Uroptychus vandamae Baba, 1988

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 : 543-546

Uroptychus vandamae Baba, 1988

Figure 275

Uroptychus vandamae Baba, 1988: 49 (part), fig. 21. — McCallum & Poore 2013: 169 , fig. 12H.

Uroptychus australis var. indicus — Van Dam 1933:18 (part), figs 25, 27, 28.

Not Uroptychus vandamae — Baba 1990: 942, fig. 8c (= 2 new species, see below under the remarks).

TYPE MATERIAL — Holotype: Indonesia, Molucca Sea off west coast of Halmahera, 655 m, male ( USNM 150316 ) (Not

ov. female from Albatross Stn 5664 in Makassar Strait = U. australis ( Henderson, 1885)) . [not examined].

MATERIAL EXAMINED — Indonesia, Kai Islands. KARUBAR Stn CP19, 5°15’S, 133°01’E, 605- 576 m, 25.X.1991, 1 ♂ 5.9 mm, 1 ov. ♀ 6.8 mm, 2 ♀ 4.5, 5.9 mm, 1 sp. (sex indet.) 3.1 mm (MNHN-IU-2014-17009). – Stn CP20, 5°15’S, 132°59’E, 769-809 m, with Chrysogorgia sp. ( Calcaxonia , Chrysogorgiidae ), 25.X.1991, 17 ♂ 6.0- 7.8 mm, 14 ov. ♀ 5.8-7.1 mm, 10 ♀ 4.0- 7.6 mm (MNHN-IU-2014-17010) . – Stn CC 21, 5°14’S, 133°00’E, 688-694 m, 25.X.1991, 1 ♂ 7.2 mm, 1 ♀ 6.4 mm (MNHN-IU-2014-17011); 4 ♂ 7.1-7.6 mm, 4 ov. ♀ 6.1-6.6 mm, 1 ♀ 6.4 mm (MNHN-IU-2014-17012). Indonesia, Makassar Strait. CORINDON Stn CH 201, 01°11’S, 117°06’E, 21 m, 1 ♂ 6.3 mm (MNHN-IU-2014-17013). Solomon Islands. SALOMON 2 Stn CP 2230, 6°27.8’S, 156°24.3’E, 837-945 m, 29.X.2004, 3 ♂ 4.5-6.7 mm, 3 ov. ♀ 5.3-6.4 mm, 1 ♀ 5.9 mm (MNHN-IU-2014-17014) .

DISTRIBUTION„ Molucca Sea off west coast of Halmahera, Timor Sea, off Roti, Makassar Strait and Western Australia, in 463-1289 m, and now Makassar Strait, Kai Islands and Solomon Islands, in 605- 945 m. The male from the Makassar Strait (MNHN-IU-2014-17013) was taken in 21 m, but this depth record is questioned.

SIZE„ Males, 4.5-7.8 mm; females, 4.0- 7.6 mm; ovigerous females from 5.3 mm.

DIAGNOSIS„ Medium-sized species. Carapace: 1.1-1.2 × longer than broad; greatest breadth 1.6 × distance between anterolateral spines. Dorsal surface smooth and glabrous, unarmed; lateral margins convexly moderately divergent posteriorly; anterolateral spine slightly overreaching lateral orbital spine. Rostrum narrow, elongate triangular, with interior angle of about 20°, dorsally somewhat convex from side to side, extending far beyond cornea, length more than half that of carapace, breadth half carapace breadth at posterior carapace margin. Lateral orbital spine small, often obsolete but acuminate, its base somewhat anterior to that of anterolateral spine. Pterygostomian flap with anterior margin somewhat roundish, bearing small spine. Excavated sternum with small sharp median process between bases of Mxp1, surface with small central spine. Sternal plastron slightly shorter than broad, lateral extremities straightly divergent posteriorly; sternite 3 well depressed, anterior margin deeply excavated, with 2 submedian spines separated by semicircular or narrow notch; sternite 4 having anterolateral margin anteriorly ending in well-developed process followed by posteriorly diminishing crenulations, posterolateral margin slightly more than half-length of anterolateral margin; anterolateral margin of sternite 5 convexly slightly divergent posteriorly, about as long as posterolateral margin of sternite 4. Abdominal somite 1 weakly ridged transversely; somite 2 tergite 2.4-2.6 × broa- der than long; pleuron posterolaterally blunt, lateral margin weakly concave and moderately divergent posteriorly; pleuron of somite 3 posterolaterally blunt. Telson half as long as broad or slightly more than so; posterior plate 1.7- 1.8 × longer than anterior plate, posterior margin emarginate. Eyes usually terminating in midlength of rostrum, relatively broad (1.6 × longer than broad), slightly narrowed proximally, lateral margins convex; cornea slightly longer than remaining eyestalk. Ultimate article of antennular peduncle twice as long as high. Antennal peduncle slightly overreaching cornea; article 2 with acute lateral spine; antennal scale slender, terminating in midlength of article 5; distal 2 articles unarmed; article 5 slightly more than twice as long as article 4, breadth less than half height of ultimate article of antennule; flagellum consisting of 13-15 segments, falling short of distal end of P1 merus. Mxp1 with bases close to each other. Mxp3 basis with 4 denticles on mesial ridge; ischium with flexor margin not rounded distally, crista dentata with 13-15 denticles; merus 2.2-2.5 × longer than ischium, distolateral spine obsolescent, flexor margin roundly ridged on proximal two-thirds. P1 slender, unarmed except for ischium, setose on fingers; ischium with small or obsolescent dorsal spine, ventromesially without subterminal spine; merus 1.1-1.2 × length of carapace; carpus 1.2 × length of merus; palm 0.8-0.9 × length of carpus; fingers proportionately broad, distally ending in tiny incurved spine, not distinctly crossing distally when closed, gaping in large males; movable finger with subtrapezoid proximal process (in dorsal view) in large males, low process in females and small males. P2-4 well compressed mesio-laterally, unarmed on meri and carpi, with long setae especially numerous on propodi; meri successively shorter posteriorly (P3 merus 0.9-1.0 × length of P2 merus, P4 merus 0.6-0.7 × length of P3 merus), subequally broad on P2 and P3, much narrower on P4 (P4 merus 0.8 × breadth of P3 merus); P2 merus 0.8-0.9 × length of carapace, 1.2 × length of P2 propodus, P4 merus 0.8-0.9 × length of P4 propodus; P2 carpus subequal to or slightly longer than P3 carpus, P4 carpus shortest; carpus-propodus length ratio, 0.6 on P2, 0.5-0.6 on P3 and P4; carpus-dactylus length ratio, 1.3-1.5 on P2, 1.2-1.5 on P3, 1.0 on P4; propodi slightly shorter on P2 than on P3 or subequal on P2 and P3, shortest on P4; flexor margin somewhat convex medially, with 5-6 spines on distal half, terminal (ultimate) spine single, somewhat distant from juncture with dactylus, penultimate spine remotely separated from ultimate; dactyli curving at proximal quarter, dactylus-carpus length ratio, 0.6-0.8 on P2, 0.7-0.9 on P3, 1.0 on P4; dactylus-propodus length ratio, 0.4 on P2 and P3, 0.4-0.5 on P4; flexor margin with 2 groups of spines remotely separated; distal group of 2 larger spines, terminal longer; proximal group of 6-8 smaller spines, all oriented parallel to flexor margin.

Eggs. Number of eggs carried, 6-25; size, 1.15 mm × 1.18 mm - 1.46 mm × 1.58 mm.

Color. Illustrated by McCallum & Poore (2013) for a western Australian specimen.

REMARKS„ Reexamination of the type material of U. vandamae disclosed that the female paratype from Albatross Station 5664 is different from both the holotype and the male paratype from Albatross Station 5620 in having a small anterolateral spine situated distinctly posterior to the lateral orbital spine, in having the antennal scale reaching the distal end of antennal article 5, and in having the terminal of the flexor spines of P2-4 propodi paired, not single. This specimen is referred to U. australis ( Henderson, 1885) (see above under U. australis ).

The material reported under U. vandamae by Baba (1990) from Madagascar contains two species, both different from U. vandamae : one includes all of the specimens from Vauban Station 102 and the other includes the remaining material taken at 13 other stations. The former is characterized by having a pair of epigastric spines that are variable from distinct to obsolete, the antennal scale terminates in the midlength of the antennal article 5, the P2-4 propodi bear a pair of terminal spines preceded by nearly equidistantly arranged single spines on the flexor margin, and the P2-4 dactyli bear flexor spines arranged regularly, not separated into proximal and distal groups. The latter is much like U. vandamae but differs in having a pair of distinct epigastric spines, in having the antennal scale overreaching the antennal article 5, and in having the P2-4 dactyli bearing a distal group of three spines, not two spines as in U. vandamae . These two species are apparently new to science and will be described later elsewhere. The male from Valdivia Station 245 in Zanzibar Canal (SMF 4549) reported under U. vandamae by Baba (1990) is referable to the first of the above species.

As mentioned by Baba (1988), four lots of the SIBOGA material reported under U. australis var. indicus by Van Dam (1933) are referable to U. vandamae . The remaining two lots, one from SIBOGA Station 262 and the other from Station 266, both from the Kai Islands, are different from U. vandamae in having a longer antennal scale reaching the distal end of article 5, and in having flexor spines of the P2-4 dactyli arranged regularly, with no remote separation into proximal

and distal groups. These materials have the ultimate of the flexor spines of P2-4 dactyli stronger than the penultimate, the feature not in agreement with that of U. indicus Alcock, 1901 ( Figure 217 ). Reexamination of these specimens is recommended to establish their systematic status.

The combination of the following characters may characterize U. vandamae : the P2-4 dactyli bear distal and proximal groups of flexor marginal spines that are remotely separated from each other; and the ultimate of the flexor marginal spines of the P2-4 propodi is moderately remote from the juncture with dactyli and the penultimate spine is remarkably distant from the ultimate.

Figures

FIGURE 217 Uroptychus indicus Alcock,1901,syntype,ovigerous female 7.2 mm (ZSI 9328/9).A, carapace,dorsal.B, anterior part of sternal plastron.C, telson. D, left antenna,ventral.E, left Mxp3, setae omitted,lateral.F, right P1, distal part,dorsal.G, left P2,dactylus and propodus,setae omitted,lateral. H, same,distal part,lateral.Scale bars:1 mm.

FIGURE 275 Uroptychus vandamae Baba,1988,ovigerous female 6.9 mm (MNHN-IU-2014-17010). A, carapace and anterior part of abdomen, lateral. B, anterior part of carapace, dorsal. C, sternal plastron, with excavated sternum and basal parts of Mxp1. D, right Mxp3, setae omitted, ventral. E, left P2, distal articles, setae omitted, lateral.F, same. G, right P4, distal articles, setae omitted, lateral. H, same. Scale bars: 1 mm.