A new species of scleractinian associated shrimp of the genus Palaemonella (Crustacea, Decapoda, Palaemonidae) with a redescription of Palaemonella orientalis Dana, 1852 Author Fransen, Charles H. J. M. Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands Author Veer, Eva Van Der 0000-0003-4561-1545 Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands & eva. vanderveer @ naturalis. nl; https: // orcid. org / 0000 - 0003 - 4561 - 1545 eva.vanderveer@naturalis.nl Author Frolová, Pavlína 0000-0002-9108-0805 Department of Biology and Ecology, University of Ostrava, Chittussiho 10, CZ- 71000 Ostrava, Czech Republic. pavlina. frolova @ osu. cz; https: // orcid. org / 0000 - 0002 - 9108 - 0805 pavlina.frolova@osu.cz text Zootaxa 2022 2022-12-05 5214 4 557 580 journal article 202077 10.11646/zootaxa.5214.4.5 8abb041d-95e0-4002-8f65-869fc596cf71 1175-5326 7397768 EA09F278-F742-4E04-9F6D-44CB2A42C517 Palaemonella rubrolineata sp. nov. ( Figs. 1–8 ) Palaemonella spec. : Frolová et al ., in prep.. Material examined. MZB Cru 5448 : 1 ovigerous female holotype , pocl. 2.2mm ; stn RAJ.41, Indonesia , Raja Ampat Islands , West Papua , SE Gam , Desa Besir , 00°27.802′S , 130°41.243′E , 2.xii.2007 , depth 5 m , on Pocillopora damicornis , collected by C.H.J.M. Fransen , CF142. Paratypes . RMNH .CRUS.D. 53070 : 2 ovigerous females, pocl. 2.1–2.2mm ; 1 male , pocl. 1.5mm ; same locality as holotype , GenBank accession nrs. OP306073 (COI); OP304831 (16S) . RMNH .CRUS.D. 48816 : 2 ovigerous females, pocl. 1.6 and 1.8mm ; 2 non-ovigerous females with abdominal bopyroid, pocl. 1.5mm ; 4 males , one with bopyroids on abdomen and antennula, pocl. 0.8–1.6mm ; stn MAL.15, Indonesia , Moluccas , Ambon , Ambon bay , S coast, cape W of Amahusu, 03°44′S 128°08′E , 16.xi.1996 , depth ca. 15 m , scuba diving, on Seriatopora hystrix , collected by C.H.J.M. Fransen. RMNH .CRUS.D. 53067 : 1 male pocl. 2.2mm , 1 juvenile pocl. 1.6mm ; stn RAJ.02, Indonesia , Raja Ampat Islands , West Papua , E Kri Island , Sorido resort lagoon , near jetty, 00°33.347′S 130°41.225′E , 19.xi.2007 , depth unknown, on Seriatopora hystrix ; collected by E. van der Veer , GenBank accession no. OP326597 (16S), photo C.H.J.M. Fransen . RMNH.CRUS .D. 53068 : 1 ovigerous female (rostrum broken, P2–5 missing), pocl. 1.8mm ; stn RAJ.49, Indonesia , Raja Ampat Islands , West Papua , NW off Mansuar I., Lalosi reef , 00°32.892′S 130°29.852′E , 6.xii.2007 , depth unknown, on Seriatopora hystrix , collected by E. van der Veer , GenBank accession no. OP326598 (16S), photo C.H.J.M. Fransen. MNHN-IU- 2014- 22476 : 1 ovigerous female, pocl. 1.9mm ; stn FR18, Vanuatu , Santo , NW Tutuba Island , 15°19′47.892″S 167°10′1.128″E , 18.ix.2006 , depth unknown, steep reef slope, collected by C.H.J.M. Fransen , GenBank accession no. OP326599 (16S) . Description . Small slender shrimp of slightly compressed body form. Carapace ( Fig. 1A ) smooth, slightly swollen posteriorly; orbit obsolescent; inferior orbital angle slightly produced; antennal spine long, slender, acute and marginal, reaching distal margin of basicerite; hepatic spine distinct, slightly shorter than antennal spine, located distinctly lower than antennal spine; anterolateral angle rounded, not produced. Rostrum ( Fig. 1A–C ) well developed, straight, horizontal, reaching distal margin of scaphocerite, with 6 or 7 acute dorsal teeth, of which 0–2 small and subdistal, slightly separated from proximal teeth, proximalmost tooth postorbital, second tooth at level of orbit; ventral margin with single row of short setae, with single acute tooth at level of distal margin of intermediate segment of antennular peduncle. Abdomen ( Fig. 8A, B ) normal, third tergite not produced, sixth segment ( Fig. 1D ) about 1.9 times length of fifth, 1.3 times longer than deep, with posterolateral and posteroventral angles bluntly produced; pleura of first four segments enlarged, broadly rounded, fifth segment ( Fig. 1D ) with posterolateral tooth. Telson ( Fig. 1E ) about 1.4 times longer than sixth abdominal segment, 2.0 times longer than proximal width, lateral margins convergent, sublinear, with two pairs of small subequal dorsal spines at about 0.51 and 0.74 of telson length, distal margin ( Fig. 1F ) about 0.32 of proximal margin width, rounded, without median process, lateral spines small, similar to dorsal spines, intermediate spines robust, 4.6 times as long as lateral spines, submedian spines about half length of intermediate spines, setulose. Eye ( Fig. 1A ) with whitish globular cornea with red lines, with distinct accessory pigment spot dorsally; cornea almost as wide as maximum width of eyestalk; eyestalk 1.2 times longer than maximum width. Antennula ( Fig. 2A ) normal; basal segment of antennular peduncle about half as long as scaphocerite, with acute ventromedial tooth, distal margin convex, with plumose setae, distolateral tooth reaching halfway intermediate segment, lateral margin slightly convex, medial margin straight with row of plumose setae, statocyst normal; stylocerite slender, acute, reaching to half segment length; intermediate and distal segments subequal in length, together about 0.5 of basal segment length; flagella long, slender, upper flagellum biramous, proximal 8–16 segments fused (usually 9–10), shorter free ramus with 3 segments, with 5–10 groups of aesthetascs, longer free ramus slender. Antenna ( Fig. 2B ) normal; basicerite armed with short acute distolateral spine; ischiocerite and merocerite normal; carpocerite subcylindrical, reaching to about 0.25 of scaphocerite length; flagellum well developed; scaphocerite extending well beyond antennular peduncle, 4 times longer than maximum width, distal margin rather small, broadly rounded, lateral margin concave with acute distolateral tooth exceeding distal margin of lamina. Epistome and labrum normal. Fourth thoracic sternite ( Fig. 1G ) with strong, broad, blunt, median process. Fifth thoracic sternite ( Fig. 1G ) with shallow lateral plates posteromedial of second pereiopods with acute triangular submedian processes. Sixth to eight thoracic sternites unarmed, increasing in width posteriorly. Mandible ( Fig. 3A ) robust, with small unsegmented palp with few small simple setae; molar process stout with large angular teeth and brushes of stout setae; incisor process also stout with three large acute distal teeth. Maxillula ( Fig. 3B ) with upper lacinia slender, with two rows of robust simple and serrulate spines medially; lower lacinia slender, setose distally; palp distinctly bilobed, upper lobe with single small simple seta, lower lobe with a small, ventral, single, short, recurved seta. Maxilla ( Fig. 3C ) with basal endite well developed, distinctly bilobed; distal and proximal lacinia equal in length, both fringed medially by many long simple setae, median border without setae; coxal endite obsolete, median margin straight, without setae; scaphognathite about twice as long as proximal width; palp well developed, basally broad, tapering distally, indistinctly two-segmented, with few plumose setae on lateral border. First maxilliped ( Fig. 4A ) with basal and coxal endites distinct; basal endite broad, anterolateral border sparsely setose, medial margin straight, with numerous slender simple and serrulate setae; coxal endite medially biconvex, sparsely setose; exopod well developed, flagellum with about 6 plumose setae distally, caridean lobe small, narrow; coxa with very large bilobed exopod, anterior lobe slightly larger than posterior lobe; palp tapering distally with one large plumose seta subdistally on medial border. Second maxilliped ( Fig. 4B ) with endopod normally developed; with dactylar segment narrow, 4 times longer than broad, densely fringed with numerous coarsely serrulate, spiniform, and long curled, finely serrulate setae medially; distomedial lobe of propodal segment slightly produced, rounded, with row of long slender simple and serrulate setae, ventrolateral margin devoid of setae; carpal segment distomedially angular, without setae, unarmed; meral segment medially excavate, without setae; basal and ischial segments fused, both segments medially excavate, with few short setae medially; exopod normal, with long plumose setae distally; coxal segment slightly produced medially, with few long setae; epipod small, simple, subrectangular, without podobranch. FIGURE 1 . Palaemonella rubrolineata sp. nov. , RMNH.CRUS.D.53067. A, B, E–G, male pocl. 2.2mm; C, D, juvenile pocl. 1.6mm. A, carapace and anterior appendages, lateral view; B, C, rostrum, lateral view; D, abdominal segments 4–6, lateral view; E, caudal fan, dorsal view; F, telson tip, dorsal view; G, thoracic sternites 4 and 5, ventral view. Scales: A = 2mm; B–D, G = 1mm; E = 0.5mm; F = 0.25mm. FIGURE 2 . Palaemonella rubrolineata sp. nov. , male pocl. 2.2mm, RMNH.CRUS.D.53067. A, right antennula, dorsal view; B, right antenna, ventral view. Scale = 0.5mm. FIGURE 3 . Palaemonella rubrolineata sp. nov. , male pocl. 2.2mm, RMNH.CRUS.D.53067. A, right mandible, ventral view; B, right maxillula, ventral view; C, right maxilla, ventral view. Scale = 0.25mm. FIGURE 4. Palaemonella rubrolineata sp. nov. , male pocl. 2.2mm, RMNH.CRUS.D.53067. A, right first maxilliped, ventral view; B, right second maxilliped, ventral view; C, right third maxilliped, ventral view. Scale = 0.5mm. Third maxilliped ( Fig. 4C ) with endopod slender, reaching with terminal segment beyond carpocerite; ischiomerus and basis distinct, ischiomerus almost 5 times longer than wide, flattened and twisted, setose medially, otherwise glabrous, with 3 robust spines in distal two thirds; carpal segment 5 times longer than wide, 0.90 of ischiomeral length, subcylindrical, with groups of long serrulate setae medially; terminal segment 0.55 of ischiomeral segment, tapering distally with terminal spine, medial margin with groups of short serrulate setae; basis with few simple setae along slightly convex median margin; exopod well developed, reaching distal margin of ischiomerus, with numerous plumose setae distally; coxa with small medial lobe and rounded epipod laterally. First pereiopods ( Fig. 5A ) slender, exceeding carpocerite with distal part merus, carpus and chela; chela ( Fig. 5B ) normal, slightly compressed, palm twice as long as deep, with several rows of cleaning setae proximoventrally, fingers about as long as palm, slender, tapering, both with brushes of simple setae and hooked tip distally, cutting edges simple, entire; carpus 1.5 times chela length, slender, 6 times longer than distal width, tapering slightly proximally, with several cleaning setae distoventrally; merus about as long as carpus, about 7 times longer than wide; ischium and basis with several long simple setae medially; coxa with small setose ventromedial lobe. Second pereiopods ( Fig. 5C, E ) equal and similar; chela about 2.6 times carapace length, palm smooth about 3.3 times longer than deep, slightly swollen proximally, fingers ( Fig. 5D, F ) 0.6 times palm length, slender, dactylus about 5.4 times longer than proximal depth, dorsal margin slightly convex, tip hooked, acute, cutting edge with 2 teeth in proximal half, distal cutting edge entire; fixed finger similar, with 1 large tooth at level between two dactylar teeth and 3 small teeth proximally; carpus about 0.4 of chela length, about 5 times longer than distal width, tapering proximally, constricted then flared distally with blunt angular dorsal lobe; merus slightly longer than carpus, 6.4 times longer than central width, armed with distomesial tooth; ischium about 0.5 length of merus, tapering proximally; basis and coxa without special features. FIGURE 5. Palaemonella rubrolineata sp. nov. , male pocl. 2.2mm, RMNH.CRUS.D.53067. A, right first pereiopod, ventral view; B, idem, chela, medial view; C, right second pereiopod, ventral view; D, idem distal part of chela, medial view; E, left second pereiopod, ventral view; F, idem, distal part of chela, medial view. Scale A = 2mm; B = 0.25mm; C, E = 4mm; D, F = 1mm. FIGURE 6. Palaemonella rubrolineata sp. nov. , male pocl. 2.2mm, RMNH.CRUS.D.53067. A, right third pereiopod; B, idem dactylus; C, right fourth pereiopod; D, idem dactylus. Scale A, C = 1.25mm; B, D = 0.125mm. FIGURE 7. Palaemonella rubrolineata sp. nov. , male pocl. 2.2mm, RMNH.CRUS.D.53067. A, right fifth pereiopod; B, idem, dactylus; C, right first pleopod; D, right second pleopod. Scale A = 1.25mm; B = 0.125mm; C, D = 0.25mm. Third pereiopods ( Fig. 6A ) slender, exceeding carpocerite by carpus, propodus and dactylus; dactylus ( Fig. 6B ) simple, slightly curved, 0.18 of propodus length, 3.6 times longer than proximal depth, corpus 2.6 times longer than proximal width, distal width 0.36 times proximal width, dorsal margin convex, with 3–4 simple setae at about 0.65 of length, ventral margin proximally slightly convex, distally concave, armed, with minute distal accessory tooth, without setae; unguis indistinctly demarcated, 0.42 of corpus length, simple, curved, distally acute; propodus about 13 times longer than wide, slightly compressed, straight, uniform, with many long slender setae distally, with one distoventral spine and two similar spines in distal third; carpus normal, about almost half propodus length, unarmed; merus as long as propodus, 9.3 times longer than wide, uniform, unarmed; ischium, basis and coxa without special features. Fourth pereiopods ( Fig. 6C, D ) similar to third, slightly longer. Fifth pereiopods ( Fig. 7A, B ) similar to fourth, slightly longer, propodus with one subdistal ventral spine, few rows of serrulate setae distoventrally. Uropods ( Fig. 1E ) extending beyond telson; protopodite robust, unarmed; exopod with lateral margin straight, non-setose, with small acute posterolateral tooth, flanked medially by mobile spine twice as long as posterolaterlal tooth; endopod slightly shorter than exopod. Pleopods with endopods shorter than exopods. Ova about 50, size 0.38mm . FIGURE 8. Palaemonella rubrolineata sp. nov. , colour pattern and host: A, B, male, RMNH.CRUS.D.53067; C, D, RMNH. CRUS.D.53068, photographs, Charles H.J.M. Fransen. First pleopod of female with endopod almost half as long as exopod, with long plumose setae medially and distally. Male endopod of first pleopod ( Fig. 7C ) half as long as exopod, about 3.5 times longer than wide, with median margin concave, distally slightly expanded, with relatively short plumose marginal setae. Endopod of second pleopod ( Fig. 7D ) 0.8 times length of exopod; appendix masculina well developed, with several rows of strong serrulate setae, just falling short of appendix interna. Size . Maximal pocl. in males 1.6mm , in ovigerous females 2.2mm . Coloration ( Fig. 8 ). Body and appendages translucent with reddish tinge. Thorax and abdomen with few yellow spots and small white chromatophores. Eyestalks with red longitudinal lines and few white chromatophores anteriorly. Red spots at base of uropods and at joints of pereiopods. Cutting edges of second pereiopod chela red. Host . Scleractinia : Pocilloporidae : Pocillopora damicornis (Linnaeus, 1758) and Seriatopora hystrix Dana, 1846 . Distribution . The species has been recorded from Ambon and Raja Ampat, Indonesia and Santo, Vanuatu . Etymology . Named after the red stripes on the cutting edges of the chelae and on the eyestalks combining the Latin word ‘ruber’ = red and ‘lineatus’ = stripes. Remarks . The new species is most closely related to P. orientalis (see Frolová et al ., in prep.). A unique feature both species share is the wreath of long setae at the distal part of the ambulatory propodi ( Figs. 6A–D , 7A, B , 14A–D , 15A, B ). The new species differs from P. orientalis in: 1) the presence of a hepatic spine ( Fig. 1A ) which is absent in P. orientalis ( Fig. 9A ); 2) the more slender body and longer appendages ( Fig. 8 ) than in P. orientalis ( Fig. 16A ); 3) the more slender rostrum ( Fig. 1A–C ) than in P. orientalis ( Fig. 9A–C ); 4) the pleura of the fifth abdominal segment having a posterolateral tooth ( Fig. 1D ) while it is broadly rounded in P. orientalis ( Fig. 9D ); 5) having the fingers of the first pereiopods without rows of long serrate setae distally ( Fig. 5B ) whereas these are present in P. orientalis ( Fig. 13A ); 6) having the cutting edges of the second chela as well as the joints of the pereiopods dark red coloured ( Fig. 8A, B ) while these are translucent in P. orientalis ( Fig. 16A ).