Galathea longimanoides Johnson, 1970

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 : 172-174

Galathea longimanoides Johnson, 1970

( Fig. 61 )

Galathea longimanoides Johnson, 1970: 6 , figs 1c–h (Johore Shoals, Singapore, 18 m).— Komai, 2000: 353 (list).—Baba et al., 2008: 72 (compilation).

Material examined. Th. Mortensen, Thailand, N of Koh Chuen Island, 28 m, 5 February 1900: 1 M 6.9 mm, 1 ov. F 4.7 mm ( ZMUC CRU- 11233).

Vietnam. No exact locality, 12–24 m, 26 May 2012: 1 ov F 3.6 mm ( OIRAS).

Description. Carapace: As long as broad; transverse ridges with numerous short fine setae, without long setae; cervical groove distinct, laterally bifurcated. Gastric region with 8 ridges; 2 epigastric ridges, anterior ridge with 2 median spines, posterior ridge scale-like; 2 protogastric uninterrupted ridges, 1 small parahepatic spine on each side of anterior ridge; 2 mesogastric uninterrupted ridges, anterior one not continuing laterally with anterior branchial ridges; 2 metagastric ridges, uninterrupted, anterior ridge extending laterally with anterior branchial ridges (not very clear in specimen figured). Hepatic region with 1 small spine on each side. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 5 ridges, 3 of them uninterrupted. Lateral margins slightly convex medially, with 7 spines: first anterolateral, well-developed, second very small but distinct, located at midlength between first spine and anteriormost spine of branchial margin, with small spine ventral to between first and second; 2 spines on anterior branchial margin, and 3 spines on posterior branchial margin. Small outer orbital spine; infraorbital margin with 1 strong spine. Rostrum triangular, twice as long as broad, length 0.5 that of, 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 some thick long plumose setae; lateral margin with 4 shallowly incised spines.

Pterygostomian flap rugose, with sparse short setae, anterior margin bluntly angular.

Sternum: About as long as broad, lateral limits divergent posteriorly.

Abdomen: Somites 2–4 each with 4 uninterrupted transverse ridges on tergite, anterior ridge more elevated than posterior ridge; somites 5 and 6 each with 2 medially interrupted ridges, posteromedian margin of somite 6 slightly convex.

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

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

Antenna: Article 1 with distomesial spine reaching distal margin of article 2. Article 2 with distolateral spine longer than distomesial and exceeding midlength of article 3. Article 3 with small distomesial spine. Article 4 unarmed.

Mxp3: Basis with several denticles on mesial ridge, distalmost larger. Ischium with well-developed spine on flexor distal margin; crista dentata with 24 or 25 denticles. Merus slightly longer than ischium; flexor margin with 2 subequal spines, sometimes 1 minute spine between them; extensor margin with minute distal spine. Carpus unarmed.

P1: 3.5–4.0 times carapace length, with numerous finely setiferous scales, with scattered long thick setae. Merus 1.2 times length of carapace, twice as long as carpus, with spines arranged roughly in rows, dorsomesial and ventromesial spines stronger; distal spines prominent. Carpus 0.7 length of palm, 3 times as long as broad; dorsal surface with small spines arranged roughly in longitudinal rows; mesial spines slightly stronger than dorsal spines. Palm 3.5–3.8 times longer than broad, lateral and mesial margins with minute spines arranged roughly in dorsolateral and dorsomesial rows, some minute spines scattered on dorsal side. Fingers as long as palm, each finger distally ending in two rows of incurved teeth to cross each other when closed, mesial margin of movable finger and lateral margin of fixed finger unarmed.

P2–4: Moderately long and slender, with setose striae and long setae. P2 twice carapace length. Meri successively shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus 0.7 carapace length, 5 times as long as broad, 1.3 times longer than P2 propodus; P3 merus 5 times longer than broad, 1.2 times longer than P3 propodus; P4 merus 4 times as long as broad, as long as P4 propodus. Extensor margins of P2–3 meri with row of 10 or 11 proximally diminishing spines, P4 merus with 2–4 minute spines and 2 small dorsal spines; flexor margins distally ending in strong spine followed proximally by 1 or 2 small spines and several tubercles or eminences. P2–3 carpi with 5 small spines on extensor margin, 3 or 4 minute spines on P4; lateral surface with some small spines and acute granules sub-paralleling extensor margin on P2–4; flexor distal margin sometimes with small spine. P2–4 propodi 5.5 times as long as broad, respectively; extensor margin with 2 or 3 proximal spines; flexor margin with 4–7 slender movable spines on P2–4. Dactyli subequal in length, distally ending in well-curved strong spine, length half of propodi; flexor margin with 4–6 proximally diminishing teeth, terminal one prominent.

Epipods absent on pereiopods.

Remarks. Galathea longimanoides was described on the basis of one male and one ovigerous female from Johore Shoals, Singapore. The original description is short, acompanied by a few illustrations. The types were lost (P.F. Clark, NHMUK, personal communication) and we failed to obtain topotypic material. Therefore, our identification is considered to be still provisional until topotypic material becomes available. The present material, however, closely agrees well with the original description by Johnson (1970). If our identification is correct, G. longimanoides most closely resembles G. ceti n. sp. from Papua New Guinea and New Caledonia, and G. minutiae n. sp. from New Caledonia. These three species can be differentiated by the different structure of P1 fingers. The P1 fingers distally end in incurved spines to cross each other when closed in G. longimanoides , whereas they are distally spooned and not cross distally in the latter two species.

No genetic data are available for this species.

Distribution. The type locality is Johore Shoals, Singapore, 18 m, associated with crinoids. Present records from Thailand and Vietnam, 12– 28 m.

Figures

FIGURE 61. Galathea longimanoides Johnson, 1970. A, E, male 6.9 mm; B-D, F-G, ov. F 4.7 mm, Thailand (ZMUC CRU- 11233). A, carapace, 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 carpus, palm and fingers, dorsal view; F, right P 2, lateral view; G, right P 2 dactylus, lateral view. Scale: A, F = 1 mm; E = 2 mm; B – D, G = 0.5 mm.