Uroptychus parisus, Baba, 2018

Baba, Keiji, 2018, Chirostylidae of the Western and Central Pacific: Uroptychus and a new genus (Crustacea: Decapoda: Anomura), Tropical Deep-Sea Benthos (Mémoires du Muséum national d'Histoire naturelle 212), pp. 1-612 : 381-385

Uroptychus parisus n. sp.

Figures 189 , 190

Uroptychus scandens — McCallum & Poore 2013:165, fig. 12F.

TYPE MATERIAL — Holotype: New Caledonia. HALIPRO 1 Stn CP 877, 23°03’S, 166°59’E, 464-480 m, 31.III.1994, ov. ♀ 3.3 mm ( MNHN-IU-2013-8563 ) . Paratypes: New Caledonia. HALIPRO 1 Stn CP877, 23°03’S, 166°59’E, 464-480 m, 31.III.1994, collected together with holotype, 1 ov. ♀ 3.4 mm (MNHN-IU-2014-16839). BATHUS 2 Stn CP738, 23°02’S, 166°56’E, 558-647 m, 13.V.1993, 1 ov. ♀ 3.3 mm (MNHN-IU-2014-16840). MUSORSTOM 4 Stn CP169, 18°55’S, 163°12’E, 600 m, 17.IX.1985, 1 ov. ♀ 3.6 mm (MNHN-IU-2014-16841) . – Stn CP170, 18°57’S, 163°13’E, 485 m, 17.IX.1985, on Pennatula sp. ( Pennatulacea , Pennatulidae ), 1 ♂ 2.9 mm, 2 ov. ♀ 3.2, 3.3 mm (MNHN-IU-2014-16842) ; 1 ♂ 2.7 mm, 1 ov. ♀ 3.6 mm, 1 ♀ 3.7 mm (MNHN-IU-2013-8562) . – Stn CP195, 18°54’S, 163°23’E, 470 m, 19.IX.1985, 1 ov. ♀ 3.1 mm (MNHN-IU-2014-16843) . – Stn CP236, 22°11.3’S, 167°15.0’E, 495-550 m, 2.X.1985, 1 ♂ 3.5 mm, 6 ov. ♀ 3.1-3.5 mm, 3 ♀ 2.8-3.3 mm (MNHN-IU-2014-16844) . – Stn CP 238, 22°13.0’S, 167°14.0’E, 500-510 m, 2.X.1985, 1 ov. ♀ 3.2 mm (MNHN-IU-2013-8570). New Caledonia, Chesterfield Islands . MUSORSTOM 5 Stn CP 389, 20°44.95’S, 160°53.67’E, 500 m, 22.X.1986, 1 ov. ♀ 4.1 mm (MNHN-IU-2014-16845). New Caledonia, Loyalty Ridge. MUSORSTOM 6 CP467, 21°06’S, 167°32’E, 530-575 m, 21.II.1989, 1 ov. ♀ 3.6 mm (MNHN-IU-2014-16850). New Caledonia, Norfolk Ridge. NORFOLK 2 Stn CP 2121, 23°23’S, 168°00’E, 486-514 m, 1.XI.2003, 1 ♂ 4.2 mm (MNHN-IU-2014-12794). Solomon Islands. SALOMON 1 Stn CP 1786, 09°21’S, 160°25’E, 387 m, 30.IX.2001, 1 ♂ 3.1 mm, 4 ov. ♀ 3.4-4.1 mm, 2 ♀ 3.1, 3.4 mm (MNHN-IU-2013-8568, MNHN-IU-2013-12276) . – Stn CP1804, 9°32.0’S, 160°37.4’E, 309-328 m, 2.X.2001, 1 ♀ 4.2 mm (MNHN-IU-2014-16851) . – Stn CP1851, 10°27.6’S, 162°00.6’E, 297-350 m, 6.X.2001, 2 ♂ 2.4, 3.5 mm, 4 ov. ♀ 3.2- 3.5 mm, 4 ♀ 3.7-4.1 mm (MNHN-IU-2013-8564) . SALOMON 2 Stn CP2227, 6°37.2’S, 156°12.7’E, 508-522 m, 28.X.2004, 1 ♂ 3.4 mm, 1 ov. ♀ 3.0 mm (MNHN-IU-2014-16852) . – Stn CP2287, 8°40.8’S, 157°24.6’E, 253-255 m, 6.XI.2004, 1 ov. ♀ 3.9 mm, 1 ♀ 3.3 mm (MNHN-IU-2014-16853). Vanuatu. MUSORSTOM 8 Stn CP984, 19°19.62’S, 169°26.43’E, 480- 544 m, 23.IX.1994, 1 ♂ 3.8 mm (MNHN-IU-2014-16846) . – Stn CP1026, 17°50.35’S, 168°39.33’E, 437-504 m, 28.IX.1994, 1 ♂ 3.3 mm, 1 ov. ♀ 3.9 mm (MNHN-IU-2014-16847). – Stn CP1136, 15°40.62’S, 167°01.60’E, 398-400 m, 11.X.1994, 2 ov. ♀ 4.5, 4.5 mm (MNHN-IU-2013-12277 & MNHN-IU-2013-12278). – Stn CP1049, 16°39’S, 168°03’E, 469-525 m, 1.X.1994, 2 ov. ♀ 4.0, 4.5 mm, 1 ♀ 4.7 mm (MNHN-IU-2014-16848). SANTO Stn AT120, 15°40.4’S, 167°01.0’E, 431- 445 m, 19.X.2006, 1 ♂ 4.2 mm, 1 ov. ♀ 3.8 mm (MNHN-IU-2014-16849). Philippines. MUSORSTOM 1 Stn CP42, 13°54’N, 120°29’E, 379-407 m, 24.III.1976, 1 ♀ 4.3 mm (MNHN-IU-2013-12279) .

ETYMOLOGY„ From the Greek parisos (evenly balanced), alluding to the eyestalk being evenly broad from proximal to distal, not broadened proximally as in the related species Uroptychus scandens Benedict, 1902 .

DISTRIBUTION„ Chesterfield Islands, Solomon Islands, Vanuatu, Loyalty Ridge, New Caledonia, Norfolk Ridge, Philippines; 253- 647 m.

SIZE„ Males, 2.4-4.2 mm; females, 2.8-4.7 mm; ovigerous females from 3.0 mm.

DESCRIPTION„ Small species. Carapace: Broader than long (0.8 × as long as broad); greatest breadth 1.5-1.8 × distance between anterolateral spines. Dorsal surface setose laterally, with very small spines on epigastric, hepatic, anterior branchial regions, and often on anterior part of posterior branchial region, those on hepatic region somewhat larger. Lateral margins often slightly constricted between hepatic and branchial regions, convex along branchial region, with row of small spines; anterolateral spine larger than others, directed somewhat anterolaterally, overreaching much smaller lateral orbital spine. Rostrum narrow triangular, directed straight forward on dorsal surface, directed anterodorsally on ventral surface, with interior angle of 23-25°; lateral margins somewhat concave, more strongly convergent near tip, with several obsolescent denticles; dorsal surface somewhat concave; length slightly smaller than (0.8-0.9 x) breadth, 0.4 × that of remaining carapace, breadth slightly less than half carapace breadth at posterior carapace margin. Lateral orbital spine situated slightly anterior to level of anterolateral spine. Pterygostomian flap anteriorly somewhat roundish, produced to strong sharp spine; surface with small spines on anterior half, including row of spines along dorsal margin anterior to linea anomurica.

Sternum: Excavated sternum with slightly convex anterior margin; surface smooth, without ridge and central spine, with setae along anterior margin. Sternal plastron 0.8-0.9 × as long as broad, lateral extremities between sternites 4 and 7 convex, sternite 6 broadest; anterior margin of sternite 3 broadly and deeply excavated nearly in semicircular shape, with pair of small median spines, often with single spine instead or with no spine. Sternite 4 having anterolateral margin feebly convex, anteriorly produced to distinct spine followed by a few smaller spines proximally, length 1.4 × as long as posterolateral margin. Anterolateral margin of sternite 5 as long as posterior margin of sternite 4. Abdomen. Pleura similar in both sexes. Somite 1 gently convex from anterior to posterior. Somite 2 tergite 2.5-2.9 × broader than long, pleural lateral margin feebly or barely concavely divergent posteriorly, ending in rounded margin. Pleura of somites 3-5 laterally rounded. Telson 0.4-0.5 × as long as broad; posterior plate slightly or moderately emarginate, 1.5- 2.0 × longer than anterior plate.

Eyes: Elongate, 2.0-2.2 × longer than broad, very slightly overreaching apex of rostrum, equally broad proximally and distally; lateral margin convex, mesial margin concave. Cornea 0.5 × length of remaining eyestalk and slightly inflated, breadth slightly larger than greatest breadth of remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle 2.6-3.3 × longer than high. Antennal peduncle reaching or slightly overreaching apex of rostrum. Antennal scale fused with article 2, 1.7-1.8 × broader than article 5, ending in point half to four-fifths length of article 5, laterally with 1-3 sharp spines including spine at ordinary site of article 2, proximalmost usually strong, rarely small. Articles 4 with distomesial spine (with accompanying smaller spine ventrolateral to it in holotype). Article 5 with small distomesial spine, length 1.5 × that of article 4, breadth 0.4-0.5 × height of ultimate article of antennule. Flagellum of 8-10 segments ending in midlength of P1 merus, apical seta somewhat longer than flagellum.

Mxp: Mxp1 with bases broadly separated. Mxp3 with long setae. Basis with 3 or 4 proximally diminishing denticles on mesial ridge. Ischium with small but distinct spine lateral to distal end of flexor margin, crista dentata with several obsolescent denticles on proximal half. Merus more than twice (2.5 x) length of ischium, ridged along flexor margin; with 4 spines on distal third of flexor margin and 1 or 2 distolateral spines. Carpus unarmed.

P1: Slender, subcylindrical, 6.0-7.1 × (males), 5.8-6.6 (females) × longer than carapace. Ischium dorsally with basally broad, depressed, bifurcate short spine, ventromesially unarmed. Merus 1.3-1.6 × longer than carapace, dorsally bearing 2 rows of single, bifurcate or trifurcate spines (1 row along mesial margin and another row directly mesiodorsal to it). Carpus 1.3-1.4 × longer than merus, unarmed. Palm 4.3-4.9 × (males), 3.9-6.7 × (females) longer than broad, 0.9-1.0 × as long as carpus, very slightly broadened distally. Fingers relatively narrow distally, somewhat gaping in proximal third; opposable margins fitting to each other in distal two-thirds with row of very small spines or denticles; movable finger 0.4-0.5 × length of palm, with obtuse process at midpoint of gaping portion.

P2-4: Thickly setose like P1. Meri successively shorter posteriorly (P3 merus 0.8-0.9 × length of P2 merus, P4 merus 0.8-0.9 × length of P3 merus), slightly broader on P3 and P4 than on P2; length-breadth ratio, 4.1-4.7 on P2, 3.1-3.7 on P3, 2.7-3.1 on P4; dorsal margins with 5-7 small spines on proximal half on P2 and P3, unarmed on P4; P2 merus as long as carapace, rarely slightly shorter; 1.3-1.4 × longer than P2 propodus; P3 merus 1.2-1.3 × length of P3 propodus; P4 merus 1.1-1.2 × length of P4 propodus. Carpi successively shorter posteriorly; carpus-propodus length ratio, 0.5 on P2-4. Propodi successively shorter posteriorly; flexor margin straight in lateral view, with pair of small distal spines only. Dactyli successively shorter posteriorly, shorter than carpus; dactylus-carpus length ratio, 0.6-0.7 on P2, 0.7-0.8 on P3 and P4; dactylus-propodus length ratio, 0.3 on P2, 0.3-0.4 on P3, 0.4 on P4; truncate, bearing 7 or 8 slender spines obscured by setae, 3-4 of these located on terminal margin, remainder on flexor margin, distalmost (terminal and directly adjacent to extensor margin) slightly smaller than distal second.

Eggs. Number of eggs carried, 7-14; size, 0.71 × 0.79 mm - 0.92 × 0.71 mm.

REMARKS — The new species is grouped together with U. articulatus n. sp., U. imparilis n. sp. and U. scandens Benedict, 1902 by having truncate dactyli of P2-4. Their relationships are discussed under U. scandens (see below).

Molecular data provided by L. Corbari (personal comm.) suggest that the female from the Philippines (MNHN-IU-2013-12279), the two females from Vanuatu (MNHN-IU-2013-12277 and 12278) and one of seven specimens from the Solomon Islands (MNHN-IU-2013-12276) are different from one another at a specific level. However, I am at a loss to discover any morphological differences, for which extensive studies are required.

The material reported under U. scandens from western Australia by McCallum & Poore (2013) may be referable to this species (A. McCallum, person. comm.).

Figures

FIGURE 189 Uroptychus parisus n. sp., holotype, ovigerous female 3.3 mm (MNHN-IU-2013-8563).A, carapace and anterior part of abdomen,dorsal. B, same,setae omitted,lateral.C, sternal plastron,with excavated sternum and basal parts of Mxp1.D, right pleura of abdominal somites 2-5, dorsolateral. E, telson.F, left antenna, ventral.G, right Mxp3, ventral.H, same,setae omitted, lateral.Scale bars: 1 mm.

FIGURE 190 Uroptychus parisus n.sp.,holotype,ovigerous female 3.3 mm (MNHN-IU-2013-8563).A,left P1,dorsal.B, same,proximal part,setae omitted, ventral.C, right P2,lateral.D, same,distal part, setae omitted. E, right P3, setae omitted, lateral.F, same,distal part,lateral.G, right P4,setae omitted,lateral.H, same, distal part, lateral. Scale bars: 1 mm.