Galathea tribulosa, 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 : 313-314

Galathea tribulosa n. sp.

( Figs 51 D–F, 111)

Material examined. Holotype: Solomon Islands. SALOMON 2, Stn CP2287, 08°39.84'S, 157°23.505'E, 253–255 m, 6 November 2004: 1 ov. F 4.2 mm (MNHN-IU-2013-15857).

Paratypes: Solomon Islands. SALOMON 1, Stn CP1860, 09°22'S, 160°31'E, 620 m, 7 October 2001: 1 M 3.8 mm (MNHN-IU-2013-15859). SALOMON 2, Stn CP2210, 07°33.5'S, 157°42.3'E, 240–305 m, 26 October 2004: 1 ov. F 5.8 mm (MNHN-IU-2013-15858).—Stn CP2287, 08°39.84'S, 157°23.505'E, 253–255 m, 6 November 2004: 1 ov. F 6.2 mm (MNHN-IU-2013-15860).

Etymology. From the Latin tribulosus, thorny, in reference to the acute and thin rostrum.

Description. Carapace: 1.2 times longer than broad; transverse ridges with dense short setae, without long setae; cervical groove distinct, laterally bifurcated. Gastric region with some transverse ridges: 1 epigastric ridge, scale-like, with 6 small spines; 2 protogastric ridges, anterior ridge uninterrupted, medially convex, with 2 parahepatic spines on each side, posterior scale-like; 2 mesogastric ridges, anterior ridge uninterrupted and not extending laterally to anteriormost of branchial marginal spines, posterior ridge scale-like; 2 metagastric ridges, anterior ridge uninterrupted, not continuing laterally to anteriorbranchial ridge, posterior ridge short. Hepatic region with 1 or 2 small spines. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove. Posterior branchial region with 6 transverse ridges, 2 ridges uninterrupted. Lateral margins subparallel, with 7 spines: 2 spines in front of, and 5 spines behind, anterior cervical groove; first anterolateral, well-developed, slightly behind level of lateral limit of orbit, 1 small spine at midlength between anterolateral spine and anterior cervical groove, with small spine ventral to between first and second; 3 spines on anterior branchial region, and 2 spines on posterior branchial margin. Small spine on lateral limit of orbit, 1 small frontal spine between orbit and first anterolateral spine; infraorbital margin with some small spines. Rostrum narrow, 2.5 times 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 horizontal, with numerous small scale-like setose ridges; lateral margin with 4 shallowly incised teeth, distal pair minute and clearly smaller than previous pair.

Pterygostomian flap rugose, unarmed, ridges with short setae, anterior margin acute; upper margin, near linea anomurica, with numerous small teeth.

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

Abdomen: Somites 2–4 each with 2 or 3 uninterrupted and 1 or 2 interrupted ridges; somite 5 with 2 uninterrupted ridges, somite 6 with 2 medially interrupted ridges. Males with G1 and G2.

Eyes: Ocular peduncles 1.5 times longer than broad, maximum corneal diameter 0.9 rostrum width.

Antennule: Article 1 with 2 well-developed distal spines, distodorsal larger, distomesial obsolescent; 3 small spines along lateral margin. Ultimate article with a few long fine setae in tuft on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine not reaching end of article 2. Article 2 with 2 distal spines, distolateral spine longer than distomesial, and barely reaching end of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with flexor margins ending in small spine, extensor margin ending in acute angle; crista dentata with 20 or 21 denticles. Merus as long as ischium; flexor margin with 3 spines, proximal spine clearly longer than others, median spine smaller than distal; extensor margin ending in small spine. Carpus unarmed.

P1: 3.8 times carapace length, with numerous setiferous small scales, and some scattered long setae. Merus 1.6 times carapace length, 2.0 times as long as carpus, with numerous spines, dorsomesial and distal spines stronger than others. Carpus 0.7 length of palm, 4.0 times as long as broad; dorsal surface with some small spines; mesial margin with row of spines. Palm 4.4 times longer than broad, lateral and mesial margins subparallel; small spines arranged roughly in dorsal, dorsolateral and dorsomesial rows. Fingers unarmed, 0.7 times palm length, each finger distally with two rows of teeth, spooned.

P2–4: long and slender, with some setose striae and sparse long setae. P2 2.4 times carapace length. Meri successively shorter posteriorly (P3 merus 0.7 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus as long as carapace, 6.8 times as long as broad, 1.2 times longer than P2 propodus. P3 merus 5.2 times as long as broad, 1.1 times longer than P3 propodus. P4 merus 4.2 times as long as broad, 0.9 times longer than P4 propodus. Extensor margin with row of 9 proximally diminishing spines on P2–3, 6 spines on P4; ventral margins distally ending in strong spine, lateral sides with row of small spines on P2–4. Carpi with 6 or 7 spines on extensor margin on P2–4; lateral surface with 5 or 6 small spines sub-paralleling extensor margin; flexor distal margin acute. Propodi equally broad on P2–4, 7.7 (P2), 7.2 (P3), 6.7 (P4) times as long as broad; extensor margin with 1–4 small proximal spines; flexor margin with 7 or 8 slender movable spines, distal two spines with another smaller spine mesial to them. Dactyli distally ending in well-curved strong spine, length 0.5 that of propodi; flexor margin with 7 or 8 proximally diminishing teeth, distal one clearly larger than penultimate.

Epipods present on P1.

Remarks. The new species most closely resembles G. inconspicua Henderson, 1885 ; differentiang characters are discussed under Remarks of G. inconspicua .

Distribution. Solomon Islands, 240– 620 m.

Figures

FIGURE 51. Rostrum, dorsal view. Galathea inconspicua Henderson, 1885: A, Chesterfield Islands, male, 4.4 mm (MNHN- IU- 2013 - 8505); B, Vanuatu, ovigerous female, 4.8 mm (MNHN-IU- 2013 - 13949); C, Vanuatu, male, 5.5 mm (MNHN-IU- 2013 - 8504). Galathea tribulosa n. sp.: D, Solomon Islands, male, 3.8 mm (MNHN-IU- 2013 - 15859); E, Solomon Islands, ovigerous female, 5.8 mm (MNHN-IU- 2013 - 15858); F, Solomon Islands, ovigerous female, 6.2 mm (MNHN-IU- 2013 - 15860). Scale = 1 mm.