Galathea formosa De Man , 1902

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 : 116-119

Galathea formosa De Man, 1902

( Fig. 38 )

Galathea formosa De Man, 1902: 717 , pl. 23, figs 40, 40a–40f ( Ternate, Indonesia).— Baba, 1977a: 249 (Obi major).— Baba, 1979b: 652 (Gorong Island, subtidal).—Baba et al., 2008: 69 (compilation).

Material examined. Holotype: Indonesia, Moluccas, Ternate: ov. F 3.2 mm ( SMF 4559).

Indonesia. Gorong Island. Rumphius Expedition, 25 January 1975: 1 F 2.1–2.6 mm (MNHN-Ga1149, MNHN- IU-2013-14273).— 27 January 1975: 1 M 2.6 mm (MNHN-Ga1150, MNHN-IU-2013-14274).

Taiwan. Houbihu, Pingtung County, July 2013: 1 ov. F 4.2 mm ( NTOU).

Description. Carapace: As broad as long; transverse ridges with dense short setae, without long setae; cervical groove slightly distinct, laterally bifurcated. Gastric region with some transverse ridges: 1 epigastric ridge medially interrupted, unarmed; 1 protogastric ridge, interrupted (holotype) or uninturrupted, slightly convex medially, without parahepatic spines; 1 mesogastric ridge interrupted, not extending laterally to anteriormost of branchial marginal spines; 2 metagastric ridges, anterior ridge medially interrupted, not continuing laterally to anteriorbranchial ridges, posterior ridge scale-like. Hepatic region with small spine on each side. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 5 ridges before posterior ridge, 1 or 2 ridges uninterrupted. Lateral margins slightly convex medially, with 6 spines: 1 spine in front of and 5 spines behind anterior cervical groove; first anterolateral, well-developed, behind level of lateral limit of orbit, 1 spine ventral to between first and second spines; 2 spines on anterior branchial region, last small, and 3 spines on posterior branchial margin, last small. Front margin oblique, lateral limit of orbit with small spine; infraorbital margin with strong spine. Rostrum truncate, 0.8 times as long as broad, length 0.5 postorbital carapace length and breadth 0.4 that of carapace; distance between distalmost lateral incisions 0.2 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with numerous small scale-like setose ridges; lateral margin with 5 deeply incised teeth (4 in left margin of holotype).

Pterygostomian flap rugose, unarmed, ridges with short setae, anterior margin ending in spine.

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

Abdomen: Somite 2 with 2 uninterrupted ridges; somites 3–6 smooth, only with anterior ridge; posteromedian margin of somite 6 straight. Males with G1 and G2.

Eyes: Ocular peduncles 1.2 times longer than broad, maximum corneal diameter 0.6 rostrum width.

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

Antenna: Article 1 with ventral distomesial spine barely reaching distal margin of article 2. Article 2 with 2 small distal spines, distolateral spine slightly longer than distomesial, reaching midlength of article 3. Article 3 unarmed or with small distolateral spine. Article 4 unarmed.

Mxp3: Ischium with flexor margin ending in small spine, extensor margin ending in acute point; crista dentata with 24 or 25 denticles. Merus slightly shorter than ischium; flexor margin with 2 small subequal spines; extensor margin unarmed. Carpus unarmed.

P1: 1.9 times carapace length, with numerous scales with numerous long setae, some of them iridescent. Merus 0.8 times carapace length, 1.9 times as long as carpus, with some spines, dorsomesial and distal spines stronger than others. Carpus 0.7–0.9 length of palm, 1.8 times as long as broad; dorsal surface with some spines; mesial margin with row of strong spines. Palm 1.9 times as long as broad, lateral and mesial margins subparallel; spines arranged roughly in dorsal, dorsolateral and dorsomesial rows. Fingers slightly shorter than palm, each finger distally with two rows of teeth, spooned; fixed finger with some spines along lateral margin; movable finger with 3 proximal spines.

P2–4: moderately long and slender, with some setose striae and sparse long setae. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.8 length of P3 merus). P2 1.9 times carapace length. P2 merus 0.8 carapace length, 3.5 times as long as broad, 1.7–1.8 times longer than P2 propodus; P3 merus 3.0 times longer than broad, 1.4–1.5 times longer than P3 propodus, P4 merus 2.5–2.7 times longer than broad, 1.4 times longer than P4 propodus. Extensor margin of P2–3 meri with row of 7–9 proximally diminishing spines, 3 or 4 spines on P4; ventral margins distally ending in strong spine followed proximally by 0–1 spines or several eminences; lateral sides unarmed on P2–3, with 3 spines on P4. Carpi with 4 spines on extensor margin on P2–4; lateral surface with some spines or acute granules sub-paralleling extensor margin on P2–4; flexor distal margin ending in acute angle. P2–4 propodi 3.2 (P2), 4.0 (P3), 3.5 (P4) times as long as broad; extensor margin with 1–3 proximal spines on P2–4; flexor margin with 4 slender movable spines. Dactyli distally ending in well-curved strong spine, length 0.6–0.7 that of propodi; flexor margin with 4 or 5 proximally diminishing teeth, terminal one prominent.

Epipods on P1.

Remarks. The specimens collected from Taiwan and Gorong Island ( Indonesia) agree generally with the holotype. The protogastric ridge is interrupted in the holotype but uninterrupted in the other specimens. Galathea formosa appears closest to G. maculiabdominalis Baba, 1972 (see Remarks of the latter species). No genetic data are available for this species.

Distribution. Taiwan, Indonesia; on corals.

Figures

FIGURE 38. Galathea formosa De Man, 1902, A-E, holotype, ovigerous female, 3.2 mm, Indonesia, Moluccas (SMF 4559); F- H, ovigerous female, 4.2 mm, Philippines (NTOU). 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.