Uroptychus yokoyai Ahyong & Poore 2004
Creators: name: Baba, Keiji
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Chirostylidae
Uroptychus
Uroptychus yokoyai

description: Uroptychus yokoyai Ahyong & Poore, 2004
Figures 284, 306H
Uroptychus yokoyai Ahyong & Poore, 2004: 79, fig. 25. — Poore et al. 2011: 330, pl. 8, fig. E.
TYPE MATERIAL — Holotype: Australia, Gifford Guyot, E of Brisbane, 26°44.27’S, 159°28.93’E, 306 m, male (AM P65827). [not examined].
MATERIAL EXAMINED — Philippines. MUSORSTOM 1 Stn CP60, 14°05’N, 120°19’E, 129- 124 m, 27.III.1976, 2 ♂ 2.6, 3.4 mm, 4 ov. ♀ 2.6-3.3 mm, 2 ♀ 2.5, 3.1 mm (MNHN-IU-2014-17025). MUSORSTOM 3 Stn CP131, 11°37’N, 121°43’E, 120-122 m, with Chrysogorgiidae gen. sp. (Calcaxonia), 5.VI.1985, 5 ♂ 2.5-3.7 mm, 4 ov. ♀ 3.3-3.9 mm, 2 ♀ 2.9, 3.3 mm (MNHN-IU-2014-17026). Vanuatu. MUSORSTOM 8 Stn CP1017, 17°52.80’S, 168°26.20’E, 294-295 m, 27.IX.1994, 1 ♂ 3.9 mm (MNHN-IU-2014-17027). – Stn DW964, 20°19.60’S, 169°49.00’E, 360-408 m, 21.IX.1994, 1 ♀ 3.0 mm (MNHN-IU-2014-17028). – Stn CP1133, 15°38.83’S, 167°03.06’E, 174-210 m, 11.X.1994,2 ov. ♀ 2.9,3.0 mm, 1 ♀ 2.3 mm (MNHN-IU-2014-17029). Santo Stn AT07, 15°38’S, 167°02’E, 180-223 m, 15.IX.2006, 1 ♀ 3.6 mm (MNHN-IU-2014-17030). – Stn AT17, 15°39.9’S, 167°02.0’E, 267-270 m, 21.IX.2006, 1 ♀ 3.1 mm (MNHN-IU-2014-17031). – Stn AT76, 15°38.7’S, 167°03.6’E, 105-135 m, 10.X.2006, 1 ♀ 3.2 mm (MNHN-IU-2014-17032). New Caledonia. LAGON Stn DW1151, 19°01’S, 163°27’E, 270-280 m, 28.X.1989, 1 ♂ 2.8 mm (MNHN-IU-2014-17034). – Stn DW389, 22°44’ S, 167°04’E, 274- 274 m, 22.I.1985, 1 ♀ 3.0 mm (MNHN-IU-2014-17035). – Stn DW396, 22°40’S, 167°09’E, 280-284 m, 23.I.1985, 1 ♀ 3.2 mm (MNHN-IU-2014-17036). New Caledonia, South of Chesterfield Islands. MUSORSTOM 5 Stn CP254, 25°10.29’S, 159°53.07’E, 280-290 m, with coral,?Octocorallia, 7.X.1986, 1 ♂ 3.2 mm (MNHN-IU-2014-17037). – Stn DW273, 24°43.02’S, 159°43.26’E, 290 m, with Chrysogorgiidae gen. sp. (Calcaxonia), 9.X.1986, 1 ♂ 4.1 mm (MNHN-IU-2014-17038). – Stn CP289, 24°01.50’S, 159°38.40’ E, 273 m, 10.X.1986, 1 ov. ♀ 3.4 mm (MNHN-IU-2014-17039). EBISCO, CP2494, 24°45’S, 159°42’E, 348-354 m, 06.X.2005, 1 ov. ♀ 3.6 mm (MNHN-IU-2014-17033). New Caledonia, Loyalty Ridge. MUSORSTOM 6 Stn DW399, 20°41.80’S, 167°00.20’E, 282 m, with Chrysogorgiidae gen. sp. (Calcaxonia), 14.II.1989, 1 ♂ 2.5 mm, 1 ov. ♀ 2.8 mm (MNHN-IU-2014-17040). – Stn CP400, 20°42.18’S, 167°00.40’E, 270 m, with Chrysogorgiidae gen. sp. (Calcaxonia), 14.II.1989, 2 ov. ♀ 2.9, 3.7 mm (MNHN-IU-2014-17041). – Stn DW417, 20°41.80’S, 167°03.65’E, 283 m, 16.II.1989, 1 spec. (sex indet.) 1.6 mm (MNHN-IU-2014-17042). New Caledonia, Norfolk Ridge. LITHIST Stn CP10, 24°48.4’S, 168°09.0’ E, 245-261 m, 11.VIII.1999, 1 ♂ 2.6 mm, 4 ov. ♀ 2.3-3.2 mm, 1 ♀ 2.6 mm (MNHN-IU-2014-17043). – Stn DW11, 24°46.7’S, 168°08.3’E, 254-283 m, 11.VIII.1999, 1 ♂ 2.9 mm, 1 ov. ♀ 2.7 mm (MNHN-IU-2014-17044). – Stn DW13, 23°45.0’S, 168°16.7’E, 400 m, 12.VIII.1999, 1 ♂ 2.1 mm (MNHN-IU-2014-17045). BATHUS 3 Stn CP804, 23°41.40’S, 168°00.42’E, 244-278 m, 27.XI.1993, 1 ♀ 3.0 mm (MNHN-IU-2014-17046). SMIB 4 Stn DW41, 24°44’S, 168°09’E, 230-235 m, 08.III.1989, 1 ♀ 2.3 mm (MNHN-IU-2014-17047). – Stn DW45, 24°45’S, 168°08’E, 245-260 m, 08.III.1989,with Chrysogorgiidae gen.sp.(Calcaxonia),3 ov. ♀ 2.2-2.6 mm (MNHN-IU-2014-17048). – Stn DW47, 24°46’ S, 168°08’E, 250-280 m, 08.III.1989,2 ov. ♀ 2.4, 2.5 mm (MNHN-IU-2014-17049). SMIB 5, Banc Alis, 250 m, rock, 1.IX.1985, 1 ♂ 3.3 mm,1 ov. ♀ 3.2 mm (MNHN-IU-2014-17050). – Stn DW75, 23°41’S, 168°01’E, 250-270 m, 07.IX.1989, 1 ♀ 2.0 mm (MNHN-IU-2014-17051). – Stn DW95, 23°00’S, 168°19’E, 140-200 m, 14.IX.1989, 1 ♂ 2.3 mm,2 ov. ♀ 2.4, 2.5 mm (MNHN-IU-2014-17052). – Stn DW97, 23°02’S, 168°18’E, 240-300 m, 14.IX.1989, 1 ♂ 3.1 mm, 1 ov. ♀ 3.3 mm (MNHN-IU-2014-17053). – Stn DW101, 23°21’S, 168°05’E, 285- 270 m, 14.IX.1989, 1 ov. ♀ 2.3 mm, 1 ♀ 2.8 mm (MNHN-IU-2014-17054). SMIB 8 Stn DW155, 24°45.7’S, 168°08.2’E, 257-262 m, 28.I.1993, 2 ♂ 2.5, 2.6 mm, 1 ov. ♀ 2.8 mm, 2 ♀ 2.7, 2.8 mm (MNHN-IU-2014-17055); 2 ov. ♀ 2.5, 2.7 mm (MNHN-IU-2014-17056). – Stn DW157, 24°45.64’S, 168°08.23’E, 251-255 m, 28.I.1993, 1 ov. ♀ 2.5 mm (MNHN-IU-2014-17057). – Stn DW159, 24°45.8’S, 168°08.2’E, 241-245 m, 28.I.1993, 2 ♂ 2.5, 2.7 mm (MNHN-IU-2014-17058). NORFOLK 1 Stn DW1675, 24°45’S, 168°09’E, 231-233 m, 22.VI.2001, 3 ov. ♀ 2.7-3.1 mm, 2 ♀ 2.8, 2.8 mm (MNHN-IU-2014-17059). – Stn CP1676, 24°43’S, 168°09’E, 227-232 m, 22.VI.2001, 4 ♂ 2.5-3.3 mm, 4 ov. ♀ 2.3-2.8 mm, 1 ♀ 3.1 mm (MNHN- IU-2014-17060). – Stn CP1677, 24°43’S, 168°10’E, 233-259 m, 22.VI.2001, with coral,Hexacorallia?, 5 ♂ 2.3-2.9 mm, 10 ov. ♀ 2.1-3.0 mm, 1 ♀ 2.9 mm (MNHN-IU-2014-17061). – Stn CP1681, 24°44’S, 168°08’E, 240- 228 m, 22.VI.2001, with Chrysogorgiidae gen. sp. (Calcaxonia), 1 ♂ 2.9 mm, 3 ov. ♀ 2.3-2.8 mm (MNHN-IU-2014-17062). – Stn CP1682, 24°42’S, 168°09’E, 331-379 m, 22.VI.2001, 1 ov. ♀ 2.8 mm (MNHN-IU-2014-17063). – Stn CP1683, 24°44’S, 168°07’E, 248-272 m, 22.VI.2001, 1 ♂ 3.1 mm, 3 ov. ♀ 2.7-2.8 mm (MNHN-IU-2014-17064). – Stn CP1714, 23°22’S, 168°03’E, 257-269 m, 26.VI.2001, 1 ♂ 3.2 mm (MNHN-IU-2014-17065). NORFOLK 2 Stn DW2093, 24°44’S, 168°08’E, 230 m, 29.X.2003, 1 ♂ 2.9 mm (MNHN-IU-2014-17066). – Stn CP2096, 24°43.91’S, 168°08.88’E, 230-240 m, 29.X.2003, 4 ♂ 2.6-2.9 mm, 4 ov. ♀ 2.3-2.8 mm, 2 ♀ 2.5, 2.6 mm (MNHN-IU-2014-17067). – Stn DW2158, 22°41.40’S, 167°14.01’E, 265-283 m, 6.XI.2003, 1 ♂ 2.4 mm (MNHN-IU-2014-17068). BERYX 11 Stn CP16, 24°47’S, 168°09’E, 240-250 m, 16.X.1992, 1 ov. ♀ 2.3 mm (MNHN-IU-2014-17069). – Stn CP17, 24°48’S, 168°09’E, 250-270 m, 16.X.1992, 1 ♂ 2.3 mm (MNHN-IU-2014-17070). – Stn DW18, 24°48’S, 168°09’E, 250-270 m, 16.X.1992, 1 ov. ♀ 2.6 mm, 1 ♀ 2.7 mm (MNHN-IU-2014-17071), 1 ♂ 2.6 mm, 1 ov. ♀ 2.2 mm (MNHN- IU-2014-17072). – Stn CP25, 24°43.52’S, 168°08.52’E, 230-235 m, 17.X.1992, 4 ov. ♀ 3.0- 3.1 mm, 1 ♀ 2.7 mm (MNHN-IU-2014-17073). BIOCAL Stn DW65, 24°48’S, 168°09’E, 245-275 m, 3.IX.1985, 1 ov. ♀ 2.3 mm (MNHN-IU-2014-17074). CHALCAL 2 Stn CP19, 24°42.85’S, 168°09.73’E, with Chrysogorgiidae gen. sp. (Calcaxonia), 271 m, 27.X.1986, 1 ov. ♀ 2.6 mm (MNHN-IU-2014-17075), 2 ♂ 2.4, 2.6 mm, 11 ov. ♀ 2.1-2.6 mm (MNHN- IU-2014-17076). – Stn DW70, 24°46.0’ S, 168°09.0’E, 232 m,with coral Chrysogorgiidae (Calcaxonia), 27.X.1986, 3 ♂ 2.3-2.9 mm, 4 ov. ♀ 2.4-2.7 mm, 1 ♀ 3.1 mm (MNHN-IU-2014-17077). – Stn DW71, 24°42.26’S, 168°09.52’E, 230 m, with Chrysogorgiidae gen. sp. (Calcaxonia), 27.X.1986, 1 ♂ 2.1 mm, 10 ov. ♀ 2.0- 2.6 mm (MNHN-IU-2014-17078). MUSORSTOM 4 Stn CP152, 19°05’S, 163°23’E, 228 m, 14.IX.1985, 1 ♀ 3.0 mm (MNHN-IU-2014-17079). – Stn DW209, 22°41.8’S, 167°09.1’E, 310-315 m, 28.IX.1985, 1 ♀ 2.8 mm (MNHN-IU-2014-17080). New Caledonia, Hunter-Matthew Islands. VOL- SMAR Stn DW39, 22°20’S, 168°44’E, 280-305 m, 08.VI.1989, 3 ♂ 2.5-2.9 mm, 6 ov. ♀ 2.7-3.3 mm (MNHN-IU-2014-17081). – Stn DW41, 22°19’S, 168°41’E, 195-250 m, 08.VI.1989, 1 ♂ 3.1 mm (MNHN-IU-2014-17082), 1 ♂ 3.1 mm, 1 ov. ♀ 3.0 mm (MNHN-IU-2014-17083), 1 ♂ 3.2 mm (MNHN- IU-2014-17084). – Stn DW42, 22°17’S, 168°42’E, 340-400 m, 08.VI.1989, 1 ♂ 3.0 mm, 1 ov. ♀ 3.3 mm (MNHN-IU-2014-17085). Tonga. BORDAU 2 Stn CP1626, 23°20’S, 176°16’W, 220-249 m, 19.VI.2000, 1 ♀ 2.7 mm (MNHN-IU-2014-17086).
DISTRIBUTION„ Previously known from Tasman Sea, in 295-306 m; now from the Philippines, Vanuatu, New Caledonia, south of the Chesterfield Islands, Norfolk Ridge, the Hunter-Matthew Islands, and Tonga, in 105- 573 m.
SIZE„ Males, 2.1-4.1 mm; females, 2.0- 4.5 mm; ovigerous females from 2.0 mm; sex indet., 1.6 mm.
DIAGNOSIS„ Small species. Carapace slightly broader than long; greatest breadth 1.3 × distance between anterolateral spines. Dorsal surface smooth and glabrous, slightly convex from anterior to posterior. Lateral margins usually strongly convex, particularly on posterior two-thirds; anterolateral spine small and subequal to lateral orbital spine; pronounced spine at anterior end of branchial margin followed by additional 0-3 (usually 2) small spines. Rostrum very broad, nearly equilateral triangular, with interior angle of 50-57°; breadth more than two-thirds carapace breadth at posterior carapace margin; dorsal surface concave. Lateral orbital spine very close to anterolateral spine. Pterygostomian flap smooth on surface, anterior margin roundish with small or obsolescent spine. Excavated sternum anteriorly produced to small sharp spine, smooth on surface. Sternal plastron 1.2-1.3 × broader than long, lateral extremities convexly divergent posteriorly, sternites 6 and 7 equally broad. Sternite 3 strongly depressed; anterior margin deeply or shallowly semicircular, occasionally medially deeply emarginate, with no submedian spines; sternite 4 with anterolateral margin relatively long, convex and anteriorly roundish; posterolateral margin one-quarter length of anterolateral margin; anterolateral margin of sternite 5 more than 3 × longer than posterolateral margin of sternite 4. Abdomen smooth and glabrous; somite 1 without transverse ridge; somite 2 tergite 3.1-3.4 × broader than long; pleuron posterolaterally blunt, lateral margin feebly concave, strongly divergent posteriorly; pleuron of somite 3 with blunt posterolateral terminus; telson 0.7-0.8 × as long as broad; posterior plate trianguloid, with rounded posterior margin, length subequal to greatest breadth, 2.3-3.0 × that of anterior plate. Eye reaching or slightly overreaching apex of rostrum, 2 × longer than broad, with subparallel mesial and lateral margins, cornea half as long as remaining eyestalk. Ultimate antennular article about 2 × as long as high. Antennal peduncle relatively slender, not reaching corneal margin; article 2 without distinct distolateral spine; antennal scale reaching or slightly overreaching midlength of article 5; distal 2 articles each with distomesial spine, that of article 4 often obsolescent; article 5 2.0-2.2 × longer than article 4, breadth 0.4 × height of ultimate antennular article; flagellum of about 20 segments overreaching distal end of P1 merus. Mxp1 with bases very close to each other. Mxp3 basis with obsolescent denticles on mesial ridge; ischium having flexor margin not rounded distally, crista dentata with about 20 denticles; merus 2.4-2.9 × longer than ischium, flexor margin not cristiform but rounded; distolateral spine distinct, very small or obsolete; carpus with small distolateral spine. P1 with long setae on fingers and distal portion of palm, glabrous elsewhere; ischium with strong, curved dorsal spine, subterminal spine on ventromesial margin obsolescent; merus 1.3-1.5 × longer than carapace, proximally and distally narrowed especially in small specimens (hence representing reverse shape of “bowling pin”); carpus proximally narrowed, 1.4-1.6 × (males), 1.6-1.7 × (females) longer than merus, finely granulose on mesial and lateral faces; palm 3.0-3.4 (males), 4.4-5.3 × (females) longer than broad, subequal to or slightly shorter than carpus; laterally and often dorsally with fine tubercles; fingers ending in incurved tip, crossing when closed; fixed finger with convex, finely dentate cutting edge; opposing margin of movable finger with disto-proximally broad proximal process low in females and small males, often sharply pointed (distal margin perpendicular to opposable margin) in males; movable finger 0.4 × length of palm in both sexes.P2-4 slender, bearing sparse long setae, especially on carpi and meri, unarmed on meri and carpi; meri successively shorter posteriorly (P3 merus 0.9 × length of P2 merus, P4 merus 0.8-0.9 × length of P3 merus), equally broad on P2-4; length-breadth ratio, 6.0 on P2, 5.0 on P3, 4.0-5.0 on P4; P2 merus subequal to or slightly longer than carapace, 1.5-1.6 × length of P2 propodus; P3 merus 1.3 × length of P3 propodus; P4 merus 1.1 × length of P4 propodus; carpi subequal or successively slightly shorter posteriorly, more than half as long as propodus on P2 and P3, nearly half as long on P4, usually with long setae distally; propodi subequal in length on P3 and P4, slightly shorter on P2, flexor margin concavely curving, ending in pair of spines preceded by 7 or 8 slender spines on P2 and P3, 6 spines on P4; dactyli slightly shorter than carpi (dactylus-carpus length ratio, 0.7-0.8 on P2, 0.8-0.9 on P3 and P4), about half or slightly less than half length of propodi, moderately curved; flexor margin with 9-10 (usually 10) subtriangular spines somewhat inclined and proximally diminishing.
Color. The female (3.6 mm) (MNHN-IU-2014-17030) from SANTO Stn AT07 was illustrated in Poore et al. (2011). Base color pale pink, cephalothorax and abdomen more pinkish along midline, abdominal pleura translucent.
Eggs. Number of eggs carried, 4 (in small specimens)-20 (in large specimen); size, 0.93 mm × 1.01 mm - 0.99 mm × 1.01 mm.
PARASITES„ The male from MUSORSTOM 5 Stn CP254 (MNHN-IU-2014-17037) bears a rhizocephalan externa on the abdomen.
REMARKS„ The species strongly resembles Uroptychus latirostris Yokoya, 1933 in the carapace ornamentation, in having a broad triangular rostrum, and in having no distinct submedian spines on the sternite 3 anterior margin, but it is distinctive in the following particulars: The P1 merus is proximally narrowed, representing a unique shape like a bowling pin, especially in small specimens; the anterolateral spine of the carapace is very close to instead of somewhat distant
from the lateral orbital spine; and the posterior plate of the telson is elongate and narrowed posteriorly (hence, trianguloid) instead of semicircular.
This is one of the most common species in the vicinity of New Caledonia, taken at 58 sampling stations.
description: Published as part of Baba, Keiji, 2018, Chirostylidae of the Western and Central Pacific: Uroptychus and a new genus (Crustacea: Decapoda: Anomura), pp. 1-612 in Mémoires du Muséum national d'Histoire naturelle 212 on pages 561-565, DOI: 10.5281/zenodo.3760976