Euclosia vella, Galil, 2007

Galil, Bella S., 2007, The deep-water Calappidae, Matutidae and Leucosiidae of the Solomon Islands, with a description of a new species of Euclosia Galil, 2003 (Crustacea, Decapoda, Brachyura), Zoosystema 29 (3), pp. 555-563 : 557-559

Euclosia vella n. sp.

( Figs 1 ; 2 )

TYPE MATERIAL. — Holotype: SALOMON 2, stn CP 2262, 7°56.4’S, 156°51.2’E, Vella Gulf, 460-487 m, XI.2004, ♂ cl 20.1 mm (MNHN B.30223); paratypes: same data as holotype, 1 ovigerous ♀ cl 22.1 mm, 2 juvs (MNHN B.30224).

ETYMOLOGY. — Named after the type locality, used as noun.

DISTRIBUTION. — Known only from the type locality, Solomon Islands.

DESCRIPTION

Carapace subpentagonal, globose; regions of carapace indistinct. Dorsal surface of carapace glabrous, shiny, smooth, delicately and sparsely punctate. Frontal region produced, upcurved, laterally concave.Frontal margin medially dentate, deflexed. Antennular fossa sealed by basal antennular segment. Antennae short, inserted between antennular fossa and orbit. Orbit small, rounded, outer orbital margin unsutured, anterior margin of efferent branchial channel forms part of lower orbital margin. Eyes retractable. External maxillipeds concealing trapezoid buccal opening; endopod merus triangulate, as long as ischium; in female, endopod with setose fringe lengthwise. Anterolateral margin of carapace weakly convex along hepatic region, beaded. Lateral angle of carapace rounded, overhanging thoracic sinus, margin prominently beaded. Thoracic sternites smooth. Margin of thoracic loop visible in dorsal view. Pterygostomian region smooth, with deep crescentic indentation posteriorly. Loop-shaped anterior margin of thoracic sinus with coalescent granules; row of perliform granules above cheliped basis, median granules largest. Posterolateral margins of carapace rounded, granulate, granules smaller, further apart posteriorly. Epimeral margin closely beaded, invisible in dorsal view, continuous with posterior margin. Posterior margin sinuous in male, rounded in female. Chelipeds subequal, robust, long, longer in adult male than in female specimens. Cheliped merus tubular, bearing prominent perliform tubercles on anterior, posterior margins, upper surface bearing coalesced cluster of 6-8 granules proximally, followed by two diverging rows of tubercles, distally smooth; lower surface coarsely tuberculate anteriorly, pitted proximally. Carpus inflated, bearing row of granules on inner margin. Propodus rounded, smooth, but for two rows of granules on lower surface, continuing to proximal part of pollex. Fingers as long as propodus, inner margins serrate. Pereiopods slender, short.

Pereiopodal meri bearing lines of obsolescent granules on dorsal and ventral surfaces; last pereiopodal propodus keeled dorsally, ventrally. Dactyli longer than propodi, lanceolate. Male abdominal sulcus deep, elongate, nearly reaching buccal cavity; its lateral margin bearing distinct ridge fitting into suture between abdominal segments. Male abdomen with 1st segment narrow, 2nd segment spindle-shaped, minute; segments 3-5 fused, vertically furrowed proximally; 6th segment bearing denticle medially; telson triangular, a third as long as 6th segment. Female abdomen with first 2 segments narrow, arched; segments 3-6 fused, greatly enlarged, shieldlike, telson laciniate. First male pleopod elongate, shaft stout, sinuous, tightly coiled three times on

B

itself, bearing ruff of setae preapically, apical process cornute, digitate, slender, acuminate. Second male pleopod short, curved, apex scoop-like.

Colour (in alcohol)

Dorsum dull brown, paler posteriorly, ventrally carapace ivory-coloured. Perliform tubercles on upper surface of cheliped merus pale, ringed with orange, tubercles on lower surface ivory coloured; fingers proximally pale orange, distally white. Pereiopodal meri subdistally orange; carpi, propodi, dactyli ringed with orange proximally.

REMARKS

Euclosia vella n. sp. shares with Euclosia exquisita ( Galil 2003b) , E. tornatilia ( Galil 2003b) , and E. unidentata (de Haan, 1841) , a unidentate frontal margin and a crescentic indentation on the pterygostomian region anterior to thoracic sinus. The new species is readily distinguished from the Madagascan E. exquisita in its delicately and sparsely punctuate dorsal surface of carapace, and digitate, rather than hook-like, apical process of male 1st pleopod. Euclosia vella n. sp. shares with the Australian E. tornatilia , and the East Asian E. unidentata , a slender apical process of male 1st pleopod, but it is of a much smaller size, and lacks the three and two pairs of reddish ocelli, respectively, decorating the gastric region of the latter species.

The present finding constitutes a record depth for any Euclosia species ( Galil 2003b).

Figures

FIG. 1. — Euclosia vella n. sp., holotype ♂ cl 20.1 mm, Solomon Is., Vella Gulf, SALOMON 2, stn CP 2262: A, dorsal view of carapace; B, ventral view of carapace.

FIG. 2. — Euclosia vella n. sp., holotype ♂ cl 20.1 mm, Solomon Is., Vella Gulf, SALOMON 2, stn CP 2262: A, first male pleopod; B, distal end of first male pleopod.