Alcomaja nagashimaensis (T. Sakai, 1969 )

Ng, Peter K. L. & Forges, Bertrand Richer De, 2015, Revision of the spider crab genus Maja Lamarck, 1801 (Crustacea: Brachyura: Majoidea: Majidae), with descriptions of seven new genera and 17 new species from the Atlantic and Indo-West Pacific, Raffles Bulletin of Zoology 63, pp. 110-225 : 148-152

publication ID	https://doi.org/ 10.5281/zenodo.5384590
publication LSID	lsid:zoobank.org:pub:40BCDD62-D35E-46D1-95A3-2CC0DF219DEE
persistent identifier	https://treatment.plazi.org/id/03A9654B-FFA7-0772-57D8-FE1E7865FA2A
treatment provided by	Valdenar
scientific name	Alcomaja nagashimaensis (T. Sakai, 1969 )
status

Treatment

Alcomaja nagashimaensis (T. Sakai, 1969) View in CoL

( Figs. 17A–C View Fig , 20A–J View Fig , 36M View Fig , 39O View Fig , 41H View Fig , 45E, F View Fig , 49D, E View Fig , 52G View Fig , 53P View Fig , 55N View Fig , 69A View Fig )

Maja nagashimaensis T. Sakai, 1969: 256 View in CoL , pl. 1, fig. 2, text-fig. 5b, b’. – Serène & Lohavanijaya, 1973: 50 (key). – T. Sakai, 1976: 241, pl. 85, fig. 1, text-fig. 129. – Serène & Vadon, 1981: 129. – Griffin & Tranter, 1986: 217. – Muraoka, 1998: 27. – Ng et al., 2008: 117 (list).

Maja nagasimaensis [sic] – Maramura & Kosaka, 2003: 34.

Material examined. Holotype: male (34.0 × 28.5 mm) ( USNM 125886 View Materials ), on rocky shore, Kii Nagashima, Mie Prefecture, Honshu Island , Japan , coll. Y. Yamamoto. Others: Japan – 1 male (37.2 × 32.4 mm) ( CBM-ZC9928 ), Ohse-Zaki , Suruga Bay , 35°3.53’N 138°48.26’E, 135–142 m, in 1 m ORI dredge, cruise KT04-6, station OS-1, coll. T. Akiyama, RV Tansei-Maru, 4 May 2004. Philippines – 2 males (27.3 × 23.3 mm, 28.7 × 23.9 mm), 1 ovigerous female (23.9 × 20.6 mm) ( ZRC 2013.1393 View Materials , ex part ZRC 2001.0435 View Materials ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, December 2000. — 2 ovigerous females (24.7 × 20.6 mm, 24.6 × 22.3 mm), 3 males (23.4 × 19.5 mm, 21.9 × 18.4 mm, 15.7 × 7.3 mm) ( ZRC 2001.0434 View Materials ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, December 2000. — 1 male (30.5 × 26 mm) ( ZRC 2013.1394 View Materials , ex part ZRC 2001.430 View Materials ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, 28 November 2000. — 4 males (27.7 × 22.8 mm, 26.8 × 22.1 mm, 22.3 × 17.7 mm, 22.9 × 17.6 mm [with bopyrid], 7 ovigerous females (28.2 × 24.0 mm, 25.1× 20.8 mm, 22.9 × 18.7 mm, 25.1 × 21.1 mm, 23.1 × 20.0 mm, 22.6 × 19.1 mm) ( ZRC 2001.0585 View Materials a), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, 28 November 2001. — 1 female ( ZRC 2013.1389 View Materials , ex part ZRC 2001.0601 View Materials ), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, 28 November 2001. — 1 juvenile male ( ZRC 2013.1315 View Materials ), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, June 2002. — 2 males, 2 females ( ZRC 2013.1402 View Materials ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, June 2002. — 2 males (NSMT-Cr 15390a), Balicasag Island , Panglao, Bohol, coll. local fisherman via M. Takeda & H. Komatsu, February 2003. — 3 males (NSMT-Cr 13032), Balicasag Island , Panglao, Bohol, coll. local fisherman via M. Takeda & H. Komatsu, February 2003. — 1 male (20.8 × 16.8 mm), 3 females (23.7 × 19.4 mm, 23.2 × 19.3 mm, 23.1 × 18.2 mm), 1 ovigerous female (23.9 × 19.9 mm) ( ZRC 2013.1400 View Materials ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, July 2003. — 1 male (19.9 × 16.6 mm) ( ZRC 2013.1391 View Materials ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, July 2003. — 1 male ( ZRC 2013.1387 View Materials ), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, 25–30 July 2003. — 1 male, 1 female ( ZRC 2013.1392 View Materials ), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, November 2003. — 1 female ( AM), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, December 2003. — 3 males (22.6 × 18.7 mm, 26.4 × 21.6 mm, 28.3 × 24.1 mm) ( ZRC 2013.1381 View Materials ), 19 May 2004. — 1 male (28.9 × 24.8 mm) ( ZRC 2013.1388 View Materials ), 28 May 2004. — 1 ovigerous female ( ZRC 2013.1386 View Materials ), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, May 2004. — 1 male ( ZRC 2013.1382 View Materials ), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, 29 May 2004. — 1 male ( AM), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, 4 June 2004. — 1 male (26.1 × 22.0 mm) ( ZRC 2013.1390 View Materials ), northwest Panglao, Bohol, 120–160 m, tangle nets, coll. J. Arbasto, 1 December 2007. — 1 male (27.7 × 23.8 mm), 1 ovigerous female (20.9 × 17.4 mm), 1 female (22.2 × 19.2 mm) ( ZRC 2013.1399 View Materials ), northwest Panglao, Bohol, 120–160 m, tangle nets, coll. J. Arbasto, 2007. — 1 female (15.0 × 11.2 mm) (MNHN-IU-2013-4053), station CP 31, 14°00’N 120°16’E, 187–195 m, coll. RV Vauban, MUSORSTOM 1, 22 March 1976. — 1 ovigerous female (15.8 × 12.7 mm), 1 female (12.1 × 9.1 mm) (MNHN- IU-2013-4052) CP57, 13°53’N- 120°13’E, 96–107 m, coll. RV Vauban, MUSORSTOM 1, 26 March 1976. Taiwan – 1 male (29.5 × 24.2 mm) ( ZRC 2013.1385 View Materials ), Tashi fishing port, Ilan Province , sandy mud, 20 m, coll. Hwang 28 April 1989. — 1 male (23.2 × 18.4 mm) ( ZRC 2013.1383 View Materials ), Tashi fishing port, Ilan Province , sandy mud, 20 m, coll. Hwang, 4 July 2011. GoogleMaps

Diagnosis. Carapace pyriform; dorsal surface of carapace and ambulatory legs covered with short, hooked setae; with small rounded granules ( Fig. 17A–C View Fig ). Pseudorostral spines with rounded cross-section ( Fig. 36M View Fig ). Antorbital spine almost straight; intercalated spine acutely triangular, shorter than supraorbital and postorbital spines, with large open gaps between them; postorbital spine large, longer than others; 1 distinct hepatic spine with small basal spine ( Fig. 36M View Fig ). Lateral and branchial spines strong in juveniles and adults ( Fig. 17A–C View Fig ). Subhepatic region with rugose and weakly granulated surface ( Fig. 39O View Fig ). Basal antennal article with low granules and 2 tubercles, with 2 distal spines ( Fig. 39O View Fig , 41H View Fig ). Ischium of third maxilliped almost smooth to slightly rugose ( Fig. 45E, F View Fig ). Ambulatory legs relatively short, first leg never twice length of carapace; surfaces distinctly setose ( Figs. 17A–C View Fig , 55N View Fig ). G1 strongly curved, with distal part gently curved downwards ( Fig. 20A–J View Fig ).

Remarks. The type male ( Fig. 17A View Fig ) is very delicate and in poor condition, and appears to have dried up at some stage. The gonopods are still present, although not in a good state. The lateral and branchial spines of the type are relatively stouter ( Fig. 17A View Fig ) compared to the other specimens we have examined from Japan, Taiwan and Philippines ( Fig. 17B, C View Fig ), but this is probably due to variation. The G1 drawn by T. Sakai (1969: text-fig. 5b) (present Fig. 20A, B View Fig ) appears to have been drawn in situ and the curvature is therefore less strong compared to that when drawn ex-situ ( Fig. 20C, D View Fig ). The subdistal process observed seems to have dried up previously and looks folded, unlike the original condition figured (T. Sakai, 1969: text-fig. 5b’) which is more similar to that in the fresh material on hand. In any case, the shape and structure ( Fig. 20C, D View Fig ) agrees well with the G1s from Philippines and Taiwan and we have no doubt they are conspecific.

The chelae are only enlarged in larger males. Smaller males about 20 mm or less in carapace length (e.g., ZRC 2013.1391) have slender chelae.

Maja nagashimaensis was described from Japan, with Serène & Vadon (1981) reporting this species from the Philippines, and Griffin & Tranter (1986) recording it from the Sulu Islands in the Philippines. It is now also recorded from Taiwan.