Galathea politula, 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 : 239-241

Galathea politula n. sp.

( Figs 86 , 119 E)

Material examined. Holotype: Vanuatu. SANTO, Stn AT39, 15°22.4'S, 167°12.6'E, 57–81 m, 27 September 2006: M 3.5 mm (MNHN-IU-2013-9707).

Paratypes: New Caledonia, Lagon. Stn DW1234, 22°24.05'S, 166°55.08'E, 52 m, 9 March 1993: 1 F 4.3 mm (MNHN-IU-2013-15871).

Vanuatu. SANTO, Stn FR10, 15°36.9'S, 167°10.5'E, 6–33 m, 15 September 2006: 2 M 1.9–4.0 mm, 2 ov. F 2.8–3.4 mm (MNHN-IU-2013-15872).—Stn DR35, 15°31.4'S, 167°09.7'E, 4–18 m, 18 September 2006: 2 M 2.5–3.7 mm (MNHN-IU-2013-15868).— Stn AT38, 15°21.4'S, 167°12.8'E, 29–58 m, 27 September 2006: 3 ov. F 3.0– 3.4 mm (MNHN-IU-2013-9711).—Stn AT39, 15°22.4'S, 167°12.6'E, 57–81 m, 27 September 2006: 1 ov. F 2.8 mm (MNHN-IU-2013-15870).— Stn AT52, 15°31.5'S, 167°12.7'E, 52–62 m, 2 October 2006: 1 M 3.3 mm (MNHN-IU-2013-9709).—Stn FP47, 15°32.4'S, 167°12.7'E, 45–50 m, 2–3 October 2006: 1 M 1.8 mm (MNHN- IU-2013-9710).—Stn AT75, 15°37.0/37.3'S, 167°09.2/09.6'E, 52–66 m, 10 October 2006: 1 M 3.6 mm (MNHN- IU-2013-9713), 1 ov. F 3.4 mm (MNHN-IU-2013-9712).—Stn AT80, 15°31.7'S, 167°10.8'E, 36–43 m, 12 October 2006: 1 M 3.1 mm (MNHN-IU-2013-9708), 1 M 3.5 mm (MNHN-IU-2013-15869).

Etymology. Fom the Latin politus, smooth, in reference to the smooth carapace surface.

Description. Carapace: as broad as long; transverse ridges with dense short setae, and some scattered long plumose setae; cervical groove distinct, laterally bifurcated. One small hepatic spine near first marginal spine (anterolateral). Gastric region with some transverse ridges: 1 epigastric ridge uninterrupted, unarmed, followed by some scale-like short ridges; 1 protogastric ridge medially interrupted, unarmed; 2 mesogastric ridges, anterior ridge uninterrupted, not extending laterally to anteriormost of branchial marginal spines, posterior ridge scale-like or uninterrupted; 2 metagastric ridges, anterior ridge uninterrupted usually continuing laterally with anterobranchial ridge, posterior ridge uninterrupted and short. Anterior branchial region with distinct ridges. Midtransverse ridge uninterrupted, preceded by shallow cervical groove, followed by 6 ridges, 3 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 same level of lateral limit of orbit, second, small, at midlength between anterolateral spine and anteriormost spine of branchial margin, with 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 1.8 times as long as broad, length 0.6 postorbital carapace length and breadth 0.3 that of carapace; distance between distalmost lateral incisions 0.30 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with numerous short unirramous setae and long plumose setae; lateral margin with 4 deeply incised sharp teeth.

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

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

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

Eyes: Ocular peduncles 1.3 times longer than broad, maximum corneal diameter 0.8 rostrum width.

Antennule: Article 1 with 3 well-developed distal spines, distodorsal larger, distomesial spine smaller than others. 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 3. Article 2 with 2 welldeveloped distal spines, distolateral spine longer than distomesial and exceeding midlength of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with long distal spine on flexor margin, unarmed on extensor margin; crista dentata with 19–21 denticles. Merus as long as ischium; flexor margin with 3 spines, proximal slightly longer than others; extensor margin with 1 small distal spine. Carpus with 2 or 3 acute granules along extensor margin.

P1: 3.2 times carapace length, somewhat depressed on palm, more so on fingers, covered with finely setiferous scales, with numerous long plumose setae. Merus 1.2 times carapace length, 1.5 times as long as carpus, with some spines, dorsomesial and distal spines stronger than others. Carpus 0.8 length of palm, twice longer than broad; dorsal and lateral surfaces with a few spines; mesial margin with 5 spines (median strong). Palm 2.3 times longer than broad, lateral and mesial margins subparallel; small spines arranged roughly in dorsolateral and dorsomesial rows, some small spines scattered on dorsal side. Fingers slightly longer than palm, unarmed, each finger distally with two rows of teeth, spooned.

P2–4: moderately slender, with setose striae and sparse long plumose setae. P2 1.9 times carapace length. Meri successively shorter posteriorly (P3 merus 0.8 length of P3 merus, P4 merus 0.7 length of P3 merus); P2 merus 0.8 carapace length, 4.7 times as long as broad, 1.5 times longer than P2 propodus. Extensor margin with row of 7–9 proximally diminishing spines on P2–3, 1 distal spine on P4; ventral margins distally ending in strong spine followed proximally by 0–2 spines and several eminences, lateral sides unarmed; distoventral spine on P2 only. Carpi with 4 or 5 small spines on extensor margin on P2–3, unarmed on P4, distalmost (sometimes absent) smaller than distal second; lateral surface with granules sub-paralleling extensor margin; flexor distal margin acute. Propodi 4.3–4.6 times as long as broad; extensor margin with 2 proximal spines on P2, unarmed on P3–4; flexor margin with 5–7 slender movable spines. Dactyli distally ending in wellcurved strong spine, length 0.5–0.6 that of propodi; flexor margin with 5 or 6 proximally diminishing teeth, terminal one prominent.

Epipods absent on pereiopods.

Coloration. Base color translucent light orange. Ridges on carapace and abdomen reddish. Rostrum whitish. P1 with distal part of merus, carpus and palm dark orange, base of fingers with white fleck. P2–4 with whitish band on distal part of merus, carpus and propodus.

Remarks. Galathea politula n. sp. belongs to the group of species having the anterior mesogastric ridge interrupted, the carapace lateral margin bearing a small spine between the anterolateral and the anteriormost branchial marginal spines, non-scale-like gastric ridges, the absence of epigastric spines, the antennular article 1 bearing three terminal spines, and the lack of pereiopodal epipods. The closest relative is G. l e n i s Baba, 1969 from Japan, from which it is easily distinguished by the following features:

- The anterior metagastric ridge continues to the anterior branchial ridges in the new species, whereas this ridge does not continue in G. l e n i s.

- The antennal article 1 has the distomesial spine not reaching the distal margin of the article 2 in G. politula , whereas this spine reaches the distal margin of the article 3 in G. lenis .

Distribution. Vanuatu, New Caledonia; 4– 81 m.

Figures

FIGURE 86. Galathea politula n. sp., holotype, male, 3.5 mm, Vanuatu (MNHN-IU- 2013 - 9707). 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, 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.

FIGURE 119. Dorsal view. A, Galathea pilosa De Man, 1888, Papua New Guinea, ovigerous female 4.5 mm (MNHN-IU- 2013 - 1055). B, Galathea pilosa De Man, 1888, Maldives, male 3.6 mm (UF 39675). C, Galathea platycheles Miyake, 1953, Madagascar, female 2.2 mm (MNHN-IU- 2013 - 13822). D, Galathea platycheles Miyake, 1953, Western Australia, ovigerous female 1.9 mm (UF 22402). E, Galathea politula n. sp., Vanuatu, holotype, M 3.5 mm (MNHN-IU- 2013 - 9707). F, Galathea polydora n. sp., Vanuatu, male 3.3 mm, (MNHN-IU- 2013 - 9871). G, Galathea polydora n. sp., Vanuatu, ovigerous female 2.5 mm (MNHN-IU- 2013 - 13476). H, Galathea polyphemus n. sp., French Polynesia, male 4.4 mm (UF 15427). I, Galathea providentia Laurie, 1926, Madagascar, female 3.0 mm (MNHN-IU- 2013 - 13802).