Uroptychus joloensis Van Dam, 1939

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 : 243-245

Uroptychus joloensis Van Dam, 1939

Figure 305 E-G

Uroptychus joloensis Van Dam, 1939: 395 ,figs 2, 2a,2b, 2c. — Ahyong & Baba 2004: 58 , fig.1. — Baba 2005:39, 227.— Baba et al. 2008: 35. — Poore

et al. 2011: 328, pl. 6, fig. I. — McCallum & Poore 2013: 164, fig. 12D.

Uroptychus kudayagi Miyake, 1961: 237 , figs 1, 2. — 1982: 143, pl. 48, fig. 2. — Minemizu 2000: 165,unnumbered fig. — Kawamoto & Okuno 2003:

97, unnumbered fig.

TYPE MATERIAL — Holotype: Philippines, Jolo Sea , 37.8-56.7 mn male ( ZMUC). [not examined].

MATERIAL EXAMINED — Philippines. MUSORSTOM 1 Stn CP60, 14°05’N, 120°19’E, 129-124 m, 27.III.1976, 1 ♂ 4.9 mm, 1 ov. ♀ 4.5 mm (MNHN-IU-2014-16585) . MUSORSTOM 3 Stn CP134,12°01’N, 121°57’E,92-95 m, 5.VI.1985, 1 ♂ 3.3 mm (MNHN-IU-2014-16586) . Solomon Islands. SALOMON 1 Stn CP1831, 10°12.1’S, 161°19.2’E, 135-325 m, 5.X.2001, 1 ♂ 2.7 mm (MNHN-IU-2014-16587) . Vanuatu. GEMINI Stn DW48, 21°00’S, 170°04’E, 200-150 m, 04.VII.1989, 1 ♂ 2.5 mm, 1 ov. ♀ 3.1 mm (MNHN-IU-2014-16588) . MUSORSTOM 8 Stn CP1131, 15°38.41’S, 167°03.52’E, 140-175 m, 11.X.1994, 1 ♂ 3.0 mm (MNHN-IU-2014-16589) ; 2 ov. ♀ 2.9, 3.0 mm (MNHN-IU-2014-16590) . – Stn CP1133, 15°38.83’S, 167°03.06’E, 174-210 m, 11.X.1994, 1 ♀ 2.8 mm (MNHN-IU-2014-16591) . – Stn CP1077, 16°04.00’S, 167°06.09’E, 180-210 m, 5.X.1994, 1 ♂ 2.7 mm (MNHN- IU-2014-16592) . – Stn CP1071, 15°36.63’S, 167°16.34’E, 180-191 m, 4.X.1994, 1 ♂ 3.3 mm (MNHN-IU-2014-16593) . – Stn CP961, 20°18.50’S, 169°49.90’E, 100-110 m, 21.IX.1994, 1 ov. ♀ 3.2 mm, 1 ♀ 2.0 mm (MNHN-IU-2014-16594) . Santo Stn AT04, 15°32.9’S, 167°13.3’E, 97-101 m, 15.IX.2006, 1 ov. ♀ 3.0 mm (MNHN-IU-2014-16595) . – Stn AT06, 15°38’S, 167°02’E, 140-167 m, 15.IX.2006, 1 ♂ 3.5 mm, 2 ov. ♀ 3.2, 3.8 mm, 1 ♀ 3.2 mm (MNHN-IU-2014-16596) . – Stn AT17, 15°40’S, 167°02’E, 267-270 m, 21.IX.2006, 1 ♂ 3.2 mm (MNHN-IU-2014-16597) . – Stn AT22, 15°32.3’S,

167°16.0’E, 180-227 m, 22.IX.2006, 1 ov. ♀ 3.7 mm ( MNHN-IU-2014-16598 ). Wallis and Futuna Islands. MUSORSTOM 7 CP498, 14°19’S, 178°03’W 105-160 m, 10.V.1992, on Chironephthya sp. ( Nidaliidae : Alcyonacea ), 4 ov. ♀ 2.5-2.8 mm (MNHN-IU-2014-16599, MNHN-IU-2014-16600, MNHN- IU-2014-16601, MNHN-IU-2014-16602 ). Fiji Islands. MUSORSTOM 10 CP1364, 18°11.9’S, 178°34.5’E, 80-86 m, 15.VIII.1998, 1 ov. ♀ 3.2 mm ( MNHN- IU-2014-16603) .

DISTRIBUTION„ Previously known from Jolo Sea, Kai Islands, Timor Sea and northwestern Australia in 37.8-142 m; and under the name U. kudayagi Miyake, 1961 , from Japan (eastern Sagami Bay, west coast of Kyushu, southern Kii Peninsula, Shizuoka, and Okinawa), in 20- 80 m. The present material was taken from the Philippines, Solomon Islands, Vanuatu, Wallis and Futuna Islands, and Fiji Islands, in 80- 325 m. Additional material was collected from the southern coast of Papua New Guinea, in 25 m (see below under the remarks).

SIZE„ Males, 2.7-4.9 mm; females 2.0- 4.5 mm; ovigerous females from 2.5 mm.

DIAGNOSIS — Small species. Carapace smooth on surface, somewhat broader than long, greatest breadth about twice distance between anterolateral spines. Lateral margins feebly convexly divergent posteriorly; anterolateral spine situated closely lateral to and overreaching smaller lateral orbital spine; 2 spines about at anterior third (anterior one occasionally very small, vestigial or even obsolete, posterior one larger), followed by ridge along remaining margin. Rostrum triangular, with interior angle of 22-25°, lateral margin with small spine often obsolete, dorsal surface concave, breadth less than half carapace breadth at posterior carapace margin. Pterygostomian flap anteriorly angular, ending in sharp spine. Excavated sternum anteriorly subtriangular, with cristate ridge in midline; sternal plastron slightly longer than broad, with subparallel lateral extremities; sternite 3 having anterior margin very weakly concave, with deep median sinus usually U-shaped, flanked by small incurved spine; sternite 4 with anterolateral margin 1.5 × length of posterolateral margin; anterolateral margins of sternite 5 slightly convexly subparallel, slightly longer than posterolateral margin of sternite 4. Abdominal somite 1 without transverse ridge; somite 2 tergite 2.2-2.4 × broader than long; pleural lateral margins feebly or somewhat concave, subparallel or somewhat divergent posteriorly, posteriorly blunt; pleuron of somite 3 laterally rounded. Telson about half as long as broad; posterior plate 1.4-1.8 × longer than anterior plate, posterior margin roundish. Eyes elongate, distally narrowed, barely reaching apex of rostrum. Ultimate antennular article 2.5 × longer than high. Article 2 of antenna with sharp lateral spine; antennal scale terminating in midlength of article 5; articles 4 and 5 each with distinct distoventral spine, article 5 1.2-1.4 × longer than article 4, breadth 0.6-0.7 × height of ultimate antennular article; flagellum of 6-9 segments not reaching distal end of P1 merus. Mxp1 with bases separated from each other. Mxp3 sharply ridged along flexor margins of ischium and merus; basis with obsolescent denticles on proximal part of mesial ridge; ischium with small spine lateral to rounded distal end of flexor margin, crista dentata with obsolescent denticles; merus about twice longer than ischium, with distolateral spine and 1 or 2 small spines distal to midlength of flexor margin; carpus with distolateral spine and often with small spine on proximal lateral surface. P1 slender, subcylindrical, bearing soft fine setae; 6.2-6.4 × (males), 5.7-7.0 × (females) longer than carapace; ischium dorsally with 2 spines (distal one well-developed and sharp, proximal one small), ventromesially with short, blunt subterminal spine; merus 1.3-1.4 × longer than carapace, with a few small spines on mesio-proximal part of ventral surface; carpus 1.3-1.4 × longer than merus; palm subequal to or slightly longer than carpus; fingers slightly incurved; movable finger 0.3-0.4 × length of palm. P2-4 well compressed mesio-laterally; meri subequal in breadth on P2-4; P2 merus 0.8-0.9 × length of carapace, 1.1-1.2 × length of P2 propodus; P3 merus 0.9 × length of P2 merus, 0.9 × length of P3 propodus; P4 merus 0.9-1.0 × length of P3 merus, 0.8 × length of P4 propodus; carpi subequal, each less than half length of propodus; propodal flexor margin with pair of distal spines only; dactyli longer than carpi (dactyluscarpus length ratio, 1.0-1.1 on P2, 1.1-1.2 on P3, 1.2 on P4), flexor margin with 6 or 7 loosely arranged spines, ultimate slender, penultimate, antepenultimate and often distal quarter prominent, remaining 2 or 3 diminishing proximally, proximal-most somewhat inclined.

Eggs. Number of eggs carried up to 18; size, 0.65 mm × 0.69 mm - 0.9 mm × 1.1 mm.

COLOR — Base color translucent white, reddish on anterior part of carapace (around rostrum, including antennule and antenna) and around juncture between P1 palm and fingers (ov. ♀ 3.0 mm, MNHN-IU-2014-16595 [= Poore et al. 2011: pl. 6, fig. I]); additional red spot at juncture between P1 merus and carpus (specimens from Papua New Guinea, see below under the remarks); red spot absent from P1 (ov. ♀, MNHN-IU-2014-16602; McCallum & Poore, 2013: fig. 12D).

REMARKS — The species is characterized by the carapace lateral margin with two spines about at distal third (the distal of which is often obsolete), the antennal articles 4 and 5 each bearing a strong distal spine, the antennal scale barely reaching the end of the antennal article 5 (usually terminating in the midlength of this article) and the eyes distally narrowed. As noted by Baba et al. (2009), Uroptychus joloensis resembles U. zezuensis in morphology, coloration and habitat preference (see below under U. zezuensis ).

The material reported under U. kudayagi from Japan (Miyake 1961, 1982; Minemizu 2000; Kawamoto & Okuno 2003) bears red spots at junctures between the P1 merus and carpus, and between the palm and fingers, in addition to another red spot around eyes including the rostrum. Specimens identical with this material (1 male 2.3 mm, 1 ov. female 2.1 mm, 2 eggs 0.82 × 0.86 mm, QM W25105), taken at 25 m, Bootless Bay, Port Moresby, Papua New Guinea, were made available, along with a photograph through Peter J.F. Davie ( Figure 305G ). On the other hand, the spots on P1 are totally absent in one of the specimens from the Wallis and Futuna Islands (MNHN-IU-2014-16602) as well as in the specimen from Western Australia ( McCallum & Poore 2013: fig. 12D). The specimen from Vanuatu (MNHN-IU-2014-16595) has the spot only between the palm and fingers ( Poore et al. 2011: pl. 6, fig. I). Inasmuch as no morphological differences are found between all of these forms of different color, these are treated as identical. However, it is not unlikely that the color differences may be validated for species discrimination by molecular data, as has been done for some species of Galathea ( Macpherson & Robainas-Barcia 2015) .

According to Minemizu (2000) and Kawamoto & Okuno (2003), this species is found among branches of alcyonacean corals, usually Siphonogorgia dofleini , rarely S. dispacea (Nidaliidae) . The red spots of the animal resemble the color pattern of the host’s polyps. One of the specimens from MUSORSTOM 7 Stn CP498 (MNHN-IU-2014-16601) was found on Chironephthya sp. ( Nidaliidae ).

Figures

FIGURE 305 A, Uroptychus abdominalis n.sp.,paratype,ovigerous female 3.0 mm,MNHN-IU-2014-17140,Norfolk Ridge.B, U.anoploetron n.sp.,paratype,ovigerous female 2.7 mm, MNHN-IU-2014-17302,Norfolk Ridge.C, U.babai Ahyong & Poore, 2004,male 9.2 mm, MNHN-IU-2014-16300,Chesterfield Islands.D, U.elongatus n. sp., holotype,ovigerous female 4.3 mm, MNHN-IU-2014-16440,Vanuatu.E, U.joloensis Van Dam, 1933,ovigerous female, 3.0 mm,MNHN-IU-2014-16595, Vanuatu.F, U.joloensis Van Dam, 1933, ovigerous female, MNHN-IU-2014-16602,Wallis and Futuna Islands.G, U. joloensis Van Dam, 1933, male 2.3 mm and ovigerous female 2.1 mm, in situ habitat, associated with nidaliid corals, QM W25105, Papua New Guinea.H, U. nanophyes McArdle, 1901, male, 10.7 mm, MNHN-IU-2014-16757, Norfolk Ridge.I, U.nebulosus n. sp., paratype, male,8.1 mm, MNHN-IU-2014-16812,Vanuatu.