Uroptychus zezuensis Kim, 1972

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 : 565-566

Uroptychus zezuensis Kim, 1972

Uroptychus zezuensis Kim, 1972: 53 , figs 1, 2. — Kim 1973:171, fig. 17, pl. 64, figs 4a, 4b. — Baba 2005: 64, fig. 23. — Baba et al. 2009:66, figs 56-58. — Poore et al. 2011: 330, pl. 8, figs F, G.

TYPE MATERIAL — Holotype: Korea, south of Seogwipo, Jeju Island , ov. female, ( SNU). [not examined].

MATERIAL EXAMINED — Philippines. MUSORSTOM 1 Stn CP03, 14°01’N, 120°15’E, 183-185 m, 19.III.1976, 1 ♂ 4.2 mm, 1 ♀ 3.2 mm ( MNHN- IU-2014-17087) . – Stn CP27, 14°00’N, 120°16’E, 192- 188 m, 22.III.1976, 1 ♂ 5.0 mm (MNHN-IU-2014-17088 [=MNHN-Ga 4614]) (incorporated in Baba 2005) . – Stn CP63, 14°00’N, 120°16’E, 191-195 m, 27.III.1976, 1 ♂ 4.9 mm, 1 ov. ♀ 5.2 mm (MNHN-IU-2014-17089 [=MNHN-Ga 4615]) (incorporated in Baba 2005) . MUSORSTOM 2 Stn CP01, 14°00’N, 120°18’E, 198- 188 m, 20.XI.1980, 1 ov. ♀ 4.7 mm (MNHN-IU-2014-17090) . – Stn CP19, 14°01’N, 120°18’E, 189-192 m, 22.XI.1980, with Chironephthya sp. ( Alcyoniina : Nidaliidae ), 1 ♀ 5.1 mm (MNHN-IU-2014-17091) . MUSORSTOM 3 Stn CP108, 14°01’N, 120°18’E, 188-195 m, with Chironephthya sp. ( Alcyoniina : Nidaliidae ), 2.VI.1985, 1 ♂ 4.5 mm, 1 ♀ 2.4 mm (MNHN-IU-2014-17092) .

DISTRIBUTION„ Nagasaki ( Japan), Jeju Island ( Korea), Taiwan, and the Philippines; 60- 311 m.

SIZE„ Males, 4.2-5.0 mm; females, 2.4-5.2 mm; ovigerous females from 3.4 mm.

DIAGNOSIS„ Small species. Carapace slightly broader than long, greatest breadth 1.5-1.6 × distance between anterolateral spines. Dorsal surface slightly convex from anterior to posterior; lateral margins convex, with 5 spines on anterior half: first anterolateral, moderate in size, overreaching smaller lateral orbital spine; second and third small; fourth and fifth acute, subequal, both much larger than first; fifth situated slightly anterior to midlength. Rostrum narrowly triangular, with interior angle 20-30°, slightly deflected ventrally, deeply concave dorsally, lateral margin with or without small subapical spine on each side, breadth slightly more than half carapace breadth at posterior carapace margin. Pterygostomian flap with spinules on surface, anteriorly angular, produced to sharp spine. Excavated sternum with distinct ridge in midline on surface, anterior margin broadly subtriangular between broadly separated bases of Mxp1. Sternite 3 shallowly depressed, anterior margin shallowly concave, with narrow or relatively broad U-shaped median notch; sternite 4 with anterolateral margin slightly convex and anteriorly angular, posterolateral margin 0.8 × as long as anterolateral margin; anterolateral margin of sternite 5 about as long as posterolateral margin of sternite 4. Abdominal somite 2 tergite 2.3 × broader than long; pleuron posterolaterally bluntly angular, lateral margins subparallel or weakly concave and weakly divergent posteriorly. Pleuron of somite 3 with bluntly angular posterolateral terminus. Telson with posterior margin feebly or more or less concave, not distinctly emarginated. Eyes 1.8 × longer than broad, slightly narrowed distally, reaching midlength of rostrum; cornea about half as long as remaining eyestalk. Antennal peduncle overreaching cornea; article 2 with acute lateral spine; antennal scale overreaching article 5 but not its distal spine; distal 2 articles each with very strong distomesial spine, article 5 about twice as long as article 4; flagellum not reaching distal end of P1 merus. Mxp3 having ischium with small spine directly lateral to rounded distal end of flexor margin, crista dentata with very small denticles; merus 1.9-2.0 × longer than ischium, with 1 distolateral spine and 1-3 small spines distal to midlength of flexor margin; carpus with 1 distolateral and 1 extensor marginal spine. Pereopods with long non-plumose setae. P1 ischium dorsally with strong spine often with accompanying smaller spine proximal to it, ventromesially with strong subterminal spine; merus and carpus usually with distomesial and distolateral spines ventrally, merus with row of 3 spines arranged obliquely on proximal part of ventromesial surface

and row of 3 spines on ventral surface, length 1.2-1.3 × that of carapace; fingers more or less tapering, gently incurved distally, about half as long as palm. P2-4 moderately broad in lateral view, with long, distally softened setae; meri successively shorter posteriorly, equally broad on P2-4; dorsal margin smooth, without spines; P2 merus slightly shorter than carapace, 1.1 × length of P2 propodus; P3 merus 0.9-1.0 × length of P3 propodus; P4 merus 0.8 × length of P4 propodus; carpi subequal; length 0.4 × that of propodi on P2-4; propodus with straight flexor margin bearing pair of terminal spines preceded by 1 spine on P2, none on P3 and P4; dactyli slightly less than half as long as propodi, about as long as carpi (dactylus-carpus length ratio, 0.9-1.0 on P2, 1.0 on P3, 1.1 on P4); flexor margin with slender ultimate spine preceded by 5 or 6 spines on flexor margin, penultimate and antepenultimate strong, triangular, subequal and perpendicular to flexor margin, remaining proximal spines diminishing toward base of article, proximal-most spine inclined.

Eggs. Number of eggs carried up to 18; size, 0.83 mm × 0.85 mm - 0.95 mm × 1.05 mm.

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

REMARKS„ The part of the series from the Philippines (MNHN-Ga 4614, 4615) was incorporated in Baba (2005), in which the relationships between U. zezuensis and U. tridentatus ( Henderson, 1885) were discussed.

This species is very similar to U. joloensis Van Dam, 1939 in morphology, coloration and host preference. Morphologically, U. zezuensis differs from U. joloensis in having the carapace lateral margin with five instead of three spines including the anterolateral spine (the last two being larger and sharper), in having the antennal scale distinctly overreaching instead of barely reaching the end of article 5, and in having the sternite 3 anterior margin more deeply excavated. The coloration was illustrated by Baba et al. (2009). It differs from that of U. joloensis (= U. kudayagi ) in having a red spot around the hepatic region rather than around the rostrum.

The alcyonacean Siphonogorgia sp. ( Nidaliidae ) is known as a host associate ( Baba et al. 2009). Two lots from the Philippines here examined (MNHN-IU-2014-17091; MNHN-IU-2014-17092) were taken with Chironephthya sp. ( Nidaliidae ). The red spots on both the carapace and P1 well harmonize with the color of the host’s polyps, just as displayed by U. joloensis (see above).