Galathea erythrina, 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 : 107-108

Galathea erythrina n.sp.

( Figs 34 , 116 F)

Material examined. Holotype: Red Sea. Saudi Arabia. Farasan Banks, Shib Radib, 18.0731°N, 40.8859°E, 7–9 m, 8 March 2013: F 1.3 mm (UF36824).

Paratype: Red Sea, Saudi Arabia. Gulf of Aqaba, 28.4039°N, 34.7407°E, 2 m, 30 September 2013: 1 F 1.5 mm (UF38147)

Etymology. From the Greek erythros, red, in relation to the color of the carapace.

Description. Carapace: 0.9 times as long as broad; transverse ridges with short fine setae and some scattered long plumose iridescent setae; cervical groove slightly distinct, laterally bifurcated; 1 epigastric ridge medially interrupted, with 2 spines; 1 protogastric ridge laterally interrupted on each side, strongly medially convex, with some long plumose iridescent setae, other ridges on gastric and anterior branchial regions scale-like or in concentric arcs; mid-transverse ridge uninterrupted, preceded by shallow cervical groove. Posterior branchial region with 3 transverse ridges, 2 of them uninterrupted. Lateral margins slightly convex medially, with 7 spines: 2 spines in front of, and 5 spines behind, anterior cervical groove; first anterolateral, second very small, without additional spine ventral to between first lateral spine and anteriormost spine of branchial margin, 2 spines on anterior branchial margin, and 3 spines on posterior branchial margin. External limit of orbit rounded; infraorbital margin with 1 spine. Rostrum broad triangular, 1.2 times as long as broad, length 0.7 postorbital carapace length and breadth 0.4 that of carapace, nearly horizontal in lateral view; distance between distalmost lateral incisions 0.2 distance between proximalmost lateral incisions; dorsal surface with a few small scale-like setiferous ridges; lateral margin with 4 deeply incised sharp teeth.

Pterygostomian flap rugose, unarmed, with sparse short setae, anterior margin blunty produced.

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

Abdomen: Somite 2 with 2 transverse ridges, anterior ridge more distinctly elevated than posterior ridge; somites 3–5 with 1 anterior ridge; somite 6 smooth.

Eyes: Ocular peduncles as long as broad, maximum corneal diameter 0.8 rostrum width.

Antennule: Article 1 with 3 well-developed spines, distodorsal larger; distomesial spine clearly smaller than others. Ultimate article with tuft of long fine setae on distodorsal margin.

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

Mxp3: Ischium with well-developed distal spine on flexor margin; extensor margin ending in blunt angle; flexor margin ending in acute angle: crista dentata with 15 denticles. Merus equally long as ischium; flexor margin with 2 spines, proximal spine slightly longer than distal spine, proximal one located at midlength, distal one at terminal end; extensor margin with small distal spine. Carpus unarmed.

P1: 2.2 times carapace length. Merus as long as carapace, twice longer than carpus, with spines arranged roughly in rows, distal spines prominent. Carpus as long as palm, 1.5 times as long as broad; dorsal surface with small spines arranged roughly in longitudinal rows; mesial margin with 1 strong spine. Palm twice longer than broad, lateral and mesial margins subparallel; spines arranged roughly in rows; dorsolateral row continuing on to lateral margin of fixed finger. Fingers as long as palm, each finger distally with two rows of teeth, spooned; mesial margin of movable finger unarmed, 1 small proximal spine on dorsal side.

P2–4: moderately slender, with setose striae and sparse long plumose setae. P2 twice carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P3 merus, P4 merus 0.8 length of P3 merus); P2 merus 0.8 carapace length, 4.3 times as long as broad, 1.1 times longer than P2 propodus. Extensor margin with row of 7 or 8 proximally diminishing spines on P2–3, 3 spines on P4; ventral margins distally ending in strong spine followed proximally by 0–2 spines and several eminences, lateral sides unarmed. Carpi with 3 spines on extensor margin on P2–3, unarmed on P4; lateral surface with 2 or 3 acute granules sub-paralleling extensor margin; flexor distal margin acute. Propodi 4.5–5.0 times as long as broad; extensor margin with 2–4 proximal spines on P2–3, unarmed on P4; flexor margin with 4 slender movable spines. Dactyli distally ending in well-curved strong spine, length 0.6 that of propodi; flexor margin with 4 proximally diminishing teeth, terminal one prominent.

Epipods absent on pereiopods.

Coloration. Carapace and abdomen reddish; median white spots on abdominal somites 2–4. P1–4 with whitish and greenish bands; some P1 spines with red tip. P2-4 meri each with orange spot on distal part.

Remarks. Galathea erythrina is closely related to G. anouchkae n. sp. from New Caledonia, Chesterfield Islands, Vanuatu and Fiji. G. er y t h r i n a is easily distinguished from G. anouchkae by the shape of the anterior protogastric ridge. This ridge is medially convex in G. erythrina , instead of straight in the other species.

The species is also close to G. ceti n. sp. from Papua New Guinea and New Caledonia (see under Remarks of G. ceti ).

No genetic data are available for G. erythrina .

Distribution. Red Sea, Gulf of Aqaba, Farasan Banks; 2– 9 m.

Figures

FIGURE 34. Galathea erythrina n. sp., holotype, female, 1.3 mm, Western Australia (UF 36824). 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.

FIGURE 116. Dorsal view. A, Galathea boucheti n. sp., Madagascar, holotype, male 4.0 mm (MNHN-IU- 2013 - 8110). B, Galathea caesariata n. sp., Vanuatu, holotype, male 5.0 mm (MNHN-IU- 2013 - 15938). C, Galathea celiae n. sp., Red Sea, male 2.8 mm (UF 32860). D, Galathea consobrina De Man, 1902, Vanuatu, female 3.2 mm (MNHN-IU- 2013 - 8386). E, Galathea cymo n. sp., Vanuatu, ovigerous female 4.0 mm (MNHN-IU- 2013 - 13343). F, Galathea erythrina n. sp., Red Sea, holotype, female 1.3 mm (UF 36824). G, Galathea eulimene n. sp., Red Sea, Saudi Arabia, male 3.1 mm (UF 35961). H, Galathea galene n. sp., ovigerous female 5.4 mm (MNHN-IU- 2013 - 9878). I, Galathea gladiola n. sp., Vanuatu, holotype, female 4.5 mm (MNHN-IU- 2013 - 8436).