Uroptychus ciliatus ( Van Dam, 1933 )

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 : 134-136

Uroptychus ciliatus ( Van Dam, 1933)

Figure 52

Chirostylus ciliatus Van Dam, 1933: 12 , figs 17-19.

Uroptychus ciliatus — Baba 2005:33, fig. 9. — Baba et al. 2009: 42, figs 34-35. — Poore et al. 2011: 326, pl. 6, fig. F.— McCallum & Poore 2013: 160 , figs 5, 12B.

TYPE MATERIAL — Holotype: Indonesia, Kur Island , Kei Islands, 204 m, female, ( ZMA De. 101.696). [not examined].

MATERIAL EXAMINED — Indonesia, Kai Islands.KARUBAR Stn CP16, 5°17’S, 122°50’E, 315-349 m, 24.X.1991, 1 ♂ 7.0 mm (MNHN-IU-2014-16357).

– Stn CP25, 5°30’S, 132°52’E, 336-346 m, 26.X.1991, 1 ov. ♀ 7.5 mm (MNHN-IU-2014-16358) .

DISTRIBUTION„ Western Australia, Kai Islands and Taiwan; in 204- 439 m.

DIAGNOSIS — Body and appendages spinose. Carapace broader than long; greatest breadth 1.7 × distance between anterolateral spines; gastric, cardiac and branchial regions well inflated; anterolateral spine overreaching small lateral orbital spine. Rostrum narrow and elongate, with a few to several spines dorsally and marginally, breadth less than one-third carapace breadth measured at posterior carapace margin. Excavated sternum with subtriangular anterior margin, surface with sharp cristate ridge in midline on anterior half. Sternal plastron 0.7 × as long as broad, markedly broadened posteriorly; sternite 3 with shallow V-shaped anterior margin bearing pair of submedian spines; sternite 4 with 2 pairs of spines on anterolateral margin and transverse row of small spines on posterior surface, posterolateral margin slightly shorter than anterolateral margin. Anterolateral margin of sternite 5 with or without small distal spine,

distinctly shorter (0.7) than posterolateral margin of sternite 4. Abdominal somite 1 with median spine flanked by small spine; somite 2 tergite 2.5-2.9 × broader than long; pleuron anterolaterally produced, ending in blunt tip, posterolaterally strongly produced and tapering to sharp point; pleuron of somite 3 also tapering; somite 2 with anterior and posterior transverse rows each of 4 spines; somite 3 with 4 anterior and 2 posterior spines, somites 4-5 with 2 anterior and 4 posterior spines; somite 6 more spinose, posterior margin with spines. Protopod of uropod smooth on mesial margin; endopod 1.8-2.0 × longer than broad. Telson 0.6 × as long as broad, posterior plate 1.6 × longer than anterior plate, posterior margin subsemicircular (male) or slightly concave (female). Antennal article 2 with strong distolateral spine; antennal scale slightly falling short of distal end of article 5, with or without a few lateral spines; article 3 with small distolateral spine; article 5 somewhat longer than article 4, with small distolateral (dorsal) and strong distomesial (ventral) spine; article 4 also with strong distomesial spine; flagellum of 16-21 segments falling short of distal end of P1 merus. Mxp1 with bases broadly separated. Mxp3 basis with obsolescent denticles on mesial ridge; ischium with 15- 17 small denticles on crista dentata; pronounced distolateral spine on each of ischium, merus and carpus; merus 1.7-1.8 × longer than ischium. Pereopods spinose. P1 merus 1.5-1.6 × carapace length; palm as long as or slightly shorter than carpus, about 5 × longer than broad; movable finger 0.4 × length of palm. P2-3 meri subequal in length and breadth or P3 merus very slightly shorter than P2 merus, P4 merus four-fifths to three-quarters as long as and slightly narrower than P3 merus; P2 merus 1.4 × longer than carapace, 1.4-1.5 × length of P2 propodus; P4 merus 1.1-1.2 × length of P4 propodus; P2-3 carpi subequal, P4 carpus 0.8 × length of P3 carpus; carpus-propodus length ratio, 0.9 on P2, 0.8-0.9 on P3, 0.6-0.7 on P4; carpus-dactylus length ratio, 3.0 on P2-4; flexor margin with pair of terminal spines preceded by row of movable slender spines in close, zigzag arrangement in distal half on P2-3, in distal third on P4, and additional similar spines more remote from one another on remaining proximal portion; dactyli subequal, 0.3 × length of carpi, flexor margin with proximally diminishing spines, ultimate subequal to or slightly larger than penultimate.

Eggs. Number of eggs carried, 20 (excluding exuviae on right pleopods); size, 1.10 mm × 1.10 mm - 1.10 mm × 1.17 mm.

Color. A female from Taiwan was illustrated by Baba et al. (2009) and Poore et al. (2011), and an ovigerous female from Western Australia by McCallum & Poore (2013).

REMARKS — The species resembles U. spinirostris ( Ahyong & Poore, 2004) in the spinose body and appendages. In addition to the differences between the two species noted by Baba (2005), U. ciliatus is distinguished from that species by the following: the bases of Mxp1 are broadly separated rather than close to each other; and the ultimate of the flexor marginal spines of P2-4 dactyli is subequal to or slightly larger instead of smaller than the penultimate.

Uroptychus ciliatus is also close to U. quartanus n. sp. described in this paper. Their relationships are discussed under the account of that new species (see below).

Figures

FIGURE 52 Uroptychus ciliatus (Van Dam,1933), male 7.0 mm (MNHN-IU-2014-16357).A, sternal plastron,with excavated sternum and basal parts of Mxp1. B, left P2, setae omitted, lateral.C, same,distal part, setae omitted,lateral.Scale bars:1 mm.