Galacantha subrostrata, Published, 2007

Published, First, 2007, Species of the genus Munidopsis Whiteaves, 1784 from the Indian and Pacific Oceans and reestablishment of the genus Galacantha A. Milne-Edwards, 1880 (Crustacea, Decapoda, Galatheidae), Zootaxa 1417, pp. 1-135 : 20-23

Galacantha subrostrata n. sp.

( Figs. 9, 10A–H)

Material examined. Central Atlantic, WALDA, Stn CY 21, 3034 m: 1 ovig. F 20.4 mm, 2 F 19.1–21.8 mm (MNHN-Ga5487).—Stn CY 22, Pt. 154, 3244 m: 8 M 7.9–18.2 mm, 3 ovig. F 17.4–20.4 mm, 2 F 8.8–12.8 mm (MNHN-Ga5479). NE Atlantic, EUMELI 2, Stn CP01, 3086 m: 4 M 9.5–20.0 mm, 2 ovig. F 21.8–23.2 mm (MNHN-Ga5478).—Stn CPH02, 3134 m: 1 F 16.0 mm ( ICM).—Stn CP03, 2114 m: 2 ovig. F 19.0– 19.8 mm, 2 F 12.2–14.0 mm (MNHN-Ga5480). EUMELI 4, Stn CPH15, 3124 m: 1 M 17.8 mm (MNHN-Ga5481). DISCOVERY, Stn 8521-1, 3053– 3058 m: 1 M 13.5 mm, 1 F 15.7 mm (MNHN-Ga5482).—Stn 8974-6, 3029– 3035 m: 1 M 16.8 mm, 1 ovig. F 21.2 mm (MNHN-Ga5483).—Stn 9132-5, 3089– 3109 m: 1 M 19.5 mm (MNHN-Ga5484).—Stn 9132-7, 3083– 3094 m: 2 M 15.1–17.4 mm, 1 ovig. F 21.2 mm (MNHN-Ga5485).— Stn 9133-7, 2130– 2191 m: 1 M 20.2 mm (MNHN-Ga5486).

Types. The male of 16.6 mm from WALDA, Stn CY22 is the holotype (MNHN Ga 5488) . The other specimens are paratypes.

Etymology. The name subrostrata refers to its relationship with G. rostrata .

Description. Carapace slightly longer than broad, covered with scale-like or spine-like tubercles, dorsally armed with 2 small epigastric, one extremely strong laterally compressed mesogastric, and one moderately large cardiac spine. Gastric and cardiac regions somewhat inflated. Lateral margins slightly convex, with 2 prominent anterior spines or acute processes, and lobe-like process at midlength, first spine well-developed and directed forward, second spine or acute process smaller than first spine (of similar size in a few specimens). Front margins oblique, without antennal spine. Posterior margin of carapace smooth. Rostrum with 2 small spines at anterior end of horizontal portion, not discernible in dorsal view; several additional granules near each spine; rostral spine slightly smaller than mesogastric spine upturned distally, forming angle of ca. 50º with horizontal portion; width of rostrum (measured at level of end of corneae) narrower than corneae; horizontal portion reaching or slightly overreaching antennal peduncle.

Sternites smooth. Sternite 3 bilobate, separated by notch, about one-third width of sternite 4; each lobe with lateral margin rounded; ridges demarcating sternites 4–7 feebly granular. Sternite 4 truncate subtriangular, relatively narrow anteriorly.

Abdominal 2–4 tergites with 2 moderately elevated transverse ridges, each anterior ridge with prominent median spine, spine on tergite 4 clearly smaller than preceding spines; tergite 4 with transverse groove between ridges interrupted medially; tergite 5 smooth with a few small granules. Pleura of segments 2–3 with numerous granules, less numerous granules on segment 4. Tergite 6 having slightly convex posterior margin, not overreaching posterolateral lobes. Telson divided into 10 plates, midlateral plates with stiff setae in male; posterior plates combined nearly twice as wide as long.

Eye movable and spineless, corneae subglobular. Basal article of antennule with small distomesial, strong distolateral, and small dorsolateral spines, last one occasionally absent; distal mesio-ventral margin with broad, thin, distally dentate process. Antennal peduncle spineless.

Mxp 3 merus with 2 or 3 spines on flexor margin, proximal spine largest, extensor margin unarmed; mesial ridge of ischium bearing 12–15 denticles.

P1 covered with tubercles and granules, 1.6–1.8 (males), 1.4–1.5 (females) times carapace length, nearly spineless; merus and carpus each with several terminal spines, carpus as long as palm, 1.5 times longer than wide; palm 1.5 times longer than wide, fingers distinctly longer than palm, distally spooned, prehensile edges crenulate.

P2–P4 long, slender, with numerous granules, subcylindrical. P2 overreaching P1, twice carapace length. P2 merus 3.5 times length of carpus, 1.5 times longer than propodus and nearly 6 times longer than high, slightly longer than that of P3 and 1.2 times that of P4, slightly overreaching rostrum, having distal spine on dorsal and ventral margin; carpus having dorsolateral granulated crest; propodus 5.5 times longer than high, nearly 1.5 times dactylus length, ventral margin unarmed; dactylus compressed laterally, flexor border moder- ately curving, bearing 12–17 proximally diminishing low teeth, ultimate tooth rather remote from end of dactylus and much closer to penultimate; distal half of extensor margin with numerous uniramous setae.

Remarks. Galacantha subrostrata belongs to the group of species with the rostrum having two small and subparallel spines at the end of the horizontal portion, not visible dorsally, the carapace with second lateral (hepatic) spine shorter than first (anterolateral) spine, the fourth abdominal tergite with transverse groove between ridges interrupted medially, and the pleura of second and third abdominal tergites with a few granules. Galacantha subrostrata is closest to G. bellis Henderson, 1885 (see above), differentiated by the following:

— The first lateral (anterolateral) spine longer (or subequal in a few specimens) than the second lateral (hepatic) spine in G. subrostrata , whereas the second spine is always larger than the first (anterolateral) spine in G. bellis .

— The epigastric spines are smaller in G. subrostrata than in G. bellis .

— The transverse groove of the fourth tergite is medially interrupted in G. subrostrata , whereas this groove is not interrupted in G. bellis .

Distribution. East Atlantic, off northwest Africa to the Gulf of Guinea, at 2114–3234 m.