Galathea setigera, 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 : 283-285

Galathea setigera n. sp.

( Fig. 102 )

Material examined. Holotype: Indonesia. Kei Islands. KARUBAR, Stn CP16, 05°17'S, 132°50'E, 315–349 m, 24 October 1991: ov. F 6.8 mm (MNHN-IU-2013-8325).

Paratypes: Indonesia. Kei Islands. KARUBAR, Stn ED11, 05°23'S, 132°30'E, 360–368 m, 23 October 1991: 1 M 5.0 mm (MNHN-IU-2013-8334). Stn CP16, 05°17'S, 132°50'E, 315–349 m, 24 October 1991: 1 M 5.4 mm (MNHN-IU-2013-8326).

Etymology. From the Latin, setiger, bearing bristles, in reference to the pilosity of the carapace.

Description. Carapace: As long as broad; dorsal surface nearly horizontal from anterior to posterior. Dorsal surface covered by fine simple and non-iridescent setae, lacking distinct long transverse ridges, except midtransverse and posterior ridges and a few scattered scale-like or short ridges on posterior half. Mid-transverse ridge preceded by shallow cervical groove. Epigastric region with 2 or 3 pairs of small spines. Anterior branch of cervical groove distinct. Lateral margins slightly convex medially, with 6 spines: 1 spine in front of and 5 spines behind anterior cervical groove; first anterolateral, well-developed, at level of lateral limit of orbit; 2 spines on anterior branchial region, and 3 spines on posterior branchial margin, last small. Well-developed spine on lateral limit of orbit; infraorbital margin with some minute spines. Rostrum 1.4 as long as broad, length 0.5 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, slightly concave, with some short setae; lateral margin with 4 deeply incised sharp teeth.

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

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

Abdomen: Somites 2–4 each with 2 uninterrupted transverse ridges on tergite; somites 5 and 6 smooth; posteromedian margin of somite 6 straight. Telson completely subdivided, with 7 plates. Males with G1 and G2.

Eyes: Ocular peduncles 1.5 times longer than broad, maximum corneal diameter 0.6 rostrum width.

Antennule: Article 1 with 3 spines; well-developed distodorsal and distolateral spines, distodorsal larger than others. Ultimate article with a few long fine setae not in tuft on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine, reaching distal margin of article 2. Article 2 with 2 welldeveloped distal spines, distolateral spine longer than distomesial and reaching end of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with well-developed spine on flexor distal margin; extensor margin ending in acute angle; crista dentata with 25–27 denticles. Merus as long as ischium; flexor margin with 2 spines, proximal longer than distal; extensor margin unarmed. Carpus unarmed.

P1: 1.8–2.0 times carapace length, covered with finely setiferous scales, and some scattered long plumose setae. Merus 0.7 times length of carapace, twice longer than carpus, with spines arranged roughly in rows, dorsomesial spines stronger; distal spines prominent. Carpus 0.9 length of palm, 1.7 times as long as broad; dorsal surface with some small spines; mesial margin with row of well-developed spines. Palm twice longer than broad, lateral and mesial margins subparallel; a few small spines arranged roughly in dorsolateral and dorsomesial rows, some small spines scattered on dorsal side; dorsolateral spines continuing along fixed finger. Fingers as long as palm, each finger distally with two rows of teeth, spooned; movable finger unarmed.

P2–4: moderately slender, with setose striae and some long non-plumose setae. P2 1.8 times carapace length. Meri successively shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus 0.8 carapace length, 4.2 times as long as broad, 1.7 times longer than P2 propodus; P3 merus 3.0 times longer than broad, 1.4 times longer than P3 propodus; P4 merus 3.0 times as long as broad, 1.2 length of P4 propodus. Extensor margin of P2–3 meri with row of 14 or 15 proximally diminishing spines, and 1 or 2 spines on P4; ventral margins distally ending in strong spine followed proximally by several tubercles or eminences; lateral sides unarmed. Carpi with 4 or 5 spines on extensor margin on P2–4; lateral surface with 4–6 spines or acute granules sub-paralleling extensor margin on P2–4; flexor distal margin ending in acute angle. P2–4 propodi 4.0–4.4 times as long as broad; extensor margin with 3 or 4 proximal spines; flexor margin with 5 or 6 slender movable spines on P2–4. Dactyli distally ending in well-curved strong spine, length 0.5–0.6 that of propodi; flexor margin with 4 or 5 proximally diminishing teeth, terminal one prominent.

Epipods absent on pereiopods.

Remarks. Galathea setigera n. sp. is closest to G. kuboi from Japan, Philippines, and Indonesia, and G. nuda n. sp. from French Polynesia and Chesterfield Islands. In these three species most of dorsal ridges on the carapace are obsolescent. They can be easily distinguished by the following characters:

- In G. kuboi , the distal spine on the flexor margin of the Mxp3 merus is subequal in the size to the proximal spine, rather than smaller than the proximal spine in G. nuda and G. setigera .

- The epipods are present on P 1 in G. nuda , rather than absent from all pereiopods in G. setigera and G. kuboi .

- The rostrum is elongate and more than 1.5 times longer than broad in G. nuda , whereas the rostrum is short and less or equal than 1.5 times longer than broad in G. setigera and G. kuboi .

- The gastric region on the carapace has some scale-like ridges in G. nuda , but these ridges are absent in G. setigera and G. kuboi .

No genetic data are available for G. setigera .

Distribution. Indonesia, Kei Islands, 315– 368 m.

Figures

FIGURE 102. Galathea setigera n. sp., holotype, ovigerous female, 6.8 mm, Indonesia, Kei Islands (MNHN-IU- 2013 - 8325). 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.