm wide B paratype male in apertural and lateral view, showing the tentacles SL = 4.0 mm. x 3.5 mm wide C pedal gland view D distal open proboscis view. Scale bars: 1.2 mm (A); 1.0 mm (B); 0.6 mm (C); 0.5 mm (D)."figureDoi="10.3897/zookeys.1016.55071.figure3"httpUri="https://binary.pensoft.net/fig/507833"pageId="0"pageNumber="49">Fig. 3A-D</figureCitation>
<paragraphid="3D77B1A80D08C4BD6086B6219E81B4E3"pageId="0"pageNumber="49">Palmyra Atoll, Central Pacific Ocean, shallow water in reef lagoon.</paragraph>
<paragraphid="99BA18FF4F786D0EBFD6641FA361D0E1"pageId="0"pageNumber="49">This species is being named after the collector Mr. J. Smith, as a means of recognition, for his sampling efforts.</paragraph>
<paragraphid="F9A29EC8164C7DB8734196EA529EA1EA"pageId="0"pageNumber="49">Female shell globose to conical, transparent, fragile, glassy, colorless, fine incremental axial stria; apex mucronate glassy white not tilt; proboscis slightly dark; large pedal gland.</paragraph>
globose, translucent, thin, fragile, colorless, smooth sculpture, with fine axial striae, several growth scars of earlier outer lip positions are irregularly spaced, suture impressed. Adult shell 6.5 mm long; 4.0 mm wide; body whorl 4.5 mm long (holotype Fig.
<figureCitationid="7580E5813CA0F18C6C15912BA556AF4C"captionStart="Figure 3"captionStartId="F3"captionText="Figure 3. Megadenus smithi sp. nov. A holotype female in apertural and posterior views (ECOSUR- 0234) SL = 6.5 mm x 4.0 mm wide B paratype male in apertural and lateral view, showing the tentacles SL = 4.0 mm. x 3.5 mm wide C pedal gland view D distal open proboscis view. Scale bars: 1.2 mm (A); 1.0 mm (B); 0.6 mm (C); 0.5 mm (D)."figureDoi="10.3897/zookeys.1016.55071.figure3"httpUri="https://binary.pensoft.net/fig/507833"pageId="0"pageNumber="49">3A</figureCitation>
). Teleoconch 5.5 convex whorls, three flat, small post-larval whorls, the penultimate whorl 1.0 mm. Aperture broad, inner lip smooth, concave at base, outer lip simple, slightly curved in most protruding part. Protoconch mucronate, two whorls, glassy white, no operculum or periostracum; sexually dimorphic, male with a penis behind the eye, female is 30% larger than male (Fig.
<figureCitationid="4355C2ECC2EFBFAD72CAA9F4FE9D263B"captionStart="Figure 3"captionStartId="F3"captionText="Figure 3. Megadenus smithi sp. nov. A holotype female in apertural and posterior views (ECOSUR- 0234) SL = 6.5 mm x 4.0 mm wide B paratype male in apertural and lateral view, showing the tentacles SL = 4.0 mm. x 3.5 mm wide C pedal gland view D distal open proboscis view. Scale bars: 1.2 mm (A); 1.0 mm (B); 0.6 mm (C); 0.5 mm (D)."figureDoi="10.3897/zookeys.1016.55071.figure3"httpUri="https://binary.pensoft.net/fig/507833"pageId="0"pageNumber="49">3B</figureCitation>
pale cream with reddish pigmentation, seen through transparent shell. Pseudopallium cauldron-shaped in sub-adults arising from the aperture and covering large part of shell, or short mantle folds not covering female shells, smooth. When skin was removed, a thick, rounded pedal gland was visible in the aperture (Fig.
<figureCitationid="B69279AA4A99B45169FCB3DD6368B5A1"captionStart="Figure 3"captionStartId="F3"captionText="Figure 3. Megadenus smithi sp. nov. A holotype female in apertural and posterior views (ECOSUR- 0234) SL = 6.5 mm x 4.0 mm wide B paratype male in apertural and lateral view, showing the tentacles SL = 4.0 mm. x 3.5 mm wide C pedal gland view D distal open proboscis view. Scale bars: 1.2 mm (A); 1.0 mm (B); 0.6 mm (C); 0.5 mm (D)."figureDoi="10.3897/zookeys.1016.55071.figure3"httpUri="https://binary.pensoft.net/fig/507833"pageId="0"pageNumber="49">3C</figureCitation>
<figureCitationid="D7862FB30EC2253898433BBB1F17E105"captionStart="Figure 3"captionStartId="F3"captionText="Figure 3. Megadenus smithi sp. nov. A holotype female in apertural and posterior views (ECOSUR- 0234) SL = 6.5 mm x 4.0 mm wide B paratype male in apertural and lateral view, showing the tentacles SL = 4.0 mm. x 3.5 mm wide C pedal gland view D distal open proboscis view. Scale bars: 1.2 mm (A); 1.0 mm (B); 0.6 mm (C); 0.5 mm (D)."figureDoi="10.3897/zookeys.1016.55071.figure3"httpUri="https://binary.pensoft.net/fig/507833"pageId="0"pageNumber="49">3D</figureCitation>
The new species shares several shell and morphological traits with the other five congeneric species. A comparison of the most important structures, almost all based on the literature, is provided in Table
<tableCitationid="BC553E4CC32FC024A7367EB7B002A063"captionStart="Table 1"captionStartId="T1"captionText="Table 1. Comparison of the main character states separating the species of Megadenus. The information provided is based on literature (Schepman and Nierstrasz 1913; Humphreys and Luetzen 1972; Bouchet and Luetzen 1980; Takano et al. 2017). For M. holothuricola and M. smithi sp. nov. data obtained from specimens."httpUri="http://table.plazi.org/id/10F1725D01C73D5F203F794640F57A9F"pageId="0"pageNumber="49"tableUuid="10F1725D01C73D5F203F794640F57A9F">1</tableCitation>
<taxonomicNameid="AC0A9A933AFF1487B8C8722274BEEAB5"authorityName="González-Vallejo & Amador-Carrillo"authorityYear="2021"class="Gastropoda"family="Eulimidae"genus="Megadenus"kingdom="Animalia"lsidName="Megadenus smithi"order="Littorinimorpha"pageId="0"pageNumber="49"phylum="Mollusca"rank="species"species="smithi">
<taxonomicNameid="E168812DBF46E58DB91D6F444F530134"authorityName="Bouchet & Lutzen"authorityYear="1980"class="Gastropoda"family="Eulimidae"genus="Megadenus"kingdom="Animalia"lsidName="Megadenus oneirophantae"order="Littorinimorpha"pageId="0"pageNumber="49"phylum="Mollusca"rank="species"species="oneirophantae">
<taxonomicNameid="6FE6A49A1BBC6901C524A5F5C707B9A3"authorityName="González-Vallejo & Amador-Carrillo"authorityYear="2021"class="Gastropoda"family="Eulimidae"genus="Megadenus"kingdom="Animalia"lsidName="Megadenus smithi"order="Littorinimorpha"pageId="0"pageNumber="49"phylum="Mollusca"rank="species"species="smithi">
