Uroptychus quinarius, 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 : 439-443

Uroptychus quinarius n. sp.

Figures 220 , 221

TYPE MATERIAL — Holotype: New Caledonia, Norfolk Ridge. BATHUS 3 Stn CP811, 23°41’S, 168°15’E, 383-408 m, 28.XI.1993, ov. ♀ 2.7 mm ( MNHN-IU-2013-8519 ) . Paratypes: New Caledonia, Norfolk Ridge. BATHUS 3, collected with holotype, 5 ♂ 3.1-3.3 mm, 9 ov. ♀ 2.6-3.5 mm, 1 ♀ 2.2 mm (MNHN-IU-2014-16899) . – Stn CP812, 23°43.38’S, 168°15.98’E, 391-440 m, 28.XI.1993, 3 ♂ 2.9-3.5 mm, 9 ov. ♀ 3.1-3.6 mm, 1 ♀ 3.3 mm (MNHN-IU-2014-16900) . – Stn CP813, 23°45’S, 168°17’E, 410-415 m, 28.XI.1993, 9 ♂ 2.3-3.5 mm, 1 ov. ♀ 4.1 mm, 12 ♀ 3.1-4.0 mm (MNHN- IU-2014-16901) . – Stn CP814, 23°48’S, 168°17’E, 444-530 m, 28.XI.1993, 3 ♂ 2.8, 3.3 mm, 5 ov. ♀ 2.9-3.6 mm (MNHN- IU-2014-16902) . – Stn DW817, 23°42’S, 168°16’E, 405-410 m, 28.XI.1993, 1 ♂ 3.3 mm, 9 ov. ♀ 3.0-3.7 mm, 1 ♀ 3.0 mm (MNHN-IU-2014-16903), 2 ♂ 2.7, 3.3 mm (MNHN-IU-2014-16904) . – Stn DW818, 23°44’S, 168°16’E, 394-401 m, 28.XI.1993, 12 ♂ 2.3-3.8 mm, 24 ov. ♀ 2.4-3.5 mm, 5 ♀ 2.1-3.8 mm (MNHN-IU-2014-16905) . NORFOLK 2 Stn CP2048, 23°43.82’S, 168°16.24’E, 380-389 m, with Primnoidae gen. sp. ( Calcaxonia ), 24.X.2003, 16 ♂ 2.2-3.4 mm, 24 ov. ♀ 2.5- 3.6 mm, 7 ♀ 2.2-3.3 mm (MNHN-IU-2014-16906) . – Stn DW2049, 23°42.88’S, 168°15.43’E, 470-621 m, 24.X.2003, 1 ♂ 3.2 mm, 4 ov. ♀ 3.0-3.4 mm (MNHN-IU-2014-16907) . – Stn CP2050, 23°42.17’S, 168°15.72’E, 377-377 m, 24.X.2003, 4 ♂ 3.1-3.7 mm, 9 ov. ♀ 2.9-3.8 mm, 1 ♀ 3.5 mm (MNHN-IU-2014-16908) . – Stn DW2052, 23°42.29’S, 168°15.27’E, 473- 525 m, 24.X.2003, 1 ♂ 2.9 mm, 2 ov. ♀ 3.2, 3.6 mm, 1 ♀ 3.0 mm (MNHN-IU-2014-16909) . – Stn DW2108, 23°46.52’S, 168°17.12’E, 403-440 m, 31.X.2003, 7 ♂ 2.3-3.3 mm, 18 ov. ♀ 3.4-4.2 mm, 3 ♀ 2.9-3.3 mm (MNHN-IU-2014-16910) . – Stn DW2109, 23°47.46’S, 168°17.04’E, 422-495 m, 31.X.2003, 9 ♂ 2.6-3.8 mm, 19 ov. ♀ 2.7-3.8 mm, 2 ♀ 2.8, 3.5 mm (MNHN-IU-2014-16911) . – Stn DW2110, 23°48.34’S, 168°16.81’E, 493-850 m, 31.X.2003, 2 ov. ♀ 3.4, 3.6 mm (MNHN- IU-2014-16912) . – Stn CP2111, 23°48.56’S, 168°16.78’E, 500-1074 m, 31.X.2003, 2 ov. ♀ 3.7, 3.9 mm, 1 ♀ 3.3 mm (MNHN-IU-2014-16913) . – Stn DW2112, 23°44.44’S, 168°18.40’E, 640-1434 m, 31.X.2003, 1 ov. ♀ 3.8 mm (MNHN- IU-2014-16914) . – Stn DW2142, 23°00.51’S, 168°16.90’E, 550-550 m, 3.XI.2003, 1 ov. ♀ 3.2 mm, 1 ♀ (carapace broken) (MNHN-IU-2014-16915) .

OTHER MATERIAL EXAMINED — New Caledonia, Norfolk Ridge. BERYX 11 Stn CP51, 23°45’S,168°17’E, 390-400 m, 21.X.1992, 1 ov. ♀ 3.1 mm (MNHN-IU-2014-16916), 1 ♀ 3.5 mm (MNHN-IU-2014-16917) . – Stn CP52, 23°47.45’S, 168°17.05’E, 430-530 m, 21.X.1992, 4 ♂ 2.6-3.3 mm, 3 ov. ♀ 2.8-3.6 mm, 1 ♀ 3.2 mm (MNHN-IU-2014-16918) . SMIB 8 Stn DW179, 23°45.87’, 168°16.95’, 400-405 m, 30.I.1993, 1 ♂ 3.3 mm, 1 ♀ 3.0 mm (MNHN-IU-2014-16919) . BATHUS 2 CP736, 23°03’S, 166°58’E, 452-464 m, 13.V.1993, 2 ov. ♀ 3.0, 3.1 mm, 1 ♀ 3.1 mm (MNHN-IU-2014-16920) . SMIB 5 Stn DW98, 23°02’S, 168°16’E, 320-335 m, 14.IX.1989, 1 ov. ♀ 3.2 mm (MNHN-IU-2013-8625) . NORFOLK 1 Stn DW1704, 23°45’S, 168°16’E, 400-420 m, 25.VI.200, 9 ♂ 2.8-3.7 mm, 16 ov. ♀ 2.9-3.9 mm, 1 ♀ 3.0 mm (MNHN-IU-2013-8626) . – Stn CP1706, 23°44’S, 168°17’E, 383-394 m, 25.VI.2001, 4 ♂ 2.7-3.1 mm, 3 ov. ♀ 2.7-4.0 mm (MNHN-IU-2014-16921) . – Stn DW1707, 23°43’S, 168°16’E, 381-493 m, 25.VI.2001, 1 ov. ♀ 3.1 mm (MNHN-IU-2014-16922) . – Stn CP1708, 23°43’S,168°16’E, 381-384 m, 25.VI.2001, 1 ♂ 3.8 mm (MNHN-IU-2014-16923) . LITHIST Stn DW13, 23°45.0’S, 168°16.7’E, 400 m, 12.VIII.1999, 10 ♂ 2.3-3.9 mm, 15 ov. ♀ 2.9-3.9 mm, 4 ♀ 2.4-3.6 mm (MNHN-IU-2014-16924) . – Stn CP15, 23°40.4’S, 168°15.0’E, 389-404 m, 12.VIII.1999, 1 ov. ♀ 3.1 mm (MNHN-IU-2014-16925) . – Stn CP16,23°43.2’S, 168°16.2’E, 379-391 m, 12.VIII.1999, 3 ♂ 2.0-3.6 mm, 3 ov. ♀ 3.1-3.5 mm (MNHN-IU-2014-16926) . Philippines. MUSORSTOM 3 Stn CP133, 11°58’N, 121°52’E, 334-390 m, with Primnoidae gen. sp. ( Calcaxonia ), 5.VI.1985, 1 ♂ 2.3 mm (MNHN-IU-2014-16927) . Indonesia, Kai Islands. KARUBAR Stn CP16, 5°17’S, 132°50’E, 315-349 m, 24.X.1991, 1 ov. ♀ 3.7 mm (MNHN-IU-2014-16928) .

ETYMOLOGY„ From the Latin quinarius (= consisting of five), referring to five spines on the carapace lateral margin, one

of the characters to separate the species from U. dualis n. sp., U. floccus n. sp. and U. lumarius n. sp.

SIZE„ Males, 2.3-3.9 mm; females, 2.1-4.2 mm; ovigerous females from 2.4 mm.

DISTRIBUTION„ Philippines, Kai Islands ( Indonesia), southern New Caledonia and Norfolk Ridge; 377-1074 m.

DESCRIPTION„ Small species. Carapace: Slightly broader than long (0.9 × as long as broad); greatest breadth 1.4 × distance between anterolateral spines. Dorsal surface somewhat convex in profile, with shallow depression bordering gastric and cardiac regions, bearing sparse long setae; epigastric region with transverse row of spines usually small, often obsolescent, lateral-most often larger than others. Lateral margins convex on branchial region, bearing 5 spines; first anterolateral, directed slightly anterolaterally, overreaching much smaller lateral orbital spine, subequal to second and third; third situated about at midlength, second equidistant between first and third; last (fifth) situated at point quarter from posterior end, followed by ridge. Rostrum proportionately broad distally, with interior angle of 25-30°; length 0.4-0.8 × that of remaining carapace (longer in small specimens), breadth slightly more than half carapace breadth at posterior carapace margin; dorsal surface concave; lateral margin somewhat convex, with 2-4 small spines on distal half. Lateral orbital spine situated very slightly anterior to level of anterolateral spine. Pterygostomian flap anteriorly angular, produced to strong sharp spine, surface with 2 spines on anterior half and another few smaller spines on posterior half.

Sternum: Excavated sternum anteriorly rounded or broad blunt subtriangular, surface with ridge in midline. Sternal plastron nearly as long as broad, somewhat broader posteriorly. Sternite 3 moderately depressed, anterior margin weakly concave, bearing pair of small, often obsolescent submedian spines separated by deep sinus. Sternite 4 with nearly straight anterolateral margin anteriorly produced to spine often with accompanying spine lateral and/or mesial to it, posterolateral margin as long as anterolateral margin. Anterolateral margin of sternite 5 anteriorly rounded, length two-thirds that of posterolateral margin of sternite 4.

Abdomen: Smooth, sparsely setose (with short setae). Somite 1 not ridged transversely. Somite 2 tergite 2.2-2.3 × broader than long; pleuron posterolaterally bluntly angular, lateral margin concave and moderately divergent posteriorly. Pleuron of somite 3 with blunt lateral terminus. Telson slightly less than half as long as broad; posterior plate as long as or slightly longer than anterior plate, posterior margin feebly concave or nearly transverse.

Eye: Elongate, twice as long as broad, overreaching midlength of rostrum; lateral and mesial margins somewhat convex proximally. Cornea not dilated, half as long as remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle slender, 3.8-4.0 × longer than high. Antennal peduncle overreaching cornea. Article 2 with strong distolateral spine. Antennal scale 1.7-1.8 × broader than article 5, distally sharp, overreaching article 5 including distal spine; lateral margin with 1 or 2 small, often obsolete proximal spines. Distal 2 articles each with ventral distomesial spine; article 5 1.4-1.5 × length of article 4, breadth 0.7 × height of antennular ultimate article. Flagellum of 7-12 segments not reaching distal end of P1 merus.

Mxp: Mxp1 with bases distinctly separated. Mxp3 basis with 1 distal denticle (often obsolete) on proximally convex mesial ridge. Ischium with tuft of a few long setae often accompanied by small spine lateral to rounded distal end of flexor margin; crista dentata with 15-17 denticles. Merus 1.5 × longer than ischium, flattish on mesial face; flexor margin sharply ridged, bearing a few small spines at angular midpoint, distolateral spine well developed. Carpus also with welldeveloped distolateral spine and a few extensor marginal spines.

P1: More than 4 × longer than carapace, sparingly setose. Ischium dorsally with strong, curved spine, ventromesially with strong subterminal spine proximally followed by a few small spines. Merus 1.1-1.3 × longer than carapace, ventrally with row of 3 equidistant spines other than large distomesial and distolateral spines, mesially with field of 3 proximal spines, dorsally with a few small spines. Carpus nearly smooth, ventrally with distolateral and distomesial spines; occasionally with a few tubercular processes or small spines on proximal mesial margin and on proximal part of dorsal surface; length 1.2-1.4 × that of merus. Palm subequal to or slightly longer than carpus, massive with convex lateral and mesial margins, length 2.2-2.5 × (males), 2.4-3.2 × (females) breadth. Fingers with feebly incurved tips, not distinctly crossing when closed, gaping in both sexes but weakly so in females; movable finger 0.4-0.6 × as long as palm, opposable margin with subtriangular median process fitting into opposite longitudinal groove on fixed finger when closed.

P2-4: Sparsely setose, moderately compressed mesio-laterally. Meri equally broad on P2-4; length-breadth ratio, 3.9-5.1 on P2, 3.3-4.7 on P3, 2.8-3.9 on P4; dorsal margin with row of spines distinct on P2 and P3, often obsolescent on P4, without spine at distal end; ventrolateral margin ending in distal spine. P2 merus subequal to or slightly longer than P3 merus, 1.2-1.3 × longer than P2 propodus, about as long as carapace; P3 merus subequal to length of P3 propodus; P4 merus 0.8- 0.9 × length of P3 merus, 0.8-0.9 × length of P4 propodus. Carpi subequal, shorter than dactyli (carpus-dactylus length ratio, 0.7 on P2 and P3, 0.6 on P4); carpus-propodus length ratio, 0.4 on P2 and P3, 0.3-0.4 on P4; extensor margin with 2 distal spines, and often small proximal spine. Propodi subequal on P3 and P4, slightly shorter on P2; flexor margin nearly straight, terminating in pair of spines preceded by 5-6 (rarely 4) basally articulated, slender spines, distalmost of these more remote from terminal pair than from distal second. Dactyli proportionately broad, sparsely setose; dactyluscarpus length ratio, 1.4-1.5 on P2, 1.5-1.7 on P3, 1.6-1.8 on P4; dactylus-propodus length ratio, 0.6 on P2-4; flexor margin nearly straight, with 13-15 spines closely arranged (not contiguous) and obliquely directed, ultimate slender, as broad as antepenultimate, penultimate more than 2 × broader than ultimate.

Eggs. Number of eggs carried, 2-11; size, 0.67 mm × 0.75 mm.

REMARKS„ The spination of P1, especially in having three closely arranged spines on the proximal mesial surface of the merus, is rather characteristic among the species of the genus, being shared by U. quinarius , U. dualis n. sp., U. floccus n. sp. and U. lumarius n. sp. Uroptychus quinarius is readily distinguished from the congeners by having 5 instead of 6-8 spines on the carapace lateral margin. In addition, the spination of the P2-4 dactyli is similar in U. quinarius , U. dualis and U. floccus , but the row of dorsal spines on the P2-3 meri is present in U. quinarius , absent in U. dualis and U. floccus . The spination of the P2-4 dactyli is different between U. quinarius and U. lumarius : in U. quinarius , the ultimate flexor spine is slender and the penultimate spine is pronouncedly broad, preceded by slender, obliquely directed, closely arranged spines, whereas in U. lumarius , the slender ultimate spine is preceded by relatively large, subtriangular, loosely arranged and proximally diminishing spines.

The combination of the following characters links U. quinarius to U. vegrandis n. sp.: the carapace lateral margin with 5 well-developed, widely spaced spines, the rostrum with small lateral spines, the antennal articles 4 and 5 each with a distinct distal spine, the antennal scale overreaching the peduncle, and the spination of P2-4. Discriminating characters between these species are given under the remaks of that species (see below).

Figures

FIGURE 220 Uroptychus quinarius n. sp., holotype, ovigerous female 2.7 mm (MNHN-IU-2013-8519). A, carapace and anterior part of abdomen, proximal part of left P1 included,dorsal.B,same,lateral.C, anterior part of sternal plastron,with excavated sternum and basal parts of Mxp1. D, telson.E, left antenna,ventral.F, left Mxp3,proximal part,setae omitted,ventral.G, same,merus and carpus,setae omitted, lateral.H, right P1, dorsal.I, same,proximal part,setae omitted,ventral.Scale bars: 1 mm.

FIGURE 221 Uroptychus quinarius n. sp., holotype, ovigerous female 2.7 mm (MNHN-IU-2013-8519). A, left P2, lateral. B, same, distal part, setae omitted, lateral. C, right P3, setae omitted, lateral. D, same, distal part, setae omitted, lateral. E, right P4, setae omitted, lateral. F, same, distal part, setae omitted, lateral. Scale bars: 1 mm.