Galathea eucrante, 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 : 109-111

Galathea eucrante n. sp.

( Fig. 35 )

Material examined. Holotype: Papua New Guinea. Alotau, 13 m: M 2.8 mm (UF2388).

Etymology. The name Eucrante , success, refers to one of the Nereids of Greek mythology. The name is considered as a substantive in apposition.

Description. Carapace: As long as broad; transverse ridges with dense short setae, without long plumose setae; cervical groove distinct, laterally bifurcated. Gastric region with 6 transverse ridges: 1 epigastric ridge medially uninterrupted, with 2 median spines; 2 protogastric ridges, anterior ridge uninterrupted and medially convex, 1 parahepatic spine on left side only, posterior ridge median, short and convex, with a few long and thick setae; 1 mesogastric ridge uninterrupted, not extending laterally to anteriormost of branchial marginal spines; 2 metagastric ridges, anterior one uninterrupted, extending to anterior branchial ridges, posterior ridge short. Hepatic region with 1 spine on each side. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove. Posterior branchial region with 5 transverse ridges, 3 ridges uninterrupted. Lateral margins well convex medially, with 7 spines: 2 spines in front of, and 5 spines behind, anterior cervical groove; first anterolateral, well-developed, at level of lateral limit of orbit; second, small, at midlength between anterolateral spine and anteriormost spine of branchial margin, with minute accompanying spine ventral to between first and second; 2 spines on anterior branchial region, last small, and 3 spines on posterior branchial margin, last small. Small spine on lateral limit of orbit; infraorbital margin with strong spine. Rostrum twice as long as broad, length 0.6 postorbital carapace length and breadth 0.3 that of carapace; distance between distalmost lateral incisions 0.25 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with numerous setae; lateral margin with 4 deeply incised sharp teeth.

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

Sternum: As long as broad, lateral extremities gently divergent posteriorly.

Abdomen: Somites 2–5 each with 3 or 4 transverse ridges on tergite, 2 uninterrupted; somite 6 with 2 interrupted ridges. Males with G1 and G2.

Eyes: Ocular peduncles 1.5 times longer than broad, maximum corneal diameter 0.7 rostrum width.

Antennule: Article 1 with 2 spines; well-developed distodorsal and distolateral spines, distodorsal larger; distomesial spine obsolescent. Ultimate article with tuft of long setae on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine reaching distal margin of article 2. Article 2 with 2 welldeveloped distal spines, lateral spine longer than mesial and reaching midlength of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with well-developed spine on flexor distal margin; extensor margin ending in acute angle; crista dentata with 22 denticles. Merus shorter than ischium; flexor margin with 3 spines, decreasing in size distally; extensor margin with distal spine. Carpus unarmed.

P1: 3.1 times carapace length, covered with finely setiferous scales, with numerous long setae. Merus 1.3 times length of carapace, 2.1 times as long as carpus, with spines arranged roughly in rows, dorsomesial spines stronger; distal spines prominent. Carpus 0.8 length of palm, twice longer than broad; dorsal surface with some small spines; mesial margin with 4 spines. Palm 1.8 times longer than broad, lateral and mesial margins subparallel; a few small spines arranged roughly in dorsolateral and dorsomesial rows, some small spines scattered on dorsal side. Fingers 0.8 times palm length, each finger distally with two rows of teeth, spooned; fingers each with some small proximal spines.

P2 and 4 (P3 missing): moderately slender, with setose striae and numerous long plumose setae. P2 1.8 times carapace length. Meri successively shorter posteriorly; P2 merus 0.7 carapace length, 4.4 times as long as broad, 1.5 times longer than P2 propodus; P4 merus 3.0 times as long as broad, as long as P4 propodus. Extensor margin of P2 merus with row of 10 proximally diminishing spines, and 1 spine on P4; ventral margins distally ending in strong spine followed proximally by several tubercles or eminences; lateral sides unarmed. Carpi with 4 spines on extensor margin on P2, 1 distal spine on P4; lateral surface with 3-4 acute granules sub-paralleling extensor margin; flexor distal margin ending in acute angle. P2 and P4 propodi 4.7 times as long as broad; extensor margin with 2 or 3 proximal spines; flexor margin with 5 or 6 slender movable spines. Dactyli distally ending in wellcurved strong spine, length 0.6–0.7 that of propodi; flexor margin with 5 or 6 proximally diminishing teeth, terminal one prominent.

Epipods absent on pereiopods.

Remarks. The new species is referred to the group of species characterized by the presence of one small spine on the carapace lateral margin with one small but distinct spine between the anterolateral spine and the anteriormost branchial marginal spine, two well-developed distal spines on the antennular basal article, and the possession of two epigastric spines. It resembles G. h i s p i d a Baba, 2005 from Indonesia, Kei Islands, G. barbata n. sp. from New Caledonia and Chesterfield Islands and G. punctata n. sp. from Philippines, Indonesia (Makassar Strait), Solomon Islands, Vanuatu, and New Caledonia. However, G. eucrante is easily distinguised from the others by the presence of epipods on P1–3, in contrast the other species having epipod only on P1.

No genetic data for this species are available.

Distribution. Papua New Guinea; 13 m, in sponges.

Figures

FIGURE 35. Galathea eucrante n. sp., holotype, male, 2.8 mm, Papua New Guinea (UF 2388). A, carapace and abdomen, dorsal view; B, thoracic sternites 3 and 4; 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, left P 2, lateral view; G, left P 4, lateral view. Scale: A, E, F, G = 1 mm; B – D = 0.5 mm.