Uroptychus triangularis Miyake & Baba, 1967

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 : 526-527

Uroptychus triangularis Miyake & Baba, 1967

Uroptychus triangularis Miyake & Baba, 1967: 203 , fig. 1. — Baba et al. 2009: 64, figs 54, 55. — Poore et al. 2011: 331, pl. 8, fig. D.

TYPE MATERIAL — Holotype: Japan, near Muko-jima , Ogasawara Island, ov. female ( ZLKU 4883 ). [not examined].

MATERIAL EXAMINED — Philippines. MUSORSTOM1Stn CP03, 14°01’N, 120°15’E, 183-185 m, 19.III.1976 ,1ov. ♀ 3.0mm (MNHN-IU-2014-16994).

DISTRIBUTION„ Ogasawara Islands ( Japan), Taiwan and now the Philippines; in 183- 236 m.

DIAGNOSIS„ Small species. Carapace subtriangular in dorsal view, 1.5 × broader than long; greatest breadth 2.2 × distance between anterolateral spines. Dorsal surface gently convex from anterior to posterior, nearly glabrous, with very small, scattered spines on anterior half; lateral margins strongly divergent to point one-third from posterior end, then convergent, bearing row of spines: first anterolateral, directed slightly anterolaterally, distinctly overreaching lateral orbital spine; second as long as first, located at anterior end of anterior branchial region; third strongest, basally broad and subtriangular, located at anterior end of posterior branchial region, followed by 3 or 4 posteriorly diminishing, short subtriangular spines. Rostrum narrow triangular, horizontal, with interior angle of 22°, length more than half that of remaining carapace, breadth slightly more than one-third carapace breadth at posterior carapace margin; dorsal surface concave. Lateral orbital spine small, directly mesial to anterolateral spine. Pterygostomian flap anteriorly angular, produced to sharp spine, surface with small spines. Excavated sternum sharply triangular on anterior margin, surface with rounded ridge in midline. Sternal plastron 1.7 × broader than long, lateral extremities convexly divergent posteriorly; sternite 3 deeply excavated on anterior margin, with pair of small submedian spines; sternite 4 having anterolateral margin twice as long as posterolateral margin, anteriorly ending in small spine; anterolateral margin of sternite 5 2 × longer than posterolateral margin of sternite 4. Somite 1 of abdomen without transverse ridge; somite 2 tergite 3.1 × broader than long; pleural lateral margin strongly concave and strongly divergent posteriorly, posterolateral corner angular; pleuron of somite 3 with blunt terminus. Telson 0.4 × as long as broad, posterior plate slightly longer than anterior plate, somewhat emarginate on posterior margin. Eyes slightly broadened proximally, elongate, slightly more than twice as long as broad, overreaching midlength of rostrum; cornea less than half length of remaining eyestalk. Ultimate article of antennular peduncle 2.4 × longer than high. Antennal peduncle overreaching cornea; article 2 with small distolateral spine; antennal scale overreaching proximal first segment of flagellum; distal 2 articles each with well-developed distomesial spine; article 5 slightly longer than article 4, breadth slightly more than half height of antennular ultimate article; flagellum consisting of 10 segments, not reaching distal end of P1 merus. Mxp1 with bases close to each other. Mxp3 basis with 3-4 denticles on mesial ridge; ischium with about 20 denticles on crista dentata, flexor margin not rounded distally; merus 1.9 × longer than ischium, distolateral spine well developed, flexor margin with 2 or 3 small spines distal to midlength, extensor margin with very small distal spine; carpus with distolateral spine and 2 extensor marginal spines. P1 massive; ischium with strong distodorsal spine, ventromesial margin with row of tubercle-like spines, without subterminal spine; merus as long as carapace; short stout spines on merus and carpus; carpus slightly longer than merus; palm 2.2 × longer than broad, 1.5 × longer than carpus, with a few spines along proximal part of mesial margin; fingers strongly incurved distally; opposable margin of fixed finger sinuous, that of movable finger with obtuse proximal process. P2 and P4 meri equally broad (P3 missing); P2 merus 3.0 × longer than broad, shorter than carapace, subequal to or slightly shorter than P2 propodus; P4 merus 2.4 × longer than broad, 0.8 × length of P2 merus, 0.8 × length of P4 propodus; dorsal margin with 4 spines on P2, 2 spines on P4, other than very small terminal spine; carpi 1.1 × as long as dactyli on P2, 0.8 × on P4, about half as long as propodi on P2, 0.4 × as long on P4; propodi shorter on P4 than on P2, extensor margin with plumose setae on distal portion, flexor margin slightly convex, with pair of terminal spines preceded by 5 spines on P2, 4 spines on P4; dactyli 0.9 × length of carpi on P2, 1.2 × on P4, slightly less than half as long as propodi on P2 and P4, flexor margin somewhat curving, bearing 12 sharp triangular spines, ultimate spine shorter and narrower than penultimate, subequally broad as antepenultimate as well as remaining spines.

Eggs. Number of eggs carried, 9; size, 0.90 mm × 1.1 mm - 1.05 mm × 1.16 mm.

Color. A specimen from Taiwan was illustrated by Baba et al. (2009) and Poore et al. (2011).

REMARKS — The second specimen of the species was recorded from Taiwan ( Baba et al. 2009). This is the third specimen.

No additional characters of significance are noted.