Galathea longimana

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 : 170-172

Galathea longimana Paul’son, 1875

( Fig. 60 )

Galathea longimana Paul’son, 1875: 94, pl. 12, figs 2, 2a (Red Sea, Sinai, Ras Muhammad).— Benedict, 1902: 302 (list).— Nobili, 1906: 128 (Red Sea).— Doflein & Balss, 1913: 169 (no record).— Gurney, 1938: 82, pl. 6, figs 58–68 (Ghardaqa, Egypt).— Lewinsohn, 1967: 175.—Baba et al., 2008: 72 (in part, compilation).

Galathea australiensis .— Balss, 1915: 2 (Red Sea).

Not Galathea longimana .— Lewinsohn, 1969: 107, fig. 20 (Red Sea, 0–3 m) (= G. eulimene n. sp.).

Material examined. Red Sea. Suez Gulf. Stn 5, 8 December 1928: 1 M 2.7 mm (MNHN-Ga758, MNHN-IU- 2013-9686), 1 M 2.5 mm (MNHN-Ga759, MNHN-IU-2013-9687).—Stn 10, 8 December 1928: 2 M 2.1–2.3 mm, 2 ov. F 2.0– 2.4 mm (MNHN-Ga756, MNHN-IU-2013-9676).—Stn 11, 8 December 1928: 1 M 2.2 mm, 2 ov. F 3.0– 3.1 mm (MNHN-Ga757, MNHN-IU-2013-9688), 1 M 2.3 mm 3 ov. F 2.2–3.3 mm (MNHN-Ga755, MNHN- IU-2013-9690), 2 M 3.0 mm (MNHN-Ga760, MNHN-IU-2013-9689), 1 M 4.1 mm (MNHN-IU-2013- 14171).—Stn 12, 9 December 1928: 1 F 2.6 mm (MNHN-Ga754, MNHN-IU-2013-9691).

Description. Carapace: As long as broad; ridges with dense short setae, without long setae; cervical groove laterally bifurcated; ridges on gastric and anterior branchial regions scale-like or in concentric arcs; epigastric and protogastric regions with 2 median spines; 1 parahepatic and 1 lateral protogastric on each side; 2 median protogastric spines and 1 anterior branchial spine on each side. Mid-transverse ridge laterally interrupted, preceded by shallow cervical groove, followed by 5 transverse ridges, 2 ridges uninterrupted. Lateral margins slightly convex medially, with 8 spines: 2 spines in front of and 6 spines behind anterior cervical groove; anterolateral spine well-developed, second spine small, located at midlength between anterolateral spine and anteriormost spine of branchial margin; additional spine ventral to between first and second lateral spine; 3 spines on anterior branchial margin, and 3 spines on posterior branchial margin, last smaller than others. External limit of orbit acute; infraorbital margin with 1 strong spine. Rostrum moderately elongate, triangular, 1.6–1.9 times as long as broad, 0.6 carapace length and breadth 0.4 that of carapace, nearly horizontal in lateral view; distance between distalmost lateral incisions 0.25 distance between proximalmost lateral incisions; dorsal surface with small setiferous ridges; lateral margin with 4 deeply incised sharp teeth.

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

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

Abdomen: Somites 2–4 each with 2 transverse ridges on tergite, anterior ridge more distinctly elevated than posterior ridge; somites 5 and 6 with 2 medially interrupted ridges, posteromedian margin of somite 6 distinct, nearly straight. 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 spines, distodorsal larger; distomesial spine somewhat smaller and more slender than distolateral. Ultimate article with a few setae, not in tuft, on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine exceeding distal margin of article 2. Article 2 with 2 subequal well-developed distal spines, overreaching midlength of article 3. Article 3 with minute distomesial spine. Article 4 unarmed.

Mxp3: Ischium with small distal spine on flexor margin; extensor margin with small but distinct distal spine; crista dentata with 21–23 denticles. Merus as long as ischium; flexor margin with 2 strong spines of subequal size; extensor margin with 2 minute spines. Carpus unarmed.

P1: 3.0–4.0 times carapace length, relatively slender,and spinose, with numerous short and long setae. Merus as long as carapace, 1.3 times as long as carpus, with spines arranged roughly in rows, mesial and distal spines strong. Carpus 0.7 length of palm, 2.6 times as long as broad (breadth measured at midlength); dorsal surface with spines arranged roughly in longitudinal rows; mesial margin with 2–4 well-developed spines (distal second largest). Palm 2.5–2.9 times longer than broad, lateral and mesial margins subparallel; spines arranged roughly in rows, dorsolateral row of spines continued on to whole lateral margin of fixed finger. Fingers 0.7 length of palm, distally crossing when closed, 2 terminal spines of fixed finger accommodating opposing distal spine of movable finger between, each finger distally with two rows of teeth, spooned; opposable margins nearly straight; fixed finger with row of small spines along mesial margin.

P2–4: Moderately slender, with numerous long setae. P2 twice carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.7 length of P3 merus); P2 merus 0.8 carapace length, 3.5 times as long as broad, 1.2–1.5 times longer than P2 propodus; P3 merus 3.2 times longer than broad, 1.5 times longer than P3 propodus; P4 merus 3.5 times as long as broad, 1.2–1.5 length of P4 propodus. Extensor margins with row of 9–11 proximally diminishing spines on P2–3, 6 or 7 on P4; flexolateral margin distally ending in 1 spine followed proximally by 1 or 2 spines and several tubercles or eminences. Carpi with 4 or 5 spines on extensor margin on P2–4; lateral surface with 3 or 4 spines sub-paralleling extensor margin on P2–4; flexor distal margin with small distal spine. Propodi 5.0 (P2), 4.5 (P3) and 4.2 (P4) times longer than broad; extensor margin with 3 or 4 spines on proximal half on P2–4; flexor margin with 4–6 slender articulating seae. Dactyli distally ending in wellcurved strong spine, 0.5–0.6 length of propodi; flexor margin with 5 proximally diminishing teeth.

Epipods only on P1.

Remarks. Paul’son (1875) described G. longimana based on one male and one female collected from Ras Muhammad, Red Sea. Unfortunately the types are no longer extant. The present specimens collected in the Gulf of Suez agree quite well with the figure and the description provided in the original description. The number of spines on the carapace surface, as well as the length of the rostrum and P1 articles, closely fit the original description and illustrations by Paul’son. Therefore, we feel little hesitation to refer our specimens to G. longimana .

Galathea longimana resembles G. acerata n. sp. from the Western Australia (see Remarks of the latter species).

No genetic data are available for G. longimana .

Distribution. Red Sea, shallow waters (no depth recorded).

Figures

FIGURE 60. Galathea longimana Paul’son, 1875, male, 4.1 mm, Red Sea (MNHN-IU- 2013 - 14171). 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, left P 4, lateral view. Scale: A, F, G = 1 mm; E = 2 mm; B – D = 0.5 mm.