Galathea eupompe, 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 : 114-116

Galathea eupompe n.sp.

( Fig. 37 )

Material examined. Holotype: Australia. Queensland. Lizard Island, Washing Machine, 14.3902°S, 145.2737°E, 10–12 m, 12 February 2009: M 3.5 mm (QM W29207).

Paratypes: Australia. Queensland. Lizard Island, Washing Machine, 14.3902°S, 145.2737°E, 10–12 m, 12 February 2009: 1 ov. F 3.5 mm (UF16837), 1 M 3.0 mm (UF16842).

Australia. Queensland, Lizard Island, 1 M 2.4 mm, 1 ov. F 3.3 mm (UF16914).

Etymology. The name Eupompe , good voyage, 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 slightly distinct, laterally bifurcated. Gastric region with 7 or 8 transverse ridges: 1 epigastric ridge with 2 spines, medially interrupted; 2 protogastric ridges, anterior uninterrupted, convex medially, with 1 parahepatic spine on each side, posterior ridge moderately short, sometimes with a few long setae; 2 mesogastric ridges, anterior uninterrupted, not extending laterally to anteriormost of branchial marginal spines, posterior ridge interrupted; 2 metagastric ridges, anterior uninterrupted and continuing along anterior branchial region, posterior ridge moderately short; sometimes 1 additional short metagastric ridge. Hepatic region unarmed. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 5 ridges. Lateral margins 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, slightly mesial to carapace margin, 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 1.5 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 short unirramous setae; lateral margin with 4 deeply incised sharp teeth.

Pterygostomian flap rugose, with spine on anterior surface, ridges with short setae, anterior margin acute.

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

Abdomen: Somites 2–3 each with 3 or 4 uninterrupted transverse ridges on tergite, and some short scattered scale-like ridges; somite 4 with 2 uninterrupted and 2 interrupted ridges; somite 5 with 2 uninterrupted ridges; somite 6 with 2 medially interrupted ridges, posteriormedian margin slightly convex. 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 smaller than others. Ultimate article with tuft of fine setae on distodorsal margin.

Antenna: Article 1 with strong distomesial spine exceeding distal margin of article 2. Article 2 with 2 welldeveloped subequal distal spines, nearly reaching end of article 3. Article 3 with small distomesial spine, sometimes absent. Article 4 unarmed.

Mxp3: Ischium with flexor margin ending in strong spine, extensor margin ending in acute angle; crista dentata with 23 or 24 denticles. Merus slightly shorter than ischium; flexor margin with 2 strong subequal spines; extensor margin with small distal spine. Carpus rugose along extensor margin.

P1: 2.8 times carapace length, with numerous setiferous scales, and a few scattered long setae. Merus as long as carapace, 1.7 times as long as carpus, with some spines, dorsomesial and distal spines stronger than others. Carpus 0.9 times length of palm, 1.6 times as long as broad; dorsal surface with some small spines; mesial margin with 4 spines, distal second strongest. Palm 1.6 times longer than broad, lateral and mesial margins slightly convex; spines arranged roughly in dorsolateral and dorsomesial rows, and some small spines on dorsal side; dorsolateral row continuing along fixed finger. Fingers 0.8 times palm length, each finger distally with two rows of teeth, spooned.

P2–4: Moderately long and slender, with some setose striae and sparse long plumose setae. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.8 length of P3 merus). P2 1.7 times carapace length. P2 merus 0.6 carapace length, 3.1 times as long as broad, 1.4 times longer than P2 propodus; P3 merus 3.0 times longer than broad, 1.3 times longer than P3 propodus, P4 merus 2.8 times longer than broad, 1.2 times longer than P4 propodus. Extensor margin of P2–3 meri with row of 10 proximally diminishing spines, 1 distal spine on P4; ventral margins distally ending in strong spine followed proximally by 0–1 spines or several eminences; lateral sides unarmed on P2–3, and with 3 or 4 spines on P4. Carpi with 4 spines on extensor margin on P2–3, distalmost smaller than distal second, and sometimes absent, 1 small distal spine on P4; lateral surface with some small spines or acute granules sub-paralleling extensor margin on P2–4; flexor distal margin ending in acute angle. P2–4 propodi 2.8–3.2 times as long as broad; extensor margin with 2 proximal small spines on P2–3, unarmed on P4; flexor margin with 4 or 5 slender movable spine. Dactyli distally ending in well-curved strong spine, length 0.6 that of propodi; flexor margin with 4 or 5 proximally diminishing teeth, terminal one prominent.

Epipods present only on P1.

Remarks. Galathea eupompe n. sp. belongs to the group of species having 2 epigastric spines, one small spine between the anterolateral and anteriormost branchial marginal spines, non-scale-like gastric ridges, three welldeveloped distal spines on the antennular basal article, one facial spine on the pterygostomian flap, and epipods only on P1. The closest relatives are G. corallicola Haswell, 1882 from Australia, G. coralliophilus Baba & Oh, 1990 from the Gulf of Thailand, Singapore, South China Sea, and Taiwan and G. orientalis Stimpson, 1858 from Japan to Australia.

Galathea eupompe is easily differentiated from G. coralliophilus by the following features:

- The carapace dorsal surface has scattered feathered setae in G. coralliophilus , but such setae are absent in G. eupompe .

- The carapace has one scale-like median ridge behind the protogastric ridge in G. coralliophilus , which is absent in G. eupompe .

Galathea eupompe is distinguished from G. corallicola and G. orientalis by the presence of parahepatic spines, which are absent in G. corallicola and G. orientalis .

The genetic divergences with G. orientalis is 12.9%, (COI) ( Tab. 1). Distribution. Australia, Queensland (Lizard Island), 10– 12 m.

Figures

FIGURE 37. Galathea eupompe n. sp., holotype, male, 3.5 mm, Australia, Queensland (QM W 29207). 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, 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.