Galathea magnifica Haswell, 1882

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 : 182-183

Galathea magnifica Haswell, 1882

( Fig. 65 )

Galathea magnifica Haswell, 1882a: 761 (off Broughton's Islands near Port Stephens, 46 m).— Haswell, 1882b: 162 (no record).— Grant & McCulloch, 1906: 47, pl. 4, figs 3, 3a (Port Curtis and off Mast Head Island, Queensland, 13–31 m).— Balss, 1921: 23 (Cape Jaubert, North Western Australia, 20–22 m).— Hale, 1927: 79, fig. 75 (no record).— Haig, 1973: 280 (between Port Stephens and Newcastle, New South Wales and Spencer Gulf, South Australia, 29–110 m).— Haig, 1974: 446 (no record).— Davie, 2002: 62 (no record).— Poore, 2004: 232, fig. 63g, pl. 13e (compilation).—Baba et al., 2008: 73 (compilation).— Poore et al., 2011: 333, pl. 11B (color photo, eastern Australia).

Material examined. Syntypes: Australia. New South Wales. Broughton Islands, 32.62°S, 152.32°E, 46 m: 5 M 2.0– 3.3 mm, 2 ov. F 3.6–3.7 mm, 5 F 3.3–4.5 mm (AM-P271).

Australia. New South Wales. Diamond Reef, SE Hallidays Point, 32.09067°S, 152.551500°E, 18 m, 21 March 2003: 1 M 2.8 mm (AM-P75445).

Description. Carapace: 0.9 times as long as broad; dorsal surface nearly horizontal from anterior to posterior; transverse ridges with short fine setae and some scattered long plumose setae (not figured); cervical groove distinct, laterally bifurcated; gastric and anterior branchial regions only with scale-like or in concentric arcs; hepatic region with small spine near anterolateral spine; epigastric region with 2 median spines; branchial regions unarmed; mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by some interrupted transverse ridges, being scale-like on branchial regions. Lateral margins well convex medially, with 6 spines: 1 spine in front of and 5 spines behind anterior cervical groove; first anterolateral; 2 spines on anterior branchial margin, and 3 spines on posterior branchial margin; additional spine ventral to between first lateral spine and anteriormost spine of branchial margin. External limit of orbit with small spine; infraorbital margin with 1 spine. Rostrum broad triangular, 1.3 times as long as broad, length 0.5 postorbital carapace length and breadth 0.3 that of carapace, nearly horizontal in lateral view; distance between distalmost lateral incisions 0.3 distance between proximalmost lateral incisions; dorsal surface with small scale-like setiferous ridges; lateral margin with 4 deeply incised sharp teeth.

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

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

Abdomen: Somites 2–4 each with 2 transverse ridges on tergite, without additional interrupted ridges between, anterior ridge more distinctly elevated than posterior ridge; somite 5 with 2 medially interrupted ridges; tergite of somite 6 with some scale-like ridges, posteromedian margin nearly straight with setiferous ridge, all these ridges with posteriorly directed fine setae. Males with G1 and G2.

Eyes: Ocular peduncles 1.5 times longer than broad, maximum corneal diameter 0.6 rostrum width.

Antennule: Article 1 with 3 well-developed spines, distodorsal larger; distomesial spine subequal in length to but somewhat more slender than distoventral. Ultimate article without short fine setae on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine exceeding distal margin of article 2. Article 2 with 2 distal spines, distomesial spine slightly longer than distolateral, not reaching end of article 3. Article 3 with distinct distomesial spine. Article 4 unarmed.

Mxp3: ischium with well-developed distal spine on flexor margin; extensor margin with small but distinct distal spine; crista dentata with 20–24 denticles. Merus equally long as ischium; flexor margin with 2 strong subequal spines, proximal one located at midlength, distal one at terminal end; extensor margin with obsolescent distal spine. Carpus unarmed.

P1: 2.5 (females), 3.5 (male) times carapace length, relatively slender, subcylindrical, somewhat depressed on palm, more so on fingers. Merus 0.9 times length of carapace, 1.3 times as long as carpus, with spines arranged roughly in rows, distal spines prominent. Carpus 0.8 length of palm, 1.7 times as long as broad (breadth measured at midlength); dorsal surface with small spines arranged roughly in longitudinal rows; mesial margin with 3 strong spines (distal second largest). Palm 1.8 times longer than broad, lateral and mesial margins subparallel; spines arranged roughly in rows; dorsolateral row of larger spines not continued on to lateral margin of fixed finger. Fingers 0.9 length of palm, each finger distally with two rows of teeth, spooned; mesial margin of movable finger unarmed.

P2–4 (mostly detached): moderately slender, with long sparse setae. P2 merus 0.7 carapace length, 3.0 times as long as broad, 1.4 times longer than P2 propodus; flexor margin with row of 7 or 8 proximally diminishing spines; distoflexor angle ending in 2 spines. Carpus with 5 spines on extensor margin; lateral surface with 2 or 3 spines sub-paralleling extensor margin. P2–4 propodi 3 or 4 times as long as broad; extensor margin unarmed; flexor margin with 6 slender movable spines. Dactyli distally ending in well-curved strong spine, 0.8 length of propodus slightly less than that of propodi; flexor margin with 5 proximally diminishing teeth.

Epipods only on P1.

Remarks. Galathea magnifica belongs to the group of species characterized by the presence of scale-like ridges on the gastric region of the carapace, the absence of dorsal spines on the gastric region, and the possession of pereiopodal epipod only on the P1. It can be easily differentiated from other species of the group, e.g. G. bracteosa n. sp. from French Polynesia and G. ploto n. sp. New Caledonia and Chesterfield Islands, by the presence of two spines on the distal flexor angle of P2–3 meri, instead of only one spine in the latter two species.

Galathea magnifica is also close to G. poupini n. sp. (see Remarks of the latter species).

No genetic data are available for G. magnifica .

Distribution. Australia, from North Western Australia, Queensland to New South Wales and south Australia, 13– 110 m.

Figures

FIGURE 65. Galathea magnifica Haswell, 1882, syntype, female, 3.4 mm, Australia, New South Wales (P 271). A, carapace and abdomen, dorsal view; B, thoracic sternites 3, 4 and 5; C, right pterygostomian region, lateral view; D, left part of cephalothorax, ventral view, showing antennular and antennal peduncles, and anterior part of pterygostomian flap; E, ischium, merus and carpus of right Mxp 3, lateral view; F, right P 1, dorsal view; G, probably right P 2 (all P 2 - 4 detached), lateral view. Scale: A, C, F, G = 1 mm; B, D, E = 0.5 mm.