Uroptychus empheres Ahyong & Poore, 2004

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 : 200-204

Uroptychus empheres Ahyong & Poore, 2004

Figures 88 , 89

Diptychus australis Henderson, 1885: 420 (part).

Uroptychus australis — Henderson 1888: 179 (part).

Uroptychus empheres — Ahyong & Poore, 2004: 34 , fig. 8.

TYPE MATERIAL — Holotype: Australia, “Andys” Seamount , Tasmania, 800 m, male ( NMV J52864 ). [not examined].

MATERIAL EXAMINED — Indonesia, Kai Islands. KARUBAR Stn CP19, 5°15’S, 133°01’E, 605- 576 m, on gorgonacean, 25.X.1991, 1 ♂ 6.4 mm, 1 ♀ 5.1 mm (MNHN-IU-2014-16442) . Indonesia, off Banda. CHALLENGER Stn 194, 4°31’0”S, 129°57’20”E, 360 fms [659 m], 1 ov. ♀ 7.4 mm ( BMNH 1888:33) [syntype of U. australis ( Henderson, 1885) . Solomon Islands. SALOMON 1 Stn CP1751, 09°10’S, 159°53’E, 749-799 m, 25.IX.2001, 2 ♂ 4.9, 7.3 mm, 1 ov. ♀ 5.8 mm (MNHN-IU-2014-16443) . – Stn CP1839, 10°16’S, 161°40’E, 575-624 m, 05.X.2001, 1 ov. ♀ 6.7 mm (MNHN-IU-2014-16444) . SALOMON 2 Stn CP2213, 7°38.7’S, 157°42.9’E, 495-650 m, 26.X.2004, 1 ♂ 6.5 mm, 1 ♀ 5.5 mm (MNHN-IU-2014-16445) . – Stn CP2214, 7°41.6’S, 157°43.8’E, 550-682 m, 26.X.2004, 1 ov. ♀ 6.4 mm (MNHN-IU-2014-16446) . – Stn DW2238, 06°53’S, 156°21’E, 470- 443 m, 30.X.2004, 1 ♂ 7.3 mm, 1 ov. ♀ 6.2 mm (MNHN-IU-2014-16447) . – Stn CP2245, 7°43.1’S, 156°26.0’E, 582-609 m, 1.XI.2004, 1 ov. ♀ 6.9 mm (MNHN-IU-2014-16448) . – Stn CP2264, 7°52.4’S, 156°51.0’E, 515-520 m, 3.XI.2004, 1 ♂ 8.7 mm (MNHN-IU-2014-16449) . – Stn CP2267, 7°48.0’S, 156°52.0’E, 590-600 m, 4.XI.2004, 1 ov. ♀ 6.9 mm (MNHN-IU-2014-12787) . – Stn CP2269, 7°45.1’S, 156°56.3’E, 768-890 m, 4.XI.2004, 1 ♂ 6.2 mm (MNHN-IU-2014-16450) . – Stn CP2297, 9°08.8’S, 158°16.0’E, 728-777 m, 8.XI.2004, 2 ♂ 5.0, 7.7 mm (MNHN-IU-2014-16451) . Tonga. BORDAU 2 Stn CP1529, 21°13’S, 174°58’W, 688-710 m, 3.VI.2000, 2 ♂ 6.8, 8.1 mm, 2 ov. ♀ 6.0, 8.2 mm (MNHN-IU-2014-12788) . – Stn DW1589, 18°39’S, 173°54’W, 281 m, 13.VI.2000, 1 ♂ 9.0 mm ( MNHN- IU-2014-12789) . – Stn CP1625, 23°28’S, 176°22’W, 824 m, 19.VI.2000, 1 ♂ 4.1 mm, 1 ov. ♀ 7.5 mm, 3 ♀ 4.1-5.6 mm (MNHN-IU-2014-12790) . New Caledonia, Loyalty Ridge. BATHUS 3 Stn DW778, 24°43’S, 170°07’E, 750-760 m, 24.XI.1993, 1 ♂ 5.8 mm (MNHN-IU-2014-16452), 1 ♀ 6.8 mm (MNHN-IU-2014-16453) . – Stn DW792, 23°46’S, 169°49’E, 730-735 m, 26.XI.1993, 1 ov. ♀ 7.3 mm (MNHN-IU-2014-16454) . New Caledonia, Norfolk Ridge. NORFOLK 2 Stn DW2102, 23°56’S, 167°44’E, 700-715 m, 30.X.2003, 1 ov. ♀ 8.4 mm (MNHN-IU-2014-16455) .

DISTRIBUTION„ Tasmania, and now off Banda, Kai Islands, Loyalty Islands, Norfolk Ridge, Tonga and Solomon Islands; 281- 890 m.

SIZE„ Males, 4.1-9.0 mm; females, 4.1-8.4 mm; ovigerous females from 5.8 mm.

DESCRIPTION„ Medium-sized species. Carapace: 1.1 × longer than broad; greatest breadth 1.6-1.7 × distance between anterolateral spines. Dorsal surface feebly convex, with or without feeble depression between gastric and cardiac region; pair of epigastric scales composed of granules occasionally absent. Lateral margins posteriorly convex, with elevated small ridge at anterior end of branchial region, followed by row of oblique short ridges so as to be seen as granulose in dorsal view; anterolateral spines small, reaching or slightly falling short of tip of lateral orbital spine. Rostrum relatively narrow and elongate, with interior angle of 24-28°, straight horizontal or feebly deflected ventrally; about half or slightly less than half as long as remaining carapace, breadth slightly more than half carapace breadth measured at posterior carapace margin; dorsal surface flattish. Lateral limit of orbit acuminate or ending in very small spine laterally followed by oblique margin leading to anterolateral spine. Pterygostomian flap smooth on surface, anteriorly roundish with very small spine.

Sternum: Excavated sternum anteriorly ending in small acute process between bases of Mxp1, surface with small spine in center. Sternal plastron slightly broader than or as broad as long, with lateral extremities divergent posteriorly. Sternite 3 well depressed, anterior margin deeply emarginate, bearing 2 submedian spines flanking narrow median notch. Sternite 4 having anterolateral margin somewhat convex and denticulate, anteriorly ending in short, blunt spine; posterolateral margin less than half length of anterolateral margin. Anterolateral margin of sternite 5 convex, slightly longer than posterolateral margin of sternite 4.

Abdomen: Tergites smooth and glabrous. Somite 1 with rounded transverse ridge. Somite 2 tergite 2.3-2.7 × broader than long; pleural lateral margin concavely divergent posteriorly, rounded on posterolateral terminus. Pleuron of somite 3 posterolaterally blunt. Telson three-fifths as long as broad; posterior plate about 1.5 × longer than anterior plate, posterior margin slightly concave or distinctly emarginate.

Eye: Broad relative to length (1.4-1.5 × longer than broad), slightly broadened distally, overreaching midlength of rostrum. Cornea slightly dilated, about as long as remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle 2.2-2.5 × longer than high. Antennal peduncle slightly overreaching cornea. Article 2 with very small distolateral spine. Antennal scale 1.3-1.8 × as broad as article 5, reaching or slightly overreaching distal end of article 5. Distal 2 articles unarmed; article 5 2.2-2.8 × length of article 4, breadth barely or nearly half height of ultimate antennular article. Flagellum of 15-17 segments not reaching distal end of P 1 merus.

Mxp: Mxp1 with bases very close to each other. Mxp3 barely setose on lateral surface. Basis with 1-3 denticles on mesial ridge. Ischium with 13-18 denticles on crista dentata, flexor margin not rounded distally. Merus 2.0-2.2 × longer than ischium, thick mesiolaterally, unarmed; flexor margin roundly ridged, not cristate. Carpus unarmed.

P 1: Slender, unarmed except for very small distodorsal spine of ischium, smooth on dorsal surface, granulose on ventral surface (not on fingers) in large specimens; length 5.0-5.4 × that of carapace. Merus 1.1-1.3 × longer than carapace, ventromesial and ventral surface with row of short spines often tubercle-like or obsolescent. Carpus 1.2-1.4 × longer than merus. Palm 3-5 × longer than broad (slightly more slender in females), 0.8-0.9 × length of carpus, ventral surface granulose. Fingers proportionately broad, terminating in small incurved spine and distally crossing when closed,; movable finger with broad two-toothed proximal process, length about half that of palm; fixed finger having opposable margin with low prominence distal to position of opposite process on movable finger.

P 2-4: With long setae sparsely or sparingly. Meri subequal in length on P 2 and P 3 or slightly longer on P 3 than on P 2, shortest on P 4 ( P 4 merus 0.6 × length of P 3 merus), moderately compressed mesio-laterally, unarmed; length-breadth ratio, 5.0-5.2 on P 2, 4.8-5.3 on P 3, 3.6-4.5 on P 4; P 2 merus 0.8-1.0 × length of carapace, 1.2-1.3 × length of P 2 propodus; P 3 merus 1.1-1.2 × length of P 3 propodus; P 4 merus much narrower than P 2-3 meri, length 0.8-0.9 × that of P 4 propodus. Carpi subequal in length on P 2 and P 3 or slightly longer on P 3 than on P 2 and shortest on P 4; carpus-propodus length

ratio, 0.5-0.6 on P 2, 0.5 on P 3 and P 4. Propodus longest on P 3, subequal on P 2 and P 4 or shorter on P 4 than on P 2; flexor margin straight, with pair of terminal spines slightly proximal to juncture with dactylus, preceded by row of 6-9 spines on P 2, 5-7 spines on P 3, 4-5 spines on P 4, distalmost of these unpaired spines equidistant between pair of spines and distal second spine. Dactyli about one-third length of propodus on P 2 and P 3, 0.4-0.5 × on P 4; 0.6-0.7 × length of carpi on P 2-4; strongly curved at proximal third; flexor margin with 8-9 obliquely directed, loosely arranged, sharp spines, ultimate spine distinctly longer and broader than penultimate, penultimate as broad as antepenultimate and close to ultimate, antepenultimate more remote from penultimate than from distal quarter.

Eggs. Number of eggs carried 3-25; size, 1.30 mm × 1.50 mm - 1.67 mm × 1.92 mm.

REMARKS — As mentioned under U. australis (see above), the ovigerous female, one of the syntypes of U. australis from Challenger Stn 194, is referred to U. empheres .

Uroptychus empheres is so closely related to U. australis ( Henderson, 1885) and U. terminalis n. sp. described below, in the shape of the carapace and in having the much smaller P 4 that Henderson (1885, 1888) could not discriminate among these three species, which are actually mixed in the type material of U. australis (see above under U. australis ). Uroptychus empheres is readily distinguished from U. australis by the flexor marginal spines of the P 2-4 dactyli that are obliquely directed instead of orientated parallel to the margin. The relationships between U. empheres and U. terminalis are discussed under the remarks of the latter species. The species is also very close to U. comptus in nearly all features. Their relationships were discussed by Ahyong & Poore (2004).

Figures

FIGURE 88 Uroptychus empheres Ahyong & Poore, 2004,male 5.8 mm (MNHN-IU-2014-16452). 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, right Mxp3, merus and carpus, lateral. G, left P1, proximal articles omitted. H, right P2, lateral.I, same,distal part,setae omitted, lateral. Scale bars: 1 mm.

FIGURE 89 Uroptychus empheres Ahyong & Poore,2004,ovigerous female 7.4 mm (BMHN 1888:33),Challenger Stn 194.A, carapace and anterior part of abdomen,dorsal.B, same,lateral.C, excavated sternum with basal parts of Mxps 1-3. D, anterior part of sternal plastron.E, left antenna, ventral.F, left P2, lateral.G, same,propodus, mesial.H, left P3, lateral.I, right P3, propodus and dactylus, lateral.J, same, dactylus, lateral. K, right P4, propodus and dactylus,lateral. Scale bars:1 mm.