Uroptychus multispinosus Ahyong & Poore, 2004

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 : 326-329

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Uroptychus multispinosus Ahyong & Poore, 2004


Uroptychus multispinosus Ahyong & Poore, 2004

Figures 156 View FIGURE 156 , 157 View FIGURE 157

Uroptychus multispinosus Ahyong & Poore, 2004: 60 View Cited Treatment , fig. 17.

TYPE MATERIAL — Holotype: Australia, E of Southport , Queensland, 318 m, female ( AM P31415 View Materials ). [not examined].

MATERIAL EXAMINED — New Caledonia, Norfolk Ridge.CHALCAL 2 Stn DW74, 24°49.36’S, 168°38.38’E, 650 m, 29.X.1986, 1 ♂ 3.2 mm ( MNHN- IU-2014-16743) .

DISTRIBUTION„ Southern Queensland, and now New Caledonia; 318- 650 m.

DESCRIPTION„ Small species. Carapace: As long as broad; greatest breadth 1.6 × distance between anterolateral spines. Dorsal surface convex from anterior to posterior, with feeble depression between gastric and cardiac regions, bearing scattered short setae. Lateral margins posteriorly divergent but slightly convex on posterior branchial region; anterolateral spine small, barely reaching tip of lateral orbital spine, followed by 5 or 6 very small, obsolescent spines along entire margin; no ridge along posterior lateral margin. Rostrum narrow triangular, with interior angle of 15°, horizontal on ventral surface, dorsally concave, laterally with small subterminal spine on each side; length about half that of remaining carapace, breadth about half carapace breadth at posterior carapace margin. Lateral orbital spine as large as anterolateral spine, situated slightly anterior to level of, and separated from that spine by its basal breadth. Pterygostomian flap with spinules on surface, anteriorly angular, produced to small spine.

Sternum: Excavated sternum moderately convex on anterior margin, surface with distinct ridge in midline. Sternal plastron somewhat broader than long. Sternite 3 shallowly depressed; anterior margin shallowly excavated, with broad median notch flanked by very small spine, lateral end with a few very small spines. Sternite 4 anterolaterally blunt angular, anterolateral margin smooth, more than twice as long as posterolateral margin. Sternite 5 slightly broader than sternite 4, anterolateral margins anteriorly convex, subparallel, much longer than posterolateral margin of sternite 4. Sternites 6 and 7 subequal in breadth, broader than sternite 5.

Abdomen: More setose than carapace. Somite 1 moderately convex from anterior to posterior. Somite 2 tergite 2.4 × broader than long; pleuron posterolaterally blunt; lateral margin slightly concave and somewhat divergent posteriorly. Pleuron of somite 3 with blunt lateral terminus. Telson slightly less than half as long as broad; posterior plate somewhat concave on posterior margin, length 0.8 × that of anterior plate.

Eye: 1.8 × longer than broad, slightly overreaching midlength of rostrum, somewhat narrowed distally. Cornea half as long as remaining eyestalk.

Antennule and antenna: Ultimate article of antennular peduncle 2.9 × longer than high. Antennal peduncle relatively short, terminating in distal end of cornea. Article 2 with sharp lateral spine. Antennal scale overreaching peduncle by full length of article 5, breadth 1.7 × that of article 5. Distal 2 articles short relative to breadth, each with distinct distomesial spine; article 5 as long as article 4; breadth 0.7 × height of ultimate antennular article. Flagellum of 9 segments far falling short of distal end of P 1 merus.

Mxp: Mxp1 with bases broadly separated. Mxp3 basis without distinct denticles on mesial ridge. Ischium with very small denticles on crista dentata, bearing tuft of setae lateral to rounded distal end of flexor margin. Merus twice as long as ischium, flattish on mesial face; flexor margin ridged, with 2 or 3 small spines on distal third; distolateral spine short and small. Carpus also with distolateral spine.

P 1: 5.7 × longer than carapace, setose, relatively massive. Ischium with well-developed distodorsal spine; ventromesial margin with 2 or 3 small denticle-like processes on proximal portion, lacking subterminal spine. Merus with granulate scale-like ridges supporting setae on dorsal surface and tubercles on proximal mesial portion; length 1.1 × that of carapace. Carpus 1.1 × longer than merus, ventrally bearing small distolateral spine. Palm unarmed, about 3 × longer than broad, distally somewhat broader, 1.2 × longer than carpus. Fingers stout, distally crossing when closed. Movable finger falling short of distal end of fixed finger when closed, opposable margin with median process fitting to between 2 low processes on opposite fixed finger; length slightly less than half (0.45) that of palm.

P 2-4: Broad relative to length, moderately setose. Meri successively shorter posteriorly ( P 3 merus 0.9 × length of P 2 merus, P 4 merus 0.9 × length of P 3 merus), equally broad on P 2 and P 3, slightly narrower on P 4 ( P 4 merus 0.9 × as broad as P 3); length-breadth ratio, 2.8 on P 2, 2.9 on P 3, 2.5 on P 4; dorsal margin with a few small proximal spines distinct on P 2 and P 3, obsolescent on P 4. P 2 merus 0.7 × length of carapace, subequal to length of P 2 propodus; P 3 merus 0.9 × length of P 3 propodus; P 4 merus 0.8 length of P 4 propodus. Carpi successively slightly shorter posteriorly; distinctly shorter than dactyli, carpus-dactylus length ratio, 0.9 on P 2, 0.7 on P 3 and P 4; carpus-propodus length ratio, 0.4 on P 3 and P 4. Propodi subequal on P 3 and P 4, shorter on P 2 ( P 2 propodus 0.8 × length of P 3 propodus); flexor margin nearly straight, ending in pair of spines preceded by 6 spines on P 2 and P 3, 5 spines on P 4. Dactyli slender relative to propodi, length more than half (0.52 on P 2, 0.53 on P 3, 0.56 on P 4) that of propodus; dactylus-carpus length ratio, 1.2 on P 2, 1.4 on P 3, 1.5 on P 4; flexor margin nearly straight on P 2, slightly curving on P 3, more distinctly so on P 4, bearing 7 spines, ultimate spine slender and very close to penultimate, 2 proximal spines small and slender and strongly inclined, 4 other spines strong, somewhat inclined, and widely spaced.

REMARKS — The present specimen agrees with the original description of U. multispinosus , with only small differences: the dorsal margins of P 2 and P 3 meri bear small spines instead of being unarmed and the lateral marginal spines of the carapace are very small and obsolescent instead of small and distinct. These difference are here regarded as individual variations.

This species strongly resembles U. vicinus n. sp. Their relationships are discussed under the remarks of that species (see below).














Uroptychus multispinosus Ahyong & Poore, 2004

Baba, Keiji 2018

Uroptychus multispinosus

AHYONG S. T. & POORE G. C. B. 2004: 60