Galathea anoplos, 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 : 41-42

Galathea anoplos n. sp.

( Fig. 9 )

Material examined. Holotype: Solomon Islands. SALOMON 1, Stn DW1854, 9°46.4'S, 160°52.9'E, 229–260 m, 7 October 2001: 1 M 5.2 mm (MNHN-IU-2013-15867).

Etymology. From the Greek, anoplos , unarmed, in reference to the unarmed dorsal carapace surface.

Description. Carapace: as long as broad; transverse ridges with dense short setae, and some scattered long non-plumose iridescent setae; cervical groove shallow, but distinct, laterally bifurcated. Dorsal surface unarmed. Gastric region with 5 transverse ridges: 1 epigastric ridge, uninterrupted; 2 protogastric ridges, anterior one uninterrupted, posterior ridge short, median in position, and arcuate with some long setae; 1 mesogastric ridge not extending laterally to anteriormost branchial marginal spines; 1 metagastric ridge not continuing laterally to anterior branchial regions. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by cervical groove, followed by 5 transverse ridges, of them 2 uninterrupted. Lateral margins convex medially, with 6 spines: 1 spine in front of and 5 spines behind anterior cervical groove; first spine anterolateral, well-developed, located at same level of lateral limit of orbit, without spine ventral to between first and anteriormost branchial spine; 2 spines on anterior branchial margin, and 3 spines on posterior branchial margin, last small. External limit of orbit with small spine; infraorbital margin with strong spine. Rostrum twice longer than broad, length 0.7 of postorbital carapace length and breadth 0.3 of carapace breadth; distance between distalmost lateral incisions 0.35 of distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with numerous short simple setae; lateral margin with 4 deeply incised sharp teeth.

Pterygostomian flap rugose, unarmed on upper margin or surface, ridges with short setae, anterior margin ending in blunt angle.

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

Abdomen: Somites 2–4 each with 2 uninterrupted; somites 5 and 6 each with 2 scale-like ridges. Males with G1 and G2.

Eyes: Ocular peduncles 1.3 times longer than broad, maximum corneal diameter 0.7 rostrum width.

Antennule: Article 1 with 3 well-developed distal spines, distodorsal larger, distomesial spine slightly smaller than distoventral. Ultimate article with a few short fine setae, not in tuft on distodorsal margin.

Antenna: Article 1 with strong distomesial spine reaching distal margin of article 2. Article 2 with 2 welldeveloped subequal distal spines, exceeding midlength of article 3. Article 3 with distodorsal spine: Article 4 unarmed.

Mxp3: Ischium with long distal spine on flexor margin, unarmed on extensor margin; crista dentata with 22 denticles. Merus as long as ischium; flexor margin with 2 spines, proximal clearly stronger than distal; extensor margin unarmed. Carpus unarmed.

P1: 3.0 times of carapace length, somewhat depressed on palm, more so on fingers, covered with finely setiferous scales, with numerous long plumose and non-plumose setae. Merus 1.2 times carapace length, 1.8 times as long as carpus, with some spines, dorsomesial and distal spines stronger than others. Carpus 0.8 length of palm, 1.5 times as long as broad; dorsal and lateral surfaces with a few spines; mesial margin with strong spines. Palm twice longer than broad, lateral and mesial margins subparallel; small spines arranged in irregular dorsolateral and dorsomesial rows; some small spines scattered on dorsal side. Fingers 0.8 times palm length, unarmed, each finger distally with 2 rows of teeth, spooned.

P2–4: moderately slender, with setose striae and sparse long plumose and non-plumose setae. P2 1.9 times of carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P3 merus, P4 merus 0.9 length of P3 merus); P2 merus 0.7 of carapace length, 3.0 times as long as broad, 1.5 times longer than P2 propodus; extensor margins each with row of 6–8 proximally diminishing spines in P2–3, 3 spines in P4; ventral margins distally ending in strong spine followed proximally by several short transverse ridges, lateral sides unarmed. Carpi each with 5 or 6 small spines on extensor margin in P2–3, 2 or 3 small spines in P4; lateral surface with granules subparalleling extensor margin; flexor distal margins acutely produced. Propodi 3.0–4.0 times as long as broad; extensor margins each with 2 proximal spines in P2–3, 1 spine in P4; flexor margins each with 5 slender movable spines. Dactyli distally ending in moderately curved strong spine, length 0.7 of propodi; flexor margins each with 5 proximally diminishing teeth, distalmost one prominent.

Epipods absent on pereiopods.

Remarks. Galathea anoplos n. sp. resembles G. connudata n. sp. from the Philippines, and Wallis and Futuna. The two species share several characters: interrupted mesogastric ridge, gastric ridges not scale-like, carapace lateral margin without spines between anterolateral spine and anteriormost branchial marginal spine, and pereiopods without epipods (differentiating characters are discussed under Remarks of G. connudata ).

No molecular data are available from G. anoplos .

Distribution. Solomon Islands, 229– 260 m.

Figures

FIGURE 9. Galathea anoplos n. sp., holotype, male, 5.2 mm, Solomon Islands (MNHN-IU- 2013 - 15867). 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, 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.