Urashima lamellidentata (Wood-Mason, 1892)

Kumar, Biju A., Kumar, M. Sushil & Galil, Bella S., 2013, Calappid and leucosiid crabs (Crustacea: Decapoda: Brachyura) from Kerala, India, with the description of a new species of Mursia Desmarest, 1823, from the Arabian Sea and redescription of M. bicristimana Alcock & Anderson, 1894, Zootaxa 3746 (4), pp. 529-551 : 548

Urashima lamellidentata (Wood-Mason, 1892)

( Figs 7 e, 12a, b, 13a–d)

Randallia lamellidentata Wood-Mason, 1892 : pl. 5, figs 5, 5a, 5b.—Alcock 1894: 404; 1896: 195; 1899: 26.—Kemp & Sewell 1912: 29.

Urashima lamellidentata —Galil 2003: 417, fig. 2e.

Kerala material examined. Neendakara, 08˚56'N 76˚32'E, 31 Aug. 2007, 1 ♂ (CW 38.1 mm) (DABFUK).

Additional material examined. Holotype, RIMS Investigator , stn 115, Andaman Is. 11˚31'40"N 92˚46'6"E, 9 Dec 1890, 188–200 fms (328–360 m), pre-adult (CW 13 mm) (NHM 1896.9.8.7 ex. Indian Museum).

Redescription (adult male). Carapace rounded, globose. Dorsal surface of carapace granular, tuberculate, tubercles more pronounced posteriorly ( Fig. 12 b). Hepatic, branchial regions demarcated by pitted grooves. Intestinal region swollen, demarcated by grooves, surfaced with rounded granules, medially with granular ridge, posteriorly with up-curved tubercle. Posterior margin of carapace narrow, bilobate. Anterolateral margin of carapace with 3 lamelliform crests separated by rounded granules; posterolateral margin set with rounded granules. Posterior margin with lateral lobes dorsoventrally flattened. Ventral surface of carapace, thoracic sterna, abdominal terga, external maxillipeds granular. Front narrow, bilobed; rounded frontal lobes closely, minutely granular. Eyes relatively small, retractable. Outer orbital margin with 3 sutures, V-shaped gap proximally on ventral margin. Antennules obliquely folded, operculiform basal antennular segment sealing posterior half of antennular aperture. Antennae proportionally small, slender, distal antennal segment inserted in orbital hiatus. Postorbital region concave. Anterior margin of efferent branchial channel produced, bilobed, separated from lower orbital margin by narrow groove. Pterysostomian region with large rounded tubercles. Third maxilliped unevenly granular; exopod shorter than endopod, not sealing efferent branchial channel; endopod merus subtriangular, shorter than subrectangular ischium, with rounded granules medially. Chelipeds subequal, stout, with conic granules. Cheliped merus subcylindrical; upper, lower margins of palm prominently crested; fingers laterally compressed, as long as upper margin of palm, inner margins denticular. Pereopods slender, short, with prominent conical granules; all but fifth dactyl as long as propodi; setose, tips corneous. Fourth thoracic sternite laterally swollen. Abdominal sulcus deep, nearly reaching buccal cavity, anterior margin raised. Abdominal somites 3–6 fused, basio-lateral regions inflated, fused somite narrowing distally, with long spur-like spike at distal margin; lateral margin carinate, carina fitting into groove at suture between sternites 4, 5. Telson slender, nearly half as long as fused somite, not reaching tip of abdominal sulcus. First gonopod elongated, stout, sinuous, distally flattened, oar-like, with a densely setose lobe ( Fig. 13 a ‾ d); second gonopod short, recurved, distally scoop-like ( Fig. 7 e).

Remarks. The adult male retrieved from trawl by-catch at Neendakara fishing port is the largest specimen collected. Comparison with the pre-adult holotype (NHM 1896.9.8.7 ex. Indian Museum) reveals some differences. The tuberculation on the dorsal surface of carapace, chelipeds, pereiopods and the abdominal spine are more prominent in the adult specimen, whereas in the pre-adult the intestinal tubercle is proportionally larger ( Fig. 12 a).

Urashima lamellidentata is rarely collected, a handful of mostly pre-adults have been collected in over 120 years.

Distribution. Travancore coast, India (Wood-Mason 1892; Kemp & Sewell 1912). Bay of Bengal, Andaman Is.

Figures

FIGURE 7. Right male second gonopod, Mursia bicristimana Alcock & Anderson, 1894, Neendakara, India, 5 June 2007, ♂, CW 91.5 mm, a. entire view; b. distal end; M. arabica n. sp., Holotype. Gulf of Aden, John Murray Expedition, ♂, CW 59.3 mm, stn 35, 13 ° 14 ' 24 " N 46 ° 14 ' 12 " E, 16 Nov. 1933, c. entire view; d. distal end; Urashima lamellidentata (Wood-Mason, 1892), Neendakara, 08 ˚ 56 ' N 76 ˚ 32 ' E, 31 Aug. 2007, ♂, CW 38.1 mm, e. entire view.

FIGURE 12. Urashima lamellidentata (Wood-Mason, 1892), a. Holotype, juvenile, stn 115, Andaman Is., 11 ˚ 31 ' 40 " N 92 ˚ 46 ' 6 " E, 9 Dec. 1890, (CW 13 mm), NHM 1896.9. 8.7 ex. Indian Museum, coll. RIMS Investigator; b. Neendakara, India, 08 ˚ 56 ' N 76 ˚ 32 ' E, 31 Aug. 2007, ♂, CW 38.1 mm. Photo by Phil Hurst, NHM Photo Unit.

FIGURE 13. Urashima lamellidentata (Wood-Mason, 1892), Neendakara, India, 08 ˚ 56 ' N 76 ˚ 32 ' E, 31 Aug. 2007, ♂, CW 38.1 mm, right first gonopod; a, b. ventral view; c, d. dorsal view.