Uroptychus nebulosus,

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: 337-340

publication ID

http://doi.org/10.5281/zenodo.3760976

DOI

http://doi.org/10.5281/zenodo.3805135

persistent identifier

http://treatment.plazi.org/id/2A1C87B5-FEC6-4C3E-FF3D-DF9FFE5A7DB0

treatment provided by

Felipe

scientific name

Uroptychus nebulosus
status

n. sp.

Uroptychus nebulosus  n. sp.

Figures 160View FIGURE 160, 161View FIGURE 161, 305IView FIGURE 305

Uroptychus sibogae  — Poore et al. 2011: 330, pl. 8, fig. A (not U. sibogae Van Dam, 1933  ).

TYPE MATERIAL — Holotype: Tonga. BORDAU 2 Stn CH 1621, 24°19’S, 176°23’W, 570-573 m, 18.VI.2000, ♂ 9.5 mm ( MNHN-IU-2014-16804)GoogleMaps  . Paratypes: Tonga. BORDAU 2, station data as for the holotype, 1 ♂ 8.7 mm, 1 ov. ♀ 9.0 mm (MNHN-IU-2014-16805)GoogleMaps  . – Stn CP1620, 24°18’S, 176°20’W, 572 m, 18.VI.2000, 1 ♂ 9.6 mm, 1 ov. ♀ 11.1 mm ( MNHN- IU-2014-16806).GoogleMaps  Solomon Islands. SALOMON 1 Stn DW1788, 09°19’S, 160°15’E, 341-343 m, 30.IX.2001, 2 ♂ 4.8, 5.1 mm (MNHN-IU-2014-16807).GoogleMaps  SALOMON 2 Stn CP2262, 7°56.4’S, 156°51.2’E, 460-487 m, 3.XI.2004, 1 ♂ 4.9 mm (MNHN-IU-2014-16808)GoogleMaps  . – Stn CP2263, 7°54.8’S, 156°51.3’E, 485-520 m, 3.XI.2004, 1 ♂ 7.2 mm, 1 ov. ♀ 6.8 mm (MNHN-IU-2014-16809).GoogleMaps  Vanuatu. SANTO Stn AT09, 15°42’S, 167°01’E, 481 m, 17.IX.2006, 2 ♂ 6.6, 7.6 mm ( MNHN- IU-2014-16810)GoogleMaps  . – Stn AT10, 15°41.1’S, 167°00.5’E, 509-559 m, 17.IX.2006, 1 ♂ 6.5 mm (MNHN-IU-2014-16811)  . – Stn AT73, 15°40.8’S, 167°00.5’E, 514-636 m, 07.X.2006, 1 ♂ 8.1 mm (MNHN-IU-2014-16812), 3 ♂ 5.6-7.9 mm, 1 ov. ♀ 6.0 mm, 1 ♀ 5.7 mm (MNHN-IU-2014-16813).GoogleMaps  New Caledonia, Hunter and Matthew Islands. VOLSMAR Stn DW05, 22°26’S, 171°46’E, 620-700 m, 01.VI.1989, 4 ♂ 4.4-6.2 mm, 1 ov. ♀ 5.7 mm (MNHN-IU-2014-16814).GoogleMaps  New Caledonia. MUSORSTOM 4 Stn CP216, 22°59.5’S, 167°22.0’E, 490-515 m, with Chrysogorgiidae  gen. sp. ( Calcaxonia  ), 29.IX.1985, 1 ♂ 5.7 mm (MNHN-IU-2014-16815).GoogleMaps  French Polynesia, Austral Islands . BENTHAUS Stn DW2001, 22°26.6’S, 151°20.1’W, 200-550 m, 23.XI.2002, 1 ov. ♀ 6.1 mm (MNHN-IU-2014-16816)GoogleMaps  .

ETYMOLOGY„ From the Latin nebulosus  (indefinite, obscure), alluding to the systematic status of this species which is very similar to U. sibogae Van Dam, 1933  and U. longicarpus  n. sp., but the species is distinctive in subtle detail.

DISTRIBUTION„ Solomon Islands, Vanuatu, Hunter-Matthew Islands, New Caledonia, Tonga and French Polynesia; 200- 700 m.

SIZE„ Males, 4.4-9.6 mm; females, 5.7-11.1 mm; ovigerous females from 5.7 mm.

DESCRIPTION„ Medium-sized to large species. Carapace: As long as or slightly longer than broad; greatest breadth 1.5 × distance between anterolateral spines. Dorsal surface smooth, with very fine, short setae discernible under high magnification, slightly convex from anterior to posterior, feebly concave between gastric and cardiac regions. Lateral margins slightly convex and slightly divergent posteriorly; anterolateral spine small, located posterior to level of smaller lateral orbital spine, and never overreaching its tip; another spine located at anterior end of branchial region, followed by row of feebly denticulate short ridges; ridged along posterior sixth of length. Rostrum elongate, sharp triangular, with interior angle 27-35°; dorsal surface moderately concave; length 0.4-0.5 × that of remaining carapace, breadth slightly more than half carapace breadth at posterior carapace margin. Pterygostomian flap anteriorly angular, produced to very small spine, surface smooth.

Sternum: Excavated sternum with sharp anterior spine between bases of Mxp1, surface with spine in center. Sternal plastron as long as broad or slightly shorter; lateral extremities divergent posteriorly. Sternite 3 strongly depressed, anterior margin strongly excavated, with 2 well-developed submedian spines nearly contiguous or separated by narrow notch, anterolateral angle rounded or angular. Sternite 4 long relative to breadth, anterolaterally sharp angular; anterolateral margin smoothly straight, length 2.6-3.2 × that of posterolateral margin. Anterolateral margin of sternite 5 anteriorly rounded, 1.5-1.6 × longer than posterolateral margin of sternite 4.

Abdomen: Smooth, with very fine setae. Somite 1 antero-posteriorly convex, not ridged. Somite 2 tergite 2.2-2.4 × broader than long; pleuron with anterolaterally rounded, posterolaterally angular, lateral margin concavely strongly divergent. Pleuron of somite 3 with angular lateral terminus. Telson 0.6-0.7 × as long as broad; posterior plate 1.5-2.1 × longer than anterior plate, emarginate on posterior margin.

Eye: 1.6-2.0 × longer than broad, overreaching midlength of rostrum but not reaching rostral tip; lateral and mesial margins subparallel. Cornea slightly inflated, more than half as long as remaining eyestalk.

Antennule and antenna: Ultimate article of antennule 2.0-2.5 × longer than high. Antennal peduncle not reaching distal end of cornea. Article 2 with very small or obsolescent lateral spine. Antennal scale slightly falling short of or nearly reaching distal end of article 5, 1.6 × broader than article 5. Article 4 unarmed. Article 5 with small distomesial spine, length 2.5-2.6 × that of article 4, breadth 0.4 height of ultimate antennular article. Flagellum of 22-24 segments slightly falling short of distal end of P 1 merus.

Mxp: Mxp1 with bases close to each other. Mxp3 basis with 3 or 4 denticles on mesial ridge, distalmost consistent, others often obsolescent. Ischium with 20-25 denticles on crista dentata, flexor margin distally not rounded. Merus about twice as long as ischium, unarmed, moderately ridged along flexor margin. Carpus unarmed.

P 1: 4.7-5.0 × longer than carapace, massive, setose on fingers and distal part of palm, ventrally granulose except for palm and fingers; triangular dorsal spine on ischium, unarmed elsewhere. Merus 1.1-1.2 × longer than carapace. Carpus 1.1-1.3 × longer than merus. Palm 2.1-2.6 × (males), 2.5-2.7 × (females) longer than broad, 0.9-1.0 × longer than carpus. Fingers gaping in males, not gaping in females and small males, distally incurved, crossing when closed; movable finger 0.6-0.7 × length of palm, opposable margin with medially incised proximal process.

P 2-4: Broad relative to length, dactyli narrow. Meri moderately compressed mesio-laterally, sparingly with long setae, successively shorter posteriorly ( P 3 merus 0.9 × length of P 2 merus, P 4 merus 0.8-0.9 × length of P 3 merus); successively narrower posteriorly ( P 4 merus 0.9 × breadth of P 2 merus, 0.8-0.9 × breadth of P 3 merus); length-breadth ratio, 3.5-3.7 on P 2, 3.3-3.9 on P 3, 3.6-4.0 on P 4; P 2 merus 0.8 × length of carapace, 1.2-1.4 × length of P 2 propodus; P 3 merus subequal to length of P 3 propodus; P 4 merus 0.9 × length of P 4 propodus. Carpi successively shorter posteriorly ( P 3 carpus 0.9 × length of P 2 carpus, P 4 carpus 0.9 × length of P 3 carpus); carpus-dactylus length ratio, 1.3-1.7 on P 2, 1.2-1.4 on P 3, 1.0-1.3 on P 4; carpus-propodus length ratio, 0.6 on P 2, 0.5 on P 3, 0.4-0.5 on P 4. Propodi subequal in length on P 3 and P 4 (shortest on P 2) or on P 2 and P 3 (longest on P 4); flexor margin straight, terminating in pair of spines preceded by 9-11 spines on P 2, 8-9 spines on P 3, 6-8 spines on P 4. Dactyli subequal, 0.6-0.8 × length of carpi on P 2, 0.7-0. 8 × on P 3, 0.8-1.0 × on P 4, 0.4 × length of propodi on P 2-4; flexor margin strongly curving at proximal quarter, with 9-10 subtriangular, somewhat inclined, proximally decreasing spines on P 2, 10-11 spines on P 3, 10-12 spines on P 4, ultimate largest, penultimate and antepenultimate subequal.

Eggs. Number of eggs carried, about 60; size, 1.28 mm × 1.36 mm - 1.37 mm × 1.40 mm.

Color. Pale orange overall, posterior half of carapace translucent white (male 8.1 mm, MNHN-IU-2014-16812; male 6.5 mm, MNHN-IU-2014-16811). The color illustration given under U. sibogae  by Poore et al. (2011) is from one of the photos (MNHN-IU-2014-16811) available to me.

REMARKS — The species is very closely related to U. sibogae Van Dam, 1933  (see below) and U. longicarpus  n. sp. in nearly all aspects. Uroptychus nebulosus  is distinguished from U. sibogae  by subtle morphological differences: the P 2 merus is longer and broader than instead of subequal to or slightly narrower than P 3 merus; the P 2-4 meri are broader relative to length (the length-breadth ratio being 3.7-3.9, 3.4-4.1, 3.6-3.8 versus 5.0-5.6, 5.0-5.3, 4.2-4.6 on P 2, P 3, P 4 respectively; the P 2 merus is much shorter than instead of subequal to the carapace (0.8 versus 1.0); and the cornea is not so well inflated as in U. sibogae  . Uroptychus longicarpus  n. sp. is unique in the genus in having the P 4 carpus distinctly longer than the P 3 carpus.

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Chirostylidae

Genus

Uroptychus

Loc

Uroptychus nebulosus

Baba, Keiji 2018
2018
Loc

Uroptychus sibogae

POORE G. C. B. & ANDREAKIS N. 2011: 330
2011