Galathea ciliosa, Macpherson, Enrique & Robainas-Barcia, Aymee, 2015

Macpherson, Enrique & Robainas-Barcia, Aymee, 2015, Species of the genus Galathea Fabricius, 1793 (Crustacea, Decapoda, Galatheidae) from the Indian and Pacific Oceans, with descriptions of 92 new species, Zootaxa 3913 (1), pp. 1-335 : 81-83

Galathea ciliosa n. sp.

( Fig. 24 )

Material examined. Holotype: Vanuatu. SANTO, Stn AT116, 15°32.9'S, 167°16.2'E, 153–196 m, 18 October 2006: 1 M 5.4 mm (MNHN-IU-2013-15939).

Etymology. From the Latin cilium, ciliate, in reference to the numerous short setae on the carapace.

Description. Carapace: As long as broad; transverse ridges with dense short setae, without long setae; cervical groove distinct, laterally bifurcated. Gastric region with 7 transverse ridges: 1 epigastric ridge with 2 pair of spines, medially interrupted; some scales between epigastric and protogastric ridges; 2 protogastric ridges, anterior ridge medially interrupted, not extending laterally to anteriormost of branchial marginal spines, without parahepatic spines, posterior ridge uninterrupted; 2 mesogastric ridges, anterior ridge uninterrupted, not extending laterally to anterior branchial ridges, posterior ridge interrupted; 2 metagastric ridges, posterior ridge scale-like. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove. Posterior branchial region with 6 ridges, 4 of them uninterrupted. Lateral margins slightly convex medially, with 10–12 spines: 3 spines in front of and 7–9 spines behind anterior cervical groove; first anterolateral, welldeveloped, mesial to lateral margin, at level of lateral limit of orbit, second and third spines small, 2 spines ventral to between first and anterior branch of cervical groove; 3–5 spines on anterior branchial region, and 4 spines on posterior branchial margin. Small spine on limit of orbit; infraorbital margin with well-developed spine. Rostrum spatulate, 1.6 times as long as broad, length 0.5 postorbital carapace length and breadth 0.3 that of carapace; distance between distalmost lateral incisions 0.35 distance between proximalmost lateral incisions; dorsal surface with numerous setose scales; lateral margin with 5 deeply incised sharp teeth, distal pair small.

Pterygostomian flap rugose, with sparse short setae, anterior margin bluntly angular.

Sternum: About as long as broad; lateral extremities gently divergent posteriorly.

Abdomen: Somites 2–4 each with 4 uninterrupted transverse ridges on tergite, anterior ridge slightly more elevated than posterior ridges; somites 5 and 6 each with 2 uninterruted or medially interrupted ridges, posteriormedian margin of somite 6 straight. Males with G1 and G2.

Eyes: Ocular peduncles 1.3 times longer than broad, maximum corneal diameter 0.6 rostrum width.

Antennule: Article 1 with 2 well-developed subequal distodorsal and distolateral spines; distomesial spine obsolescent; lateral margin with 3 small spines. Ultimate article with tuft of fine setae on distodorsal margin.

Antenna: Article 1 with distomesial spine reaching midlength of article 2. Article 2 with 2 subequal distal spines, exceeding midlength of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with spine on flexor distal margin; crista dentata with 18 denticles. Merus slightly shorter than ischium; flexor margin with 2 subequal spines; extensor margin with 1 small distal spine. Carpus unarmed.

P1: 3.0 times carapace length, somewhat depressed on palm, more so on fingers, with numerous finely setiferous scales, with numerous long thick setae on mesial and lateral borders, some of them iridescent. Merus 1as long as carapace, twice longer than carpus, with numerous spines arranged roughly in rows, dorsomesial spines stronger; distal spines prominent. Carpus 0.7 length of palm, 1.6 times as long as broad; dorsal surface with a few small spines; mesial row of well-developed spines. Palm twice longer than broad, lateral and mesial margins with some small spines, dorsal side with a few small spines. Fingers 0.6 length of palm, each finger distally with two rows of teeth, spooned; mesial margin of movable finger and lateral margin of fixed finger unarmed.

P2–4: Moderately long, with setose striae and long plumose and non-plumose setae, some of them iridescent. P2 1.6 times carapace length. Meri successively shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus 0.7 carapace length, 4.2 times as long as broad, 2.2 times longer than P2 propodus; P3 merus 3.8 times longer than broad, 1.9 times longer than P3 propodus; P4 merus 3.1 times as long as broad, 1.3 length of P4 propodus. Extensor margins of meri with row of 10–14 proximally diminishing spines on P2–3, 2 distal spines on P4; flexor margins with 9 spines on P2, 6 on P3, and 2 on P4, distoflexor angle with 2 spines; lateral sides with some spines on P3–4. Carpi with 3–5 spines on extensor margin on P2–3, unarmed on P4; lateral surface with 2–3 small spines or acute granules sub-paralleling extensor margin on P2–4; flexor distal margin acute. Propodi 3.2–4.2 times as long as broad; extensor margin unarmed; flexor margin with 7 slender movable spines on P2–4. Dactyli distally ending in well-curved strong spine, length 0.4–0.5 that of propodi; flexor margin with 5 proximally diminishing teeth, terminal one prominent.

Epipods on P1.

Remarks. The new species belongs to the group of species with five lateral spines on the rostrum, epipods on P1 only, two or more epigastric spines and the distoflexor angle of the P2-4 meri with with spines. The closest species is G. multicristata n. sp. from New Caledonia (see under Remarks of G. multicristata ).

Distribution. Vanuatu, 153– 196 m.

Figures

FIGURE 24. Galathea ciliosa n. sp., holotype, male, 5.4 mm, Vanuatu (MNHN-IU- 2013 - 15939). A, carapace and abdomen, dorsal view; B, sternal plastron; C, left part of cephalothorax, ventral view, showing antennular and antennal peduncles, and anterior part of pterygostomian flap; D, ischium, merus and carpus of right Mxp 3, lateral view; E, left P 1, dorsal view; F, right P 2, lateral view; G, right P 3, lateral view; H, right P 4, lateral view. Scale: A, F – H = 1 mm; E = 2 mm; B – D = 0.5 mm.