Galathea rhaphidia, 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 : 266-268

Galathea rhaphidia n. sp.

( Fig. 95 )

Material examined. Holotype: Wallis and Futuna. MUSORSTOM 7, Stn DW610, 13°21,5'S, 176°08,9'W, 286 m, 26 May 1992: ov. F 5.3 mm (MNHN-IU-2013-8494).

Paratypes: Fiji. MUSORSTOM 10, Stn CP1348, 17°30.29'S, 178°39.63'E, 353–390 m, 11 August 1998: 1 M 5.8 mm (MNHN-IU-2013-8499).—Stn CP1389, 18°18.58'S, 178°04.73'E, 241–417 m, 19 August 1998: 1 ov. F 4.9 mm (MNHN-IU-2013-8495). BORDAU 1, Stn CP1407, 16°39.67’S, 179°38.69'E, 499–525 m, 25 February 1999: 1 F 5.6 mm (MNHN-IU-2013-8497).—Stn CP1446, 17°11.34'S, 178°42.03'W, 350–367 m, 3 March 1999: 2 ov. F 5.9–6.1 mm (MNHN-IU-2013-8502).

Tonga. BORDAU 2, Stn CP1511, 21°08'S, 175°22'W, 384–402 m, 31 May 2000: 1 ov. F 6.0 mm (MNHN-IU- 2013-8498).—Stn CP1578, 19°42'S, 174°25'W, 329–331 m, 11 June 2000: 1 M 3.8 mm (MNHN-IU-2013-8496).

Etymology. From the Greek rhaphis, needle, in reference to the shape of the rostrum.

Description. Carapace: 1.2 times longer than broad; transverse ridges with dense short setae, without long setae; cervical groove distinct, laterally bifurcated. Gastric region with some transverse ridges: 1 epigastric ridge, scale-like, with 6–9 small spines; 2 protogastric ridges, anterior ridge uninterrupted, medially convex, with 1 parahepatic spine on each side, posterior uninterrupted; 2 mesogastric ridges, anterior ridge uninterrupted and not extending laterally to anteriormost of branchial marginal spines, posterior ridge short; 2 metagastric ridges, anterior ridge uninterrupted, not extending laterally to anteriorbranchial ridge, posterior ridge short. Hepatic region with 1 spine near anterolateral spine. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove. Posterior branchial region with 6 transverse ridges, 1 ridge uninterrupted. Lateral margins subparallel, with 7 or 8 spines: 2 spines in front of and 5 or 6 spines behind anterior cervical groove; first anterolateral, well-developed, slightly behind level of lateral limit of orbit, 1 small spine at midlength between anterolateral spine and anterior cervical groove, with small spine ventral to between first and second; 2 or 3 small spines on anterior branchial region, and 2 or 3 spines on posterior branchial margin. Small spine on lateral limit of orbit, 1 small frontal spine between orbit and anterolateral spine; infraorbital margin with some small spines. Rostrum narrow, 3.2 times as long as broad, length 0.7 postorbital carapace length and breadth 0.3 that of carapace; distance between distalmost lateral incisions 0.25 distance between proximalmost lateral incisions; dorsal surface flatish, with numerous small scale-like setose ridges; lateral margin with 4 shallowly incised teeth.

Pterygostomian flap rugose, unarmed, ridges with short setae, anterior margin acute; upper margin, near linea anomurica, with numerous small teeth.

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

Abdomen: Somites 2–4 each with 2 uninterrupted ridges, and some scattered short scales; somite 6 with 2 medially interrupted ridges. Males with G1 and G2.

Eyes: Ocular peduncles 1.8 times longer than broad, maximum corneal diameter 0.9 rostrum width.

Antennule: Article 1 with 2 well-developed distal spines, distodorsal larger, distomesial obsolescent; 3 small spines along lateral margin. Ultimate article with tuft of long fine setae on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine not reaching end of article 2. Article 2 with 2 distal spines, distolateral spine longer than distomesial, and barely reaching end of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with flexor margins ending in small spine, extensor margin ending in acute angle; crista dentata with 20 or 21 denticles. Merus as long as ischium; flexor margin with 3 spines, proximal spine clearly longer than others, median spine smaller than distal; extensor margin ending in small spine. Carpus unarmed.

P1: 4.4–4.5 times carapace length, with numerous setiferous small scales, and some scattered long setae.

Merus 2.0 times carapace length, 1.8 times as long as carpus, with numerous spines, dorsomesial and distal spines stronger than others. Carpus 0.8 length of palm, 5.6 times as long as broad; dorsal surface with some small spines; mesial margin with row of spines. Palm 5.9 times longer than broad, lateral and mesial margins subparallel; small spines arranged roughly in dorsal, dorsolateral and dorsomesial rows. Fingers 0.7 times palm length, each finger distally with two rows of teeth, spooned; fingers unarmed.

P2–4: long and slender, with some setose striae and sparse long setae. P2 2.5 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 as long as carapace, 8.2 times as long as broad, 1.1 times longer than P2 propodus. P3 merus 5.7 times as long as broad, 1.0 times longer than P3 propodus. P4 merus 3.6 times as long as broad, 0.9 times longer than P4 propodus. Extensor margin with row of 10–12 proximally diminishing spines on P2–3, 4 or 5 small spines on P4; ventral margins distally ending in strong spine, lateral sides with row of small spines on P2–3. Carpi with 5–7 spines on extensor margin on P2–3; lateral surface with 5 or 6 small spines sub-paralleling extensor margin; flexor distal margin acute. Propodi 10.5 (P2), 8.0 (P3), 6.0 (P4) times as long as broad; extensor margin with 4 or 5 small proximal spines; flexor margin with 8 or 9 slender movable spines, distal two spines with another smaller spine mesial them. Dactyli distally ending in well-curved strong spine, length 0.5 that of propodi; flexor margin with 8 or 9 proximally diminishing teeth, ultimate and penultimate distal teeth usually subequal in size in P2.

Epipods present on P1.

Remarks. The new species is closely related to G. inconspicua Henderson, 1885 and other species, e.g. G. perone n. sp., G. scolopia n. sp., with extremely narrow rostrum and 2 well-developed distal spines on antennular article 1 (see Remarks of G. inconspicua ).

Distribution. Fiji, Tonga, Wallis and Futuna; 286– 525 m.

Figures

FIGURE 95. Galathea rhaphidia n. sp., holotype, ovigerous female, 5.3 mm, Wallis and Futuna (MNHN-IU- 2013 - 8494). 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, left P 2 dactylus, lateral view; H, right P 3, lateral view; I, right P 4, lateral view. Scale: A, E, F, H, I = 1 mm; B – D, G = 0.5 mm.