Galathea cephyra, 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 : 77-79

Galathea cephyra n. sp.

( Fig. 22 )

Material examined. Holotype: New Caledonia. BIOCAL. Stn DW104, 21°30.62'S, 166°21.26'E, 375–450 m, 8 September 1985: 1 M 3.1 mm (MNHN-IU-2013-13316).

Etymology. In the Greek mythology Cephyra was a daughter of Oceanus.

Description. Carapace: As long as broad; transverse ridges with dense very short setae, with scattered long setae; cervical groove distinct, laterally bifurcated. Gastric region with 5 transverse ridges: 1 epigastric ridge medially interrupted, with 2 spines; 2 mesogastric ridges, anterior one uninterrupted, not extending laterally to anteriormost branchial spines, posterior ridge scale-like; 2 metagastric ridges, anterior one medially interrupted, posterior ridge short. One hepatic and 1 parahepatic spine on each side. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 4 ridges, 2 of them uninterrupted. Lateral margins slightly convex, with 7 spines: 2 spines in front of, and 5 spines behind, anterior cervical groove; first anterolateral, well-developed, at same level of lateral limit of orbit, second small, with spine ventral to between first and second spines; 2 spines on anterior branchial region, and 3 spines on posterior branchial margin, last small. Well-developed spine on lateral limit of orbit, and 1 small frontal spine; infraorbital margin with strong spine. Rostrum 1.2 as long as broad, length 0.5 carapace length and breadth 0.4 that of carapace; distance between distalmost lateral incisions 0.25 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with some short setae; lateral margin with 4 deeply incised sharp teeth.

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

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

Abdomen: Somites 2–3 with 2 transverse uninterrupted ridges; somites 4–6 smooth; posteromedian 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 3 well-developed distal spines, distodorsal larger, distomesial spine slightly smaller. Ultimate article with a few short fine setae not in tuft on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine reaching distal margin of article 2. Article 2 with distomesial spine slightly longer than distolateral spine, reaching midlength of article 3. Article 3 with distomesial spine. Article 4 unarmed.

Mxp3: Ischium with small spine on flexor and extensor distal margins; crista dentata with 21 or 22 denticles. Merus as long as ischium; flexor margin with 2 subequal well-developed spines; extensor margin with distinct spine. Carpus unarmed.

P1: 2.9 times carapace length, somewhat depressed on palm, more so on fingers, covered with finely setiferous scales, with scattered long setae. Merus 0.9 times length of carapace, 1.3 times as long as carpus, with spines arranged roughly in rows, dorsomesial spines stronger; distal spines prominent. Carpus 0.8 length of palm, 1.8 times as long as broad; dorsal and lateral surfaces with some spines; mesial margin with some spines. Palm 1.8 times longer than broad, lateral and mesial margins slightly divergent; spines arranged roughly in dorsolateral and dorsomesial rows; dorsolateral row; 1 or 2 small spines on dorsal side. Fingers 0.9 length of palm, distally spooned, gapping, prehensile distal edges close fitting with small blunt teeth; movable finger with 1 proximal spine, movable finger missing.

P2–4: moderately slender, with setose striae and sparse long setae. P2 1.7 times carapace length; P3 longer than P2, 1.9 times carapace length; P4 shorter than P2. P2 merus 0.7 carapace length, 3.1 times as long as broad, 1.4 times longer than P2 propodus; P3 merus 3.2 times as long as broad, 1.3 times longer than P3 propodus; P4 merus 2.9 times as long as broad, 1.1 times longer than P2 propodus. Extensor margin of P2–3 meri with row of 9 proximally diminishing spines, 6 spines on P4; ventral margins distally ending in strong spine followed proximally by 0–1 spines and several eminences; lateral sides unarmed. Carpi with 5 or 6 spines on extensor margin on P2–3, 1 distal spine on P4; lateral surface with 2 or 3 spines sub-paralleling extensor margin; flexor distal margin acute. Propodi 3.5 (P2), 4.2 (P3–4) times as long as broad; extensor margin with 5–7 proximal spines on P2–4; flexor margin with 4 slender movable spines. Dactyli distally ending in well-curved strong spine, length 0.5–0.6 that of propodi; flexor margin with 4 proximally diminishing teeth, terminal one prominent.

Epipods present on P1.

Remarks. Galathea cephyra n. sp. is easily differentiated from the other closely related species (G. a l g a e Baba, 1969 from Japan and G. eulimene n. sp. from the Western Indian Ocean) by the armature of P1 (chelipeds). The P1 palm is unarmed on the dorsal surface in G. cephyra (or rarely with 1 or 2 minute spines), yet has a row of small dorsal spines in the other two species. Furthermore, G. cephyra is a deep-water species, whereas the other species live in shallow-water.

Galathea cephyra is also close to G. spinosorostris Dana, 1852 (see under Remarks of this species).

No genetic data are available for G. cephyra .

Distribution. New Caledonia, 375– 450 m.

Figures

FIGURE 22. Galathea cephyra n. sp., holotype, male, 3.1 mm, New Caledonia (MNHN-IU- 2013 - 13316). 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, right P 1, dorsal view; F, right P 2, lateral view; G, right P 3, lateral view; H, right P 4, lateral view. Scale: A, E – H = 1 mm; B – D = 0.5 mm.