Munidopsis kexueae, Dong & Gan & Li, 2021

Dong, Dong, Gan, Zhibin & Li, Xinzheng, 2021, Descriptions of eleven new species of squat lobsters (Crustacea: Anomura) from seamounts around the Yap and Mariana Trenches with notes on DNA barcodes and phylogeny, Zoological Journal of the Linnean Society 192 : -

MUNIDOPSIS KEXUEAE SP. NOV.

( FIGS 23, 24; SUPPORTING INFORMATION, FIG. S6D)

Zoobank registration: urn:lsid:zoobank.org:act:5AF6F1C4-7712-4C5F-AF34-C61A311F27F3

Material examined: Holotype, MBM189188 , one male ( PCL 12.3 mm), stn. Y3-5, Y3 seamount near the Yap Trench , West Pacific, 137°49.3’E, 8°57.2’N, 1472 m, coll. bottom trawl of R / V Kexue, 18 December 2014.

Description: Carapace (excluding rostrum) distinctly longer than broad. Frontal margins slightly oblique, antennal spines well developed. Lateral margins parallel, each armed with three distinct spines, including strong anterolateral spine, strong spine at lateral base of anterior cervical groove and small spine at lateral base of posterior cervical groove; posterior branchial margins slightly convergent posteriorly, with oblique ridges extending on to dorsal surface; posterior margin straight, unarmed, with elevated submarginal ridge. Dorsal surface glabrous, covered with transverse interrupted ridges, ridges on gastric, cardic, intestinal and posterior branchial regions much more elevated; cervical grooves distinct, regions well defined. Hepatic region expanding laterally, anterolateral spine with transverse anterior margin. Gastric region distinctly elevated, armed with a pair of prominent epigastric spines. Rostrum narrowly triangular, tip acute, approximately 0.2 times remaining carapace length; dorsal surface smoothly carinate; lateral margins unarmed. Pterygostomial flap with short oblique ridges on lateral surface, anterior end blunt.

Sternal plastron approximately as broad as long. Sternite 3 approximately 3.6 times broader than long, anterior margin slightly crenulate, with shallow median notch. Sternite 4 1.4 times broader than long, with anterior part triangular, contacting median onefifth of sternite 3; ventral surface distinctly depressed. Sternites 5–7 each with transverse ridge interrupted by median groove.

Abdominal tergites with dorsal surfaces glabrous and unarmed; tergites 2 and 3 each with two transverse ridges, posterior ridges low and short; tergite 4 with single low transverse ridge; tergite 6 with straight posterior margin.

Telson composed of 12 plates.

Eyestalk immovable. Peduncle unarmed, visible on dorsal view, broader than cornea, half of cornea length. Cornea hemispheric, globular. Epistomial spine well developed immediately lateral to eyestalk and ventral to frontal margin.

Antennular peduncle with basal article longer than broad, surfaces glabrous; distal margin armed with slender ventrolateral spine; lateral face inflate, armed with distinct dorsal spine.

Antennal peduncle reaching distal one-fifth of rostrum. Article 1 short and immovable, with distinct distolateral spine and small distomesial spine. Article 2 armed with strong distolateral spine. Article 3 with small distomesial spine; Article 4 unarmed.

Third maxilliped slender. Ischium shorter than merus, disto-extensor and distoflexor corners produced as small spines; crista dentata well developed. Merus with extensor margin convex, armed with small distoextensor spine; flexor margin bearing two strong spines; ventral surface with short rugae. Carpus with extensor margin slightly rugose. Propodus broadening distally.

P1 approximately 2.9 times PCL, sparsely covered with stiff setae on surface and margins. Ischium short, armed with distinct dorsal distolateral spine; ventrodistal margin produced. Merus as long as PCL, roughly rectangular in cross-section, forming four longitudinal carinae; dorsal carina armed with a row of eight spines (decreasing in size proximally), including strong dorsodistal spine, dorsomesial carina armed with a row of three spines, including strong distal dorsomesial spine and several elevated rugae, ventromesial carinae armed with a row of four spines, including strong distal ventromesial spine, ventrolateral carina armed with strong distal ventrolateral spine; lateral surface and ventral surface with elevated scale-like rugae. Carpus 0.6 times merus length, distal margin armed with strong dorsal spine, dorsolateral spine, small dorsomesial spine and ventrolateral spine; dorsodistal spine followed by two spines, distal dorsomesial spine followed by row of three spines (subterminal spine largest); surfaces covered with short scale-like rugae. Palm compressed, 0.7 times merus length, 2.3 times longer than broad; surfaces and margins with elevated scale-like rugae; dorsomesial margin with a row of three spines, dorsolateral margin with two spines. Fingers 0.8 times palm length, tips hooked; occlusal margins crenulated, with broad low process on movable finger, and median triangular tooth on fixed finger.

P2–4 slender, bearing sparse simple setae on each segment; P2 approximately 2.4 times PCL, reaching midlength of P1 palm. Meri slender, subequal in breadth and decreasing in length posteriorly, P2 merus 0.9 times PCL, P3 and P4 meri approximately 0.9 times P2 merus length; extensor margin armed with a row of spines; flexor margin rugose, with strong distal spine; lateral surface with short scale-like rugae. Carpi short, subequal in length from P2 to P4, approximately 0.4 times P2 merus length; extensor margin with two longitudinal ridges, mesial ridge armed with one or two strong spines, lateral ridge unarmed; flexor margin with acute distoflexor spine. Propodi slender, subequal in length from P2 to P4, 0.9 times P2 merus length and 12.3 times longer than broad; extensor margin slightly rugose; flexor margin with pair of distal corneous spines. Dactyli approximately 0.4 times propodus length; extensor margin straight on proximal two-thirds, distal claw slightly curving; flexor margin straight, with 13–15 movable corneous spines on distal three-quarter length, each spine based on low triangular tooth, distalmost spine closely appressed to claw.

Pereopods without epipod.

Coloration: Carapace and P1 dark orange; spine tips whitish; P2–4 light orange to whitish.

Habitat: Unknown.

Distribution: Seamount near the Yap Trench, West Pacific; depth 1472–1757 m.

Etymology: The specific name is dedicated to the research vessel Kexue on which the expeditions were carried out.

Remarks: The new species is morphologically similar to M.spinipes MacGilchrist, 1905 from the Indian Ocean in having immovable eyestalks lacking eye spines, a pair of epigastric spines only on the dorsal surface of the carapace, three prominent spines on the lateral margin of the carapace, unarmed rostrum, unarmed abdominal segments and P1 much longer than P2. The new species is different from M. spinipes in having pair of epistomial spines each lateral to the eyestalk and ventral to the frontal margin, and the basal article of antennular peduncle is armed with only two spines. In M. spinipes , such epistomial spine is absent, and the basal article of the antennular peduncle is armed with four spines, including two mesiodistal spines that are absent in the new species ( MacGilchrist, 1905). The absence of the epistomial spine lateral to the eyestalk in M. spinipes was confirmed by the re-examination of the holotype [through photos (Supporting Information, Fig. S8) provided by Dr Kandasamy Valarmathi in ZSI, Kolkata, India, 2019]. However, this spine is common in the M. serricornis ( Ahyong, 2014) species complex, which is a group of species characterized by their trifid rostrum.

Munidopsis kexueae also resemble M. maunga Schnabel & Bruce, 2006 from the New Zealand in having slender P1, pair of epistomial spines, and similar spination on the antennular peduncle and eyestalks. The new species can be readily distinguished from the latter in having longer rostrum exceeding, instead of falling short of, the distal end of antennal peduncle (when directed forward), lateral carapace margin with three instead of two spines, P1 carpus and palm with rows of spines on surfaces instead of unarmed, P2–4 meri with a row of spines nearly on entire extensor margins instead of only on proximal half.

No DNA information for M. spinipes and M. maunga is available for comparative study. The DNA barcodes of the new species were provided in the present study.