Elasmopus sivaprakasami Myers, Trivedi & Vachhrajani, 2018

Myers, Alan A., Trivedi, Jigneshkumar N., Gosavi, Swapnil & Vachhrajani, Kauresh D., 2018, Elasmopus sivaprakasami sp. nov., a new species of amphipod (Senticaudata, Maeridae) from Gujarat State, India, Zootaxa 4402 (1), pp. 182-188 : 183-187

publication ID	https://doi.org/ 10.11646/zootaxa.4402.1.10
publication LSID	lsid:zoobank.org:pub:4CC9E480-91F3-4DD2-B748-7784E494481B
DOI	https://doi.org/10.5281/zenodo.5960688
persistent identifier	https://treatment.plazi.org/id/7D3387E7-FFA7-FF9C-12B9-8B07371BFEE1
treatment provided by	Plazi
scientific name	Elasmopus sivaprakasami Myers, Trivedi & Vachhrajani
status	sp. nov.

Treatment

Elasmopus sivaprakasami Myers, Trivedi & Vachhrajani View in CoL sp. nov.

( FigS 1–4 View FIGURE 1 View FIGURE 2 View FIGURE3 View FIGURE4 )

Elasmopus japonicus View in CoL . ― SiVaprakasam, 1970, 278, figs 3–5, not E. japonicus Stephensen, 1932 View in CoL , 490, figs 1, 2.

Type Material. Holotype male, 12.1 mm, ( ZSI, WRC-C.1693), Shivrajpur village (22°19'58'N 68°57'01''E), underneath rock Surface, 22 March 2017, Coll. Dhruva Trivedi and Swapnil GoSavi . Allotype female, 9.3 mm, (ZSI, WRC-C.1694) Same data aS holotype. ParatypeS 3 maleS, 7.3 mm; 9.4 mm: 14.6 mm; 3 femaleS, 9.2 mm; 7.3 mm; 6.9 mm,(ZSI, WRC-C1695), Same data aS holotype.

Other material. 15 maleS, 7.2 mm – 14.8 mm; 10 femaleS 6.4 mm – 9.6 mm, (ZL-AR-AM-2), Shivrajpur village (22° 19' 58' N; 68° 57' 01'' E), underneath rock Surface, 20 April 2017, Coll. JigneSh Trivedi and KaureSh Vachhrajani.

Type locality. Shivrajpur village (22°19'58''N 68°57'01''E), coral reef, intertidal, SauraShtra coaSt, Gujarat State, India GoogleMaps

Etymology. The SpecieS iS named in honor of Dr. Tiruvettipuram Ekambaram SivaprakaSam of Southern Regional Centre, Zoological Survey of India, Chennai, Tamilnadu for hiS workS on Indian Amphipoda and for firSt deScribing thiS SpecieS when attributing it to a related SpecieS.

Description. BaSed on male holotype, 12 mm.

Head. Head cephalic lobe rounded, with notch; eye Subreniform. Antenna 1 leSS than half body length; peduncular article 1 and 2 Subequal in length; article 3 half length of article 2; flagellum a little Shorter than the peduncle with 24 articleS; acceSSory flagellum with three long articleS and a rudimentary fourth article. Antenna 2 about half length of antenna 1; peduncular articleS 4 and 5 Subequal in length; flagellum longer than peduncular article 5 with 12 articleS. Labrum rounded, diStally SetoSe. Labium mandibular projectionS acute. Mandible molar Strong; lacinia mobiliS with 5 SpineS; palp 3-articulate; articleS 1 and 2 Short; article 3 falcate, twice length of article 2. Maxilla 1 inner plate elongate and Slender with two long terminal Setae; palp 2-articulate. Maxilla 2 lacking oblique Setal row. Maxilliped palp Stout; article 2 extending beyond end of outer plate.

Pereon. Gnathopod 1 coxa rounded, produced anteriorly; baSiS Stout; carpuS one and a half time aS long aS propoduS, heavily SetoSe on inner face; propoduS palm oblique; dactyluS fitting palm. Gnathopod 2 much larger than gnathopod 1; coxa longer than broad; baSiS relatively Slender; carpuS Short, cup-Shaped; propoduS very enlarged, Subovoid, palm Small, rounded with 8 Stout, recurved, robuSt Setae, inner diStal face with a further 3 recurved, robuSt Setae; dactyluS long, greatly overlapping palm, diStinctly falcate. Pereopods 3–4 Slender; dactyluS Short, Scarcely one third length of propoduS. Pereopod 5 baSiS Sub ovoid, poSterior margin Serrate. Pereopod 6 baSiS Sub rectangular, poSterior margin Serrate. Pereopod 7 baSiS elongate, poSterior margin evenly convex, Serrate.

Pleon. Urosome segment 1 with a Smooth triangular dorSal proceSS on itS poSterior half. Epimera 1–3 poSterodiStal corner with Small Spine, poSterior margin with a few fine Setae. Uropod 1 biramouS; peduncle a little longer than rami with long, Stout, diStal, robuSt Setae; rami Subequal in length with many robuSt Setae. Uropod 2 Similar to uropod 1, but peduncle Shorter than rami. Uropod 3 rami much longer than peduncle; outer ramuS Stouter and a little longer than inner ramuS. Telson deeply cleft, each lobe terminally deeply notched and with 3 Strong robuSt Setae.

Female (Sexually dimorphic characterS). BaSed on female, 9.3 mm. Gnathopod 1 Similar to that of male, but coxa leSS Strongly produced anteriorly, carpuS and propoduS Subequal in length. Gnathopod 2 Similar to that of male, but much Smaller; carpuS a little longer; propoduS Subovoid; dactyluS Slender, fitting palm.

Habitat. Underneath rockS on coral platform.

Distribution. Currently known only from India. Gujarat State (preSent material) and Tamil Nadu ( SivaprakaSam 1970).

Remarks. Five SpecieS of Elasmopus CoSta, 1853 are characterized by the preSence of a dorSal hump on uroSome Segment 1. Four previouSly deScribed SpecieS are E. menurte Barnard, 1974 and E. woodjonesi HugheS & Lowry, 2011 from AuStralia, E. neglectus Chilton, 1915 from New Zealand and E. japonicus StephenSen, 1932 from Japan. The fifth SpecieS, deScribed here, E. sivaprakasami sp. nov. differS from both E. woodjonesi and E. neglectus in the Shape of the hump on the dorSum of uroSome Segment 1 which iS acute in theSe two SpecieS, but triangular-blunt in E. sivaprakasami sp. nov. (aS it iS alSo in E. japonicus and E. menurte ). It alSo differS from E. neglectus in the Shape of epimeron 3, which haS a Small Spine in E. sivaprakasami sp. nov. but iS Strongly acute in E. neglectus . In addition, pereopod 7 iS Serrate in E. sivaprakasami sp. nov., but pectinate in E. neglectus . Elasmopus sivaprakasami sp. nov. alSo differS alSo from E. woodjonesi in the long and SetoSe male gnathopod 2 propoduS (Short, broad and weakly SetiferouS in E. woodjonesi ).

Elasmopus menurte iS very Similar to E. sivaprakasami sp. nov., but differS from it in having the male gnathopod 2 dactyluS evenly curved (falcate in E. sivaprakasami sp. nov.), the inner ramuS of uropod 3 only 70% aS long aS the outer ramuS (only a little Shorter in E. sivaprakasami ) and the telSon with a broad apical excavation on each lobe (narrow excavation in E. sivaprakasami ). Elasmopus sivaprakasami sp. nov. iS alSo very cloSe to E.

japonicus , from Japan, but differS primarily from that SpecieS in the Structure of the male gnathopod 2. In E. japonicus there iS a forward projecting lappet without teeth on the lateral Side of the dactyl hinge that iS entirely abSent in E. sivaprakasami sp. nov. In addition, the dactyluS in E. japonicus iS evenly convex, whereaS in E. sivaprakasami sp. nov., it iS markedly falcate. The material deScribed from the Gulf of Mannar by SivaprakaSam (1970) under the name E. japonicus appearS to be conSpecific with preSent material.