Galathea labidolepta Stimpson, 1858

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 : 153-155

Galathea labidolepta Stimpson, 1858

( Fig. 53 )

Galathea labidolepta Stimpson, 1858: 89 (Simons Bay, Cape of Good Hope, 22 m).— Stimpson, 1907: 231, Simons Bay, Cape of Good Hope, 22 m).— Doflein & Balss, 1913: 140, fig. 6 ( South Africa near East London, 80–102 m).— Lenz & Strunk, 1914: 287, fig. 1.—Baba et al., 2008: 71 (compilation).

Galathea intermedia .— Barnard, 1946: 378 (South African waters).— Barnard, 1950: 483, figs 91, a–e (Simon's Bay, Agulhas Bank, Algoa Bay, and East London, 37–77 m).— Tirmizi & Javed, 1993: 69, fig. 30 (western Indian Ocean off South Africa, 68–70 m) (not Galathea intermedia Liljeborg, 1851 ).

Material examined. South Africa. Port Elizabeth, White Island, 18–20 m, 18 February 1999: 1 M 4.2 mm (UF6885).

South Africa, Agulhas Cape, R/S Valdivia, Stn 96, 35°2'S, 19°58'E, 80 m, 27 October 1898: 1 ov. F 5.9 mm ( SMF 4570).

Description. Carapace: as long as broad; transverse ridges with dense short setae, without long setae; cervical groove distinct, laterally bifurcated. Gastric region with 8 transverse ridges: 2 epigastric ridges, anterior ridge medially interrupted, with 2 median spines, posterior ridge scale-like; 2 protogastric ridges, anterior one uninterrupted, without parahepatic spines, posterior ridge scale-like; 1 mesogastric ridge uninterrupted, not extending laterally to anteriormost of branchial marginal spines; 3 metagastric ridges, anterior ridge uninterrupted and extending laterally to anterior branchial ridges. Hepatic region unarmed or with 1 small hepatic spine in one side near first anterolateral spine (only in one specimen). Anterior branchial region with distinct ridges. Midtransverse ridge uninterrupted, preceded by shallow cervical groove, followed by 6 ridges, 4 uninterrupted. Lateral margins well convex medially, with 7 spines: 1 spine in front of and 6 spines behind anterior cervical groove; first anterolateral, well-developed, slightly posterior to level of lateral limit of orbit, without spine ventral to between first and anteriormost spine of branchial margin; 3 spines on anterior branchial region, and 3 spines on posterior branchial margin, last small. Small spine on lateral limit of orbit, with 1 small frontal spine; infraorbital margin with 2 spines. Rostrum 1.9 as long as broad, length 0.6 postorbital carapace length and breadth 0.3 that of carapace; distance between distalmost lateral incisions 0.4 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with some setose scales; lateral margin with 4 deeply incised sharp teeth.

Pterygostomian flap rugose, with 7 or 8 distinct spines on upper margin near linea anomurica, ridges with short setae, anterior margin blunt.

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 each with 2 medially interrupted ridges; posteromedian margin of somite 6 slightly convex. Males with G1 and G2.

Eyes: Ocular peduncles 1.5 times longer than broad, maximum corneal diameter 0.7 rostrum width.

Antennule: Article 1 with 2 well-developed distal spines, distodorsal larger, distomesial spine obsolescent. Ultimate article with a few short fine setae not in tuft on distodorsal margin.

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

Mxp3: Merus more than twice ischium length, with 1 or 2 small spines on flexor distal margin, 1 distal spine on extensor margin; crista dentata with 17–20 denticles. Merus with flexor margin with 2 subequal spines in distal half; extensor margin with 1 small distal spine, and 0–3 small spines along extensor border. Carpus unarmed; propodus elongate.

P1: 2.7 times carapace length, covered with finely setiferous scales, with scattered long setae; setae noniridescent. Merus 0.9 times carapace length, 1.4 times as long as carpus, with spines arranged roughly in rows, dorsomesial spines stronger; distal spines prominent. Carpus 0.8 length of palm, 1.9 times as long as broad; dorsal and lateral surfaces with some spines; mesial margin with 3 or 4 spines (distal second strong). Palm 2.2 times longer than broad, lateral and mesial margins slightly convex; spines arranged roughly in dorsolateral and dorsomesial rows, some small spines scattered on dorsal side, dorsolateral row continuing along fixed finger. Fingers slightly shorter than palm, distally not spooned; movable finger unarmed.

P2–4: moderately slender, with setose striae and sparse long setae; setae non-iridescent. P2 1.8 times carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P3 merus, P4 merus 0.9 length of P3 merus); P2 merus 0.7 carapace length, 3.4 times as long as broad, 1.4 times longer than P2 propodus. Extensor margin with row of 8–12 proximally diminishing spines on P2–3, only distal spine on P4; ventral margins distally ending in strong spine followed proximally by 0–1 spines and several eminences, lateral sides unarmed. Carpi with 6 or 7 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 3.5–4.0 times as long as broad; extensor margin with 3 or 4 proximal spines on P2–3, unarmed on P4; flexor margin with 5 slender movable spines. Dactyli distally ending in well-curved strong spine, length 0.6 that of propodi; flexor margin with 4 or 5 proximally diminishing teeth, terminal one prominent.

Epipods on P1.

Remarks. Galathea labidolepta was described by Stimpson (1858) on the basis of specimens collected from the Cape of Good Hope, South Africa. Later, Doflein & Balss (1913), and Lenz & Strunk (1914) illustrated the species after some specimens collected from the South African coast. Galathea labidolepta is characteristic by the presence of a row of spines along the upper margin of the pterygostomian flap adjacent to the linea anomurica. Furthermore, the Mxp3 merus is more than twice as long as the ischium. These characters are not observed in other species known from the Pacific and Indian Oceans, while being closer to G. intermedia Liljeborg, 1851 from the Eastern Atlantic ( Norway to Angola). The taxonomy of this species, together with other European species of Galathea is now under revision. Therefore, further studies on this species and other closely related taxa, e.g. G. bolivari Zariquiey-Alvarez, 1950 , G. cenarroi Zariquiey-Alvarez, 1968 , and G. labidolepta , are needed in order to establish the specific identities (see also Udekem D’Acoz 1999).

No genetic data are available for G. labidolepta .

Distribution. South Africa, from Cape of Good Hope to Port Elizabeth and East London, 18– 102 m.

Figures

FIGURE 53. Galathea labidolepta Stimpson, 1858, A-C, E-H, male, 4.2 mm, South Africa (UF 6885); D, ovigerous female 5.9 mm, South Africa (SMF 4570). 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, left 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, F – H = 1 mm; E = 2 mm; B – D = 0.5 mm.