Alcomaja confragosa ( Griffin & Tranter, 1986 )

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 : 147

Alcomaja confragosa ( Griffin & Tranter, 1986)

( Figs. 16D, E , 18A, B , 19G )

Maja confragosa Griffin & Tranter, 1986: 213 , figs. 72, 73a, b, pl. 16. – Poore et al., 2008: 61. – Ng et al., 2008: 117 (list).

Material examined. Australia – 1 young female (21.5 × 18.2 mm) ( NMV J53978 ), off Point Cloates, 22°37.06’S 113°29.03’E – 22°37.02’S 113°28.56’E, Western Australia, 355–382 m, coll. G. Poore, CSIRO RV Southern Surveyor , 9 December 2005 .

Diagnosis. Carapace pyriform; dorsal surface of carapace and ambulatory legs covered with short, hooked setae; with small and large rounded granules, some of which merge basally ( Fig. 16D, E ). Pseudorostral spines with rounded cross-section ( Fig. 18A, B ). Intercalated spine acutely triangular; antorbital spine gently curved ( Fig. 18A, B ). Lateral and branchial spines strong in juveniles, weak in adults ( Fig. 16D, E ). Subhepatic region with distinctly granulated surface. Basal antennal article with numerous distinct granules. Ischium of third maxilliped distinctly granulated, especially on outer margin, with 2 large blunt distal spines. Adult male ambulatory leg condition not known ( Fig. 16E ). G1 gently curved, distal part relatively short ( Fig. 19G ).

Remarks. A small female specimen collected from the northern part of Western Australia agrees very well with the type male described in Griffin & Tranter (1986). The holotype of Maja confragosa was described from Indonesia, in the Eastern Mollucas. The new material comes from the Tropic of Capricorn near 22°S in the same depth range, around 300 m.

Differences with the allied A. irrorata n. sp. and A. gracilipes ( Chen & Ng, 1999) are discussed under these two species.

Figures

Fig. 16. General habitus, Alcomaja species. A, A. irrorata n. sp., holotype male (52.6 × 45.7 mm) (NMCR), Philippines; B, A. gracilipes, holotype male (45.4 × 43.5 mm) (IOCAS K33B-34), South China Sea; C, A. gracilipes, male (41.4 × 35.4 mm) (ZRC 2013.1225), Philippines; D, A. confragosa, female (21.5 × 18.2 mm) (NMV J53978), Australia; E, A. confragosa, holotype male (as Maja confragosa, after Griffin & Tranter 1986: pl. 16a).

Fig. 18. Frontal regions of carapace showing different structures of intercalated teeth, Alcomaja species. A, A. confragosa, holotype male (as Maja confragosa, after Griffin & Tranter, 1986: pl. 16a); B, A. confragosa, female (21.5 × 18.2 mm) (NMV J53978), Australia; C, A. gracilipes, holotype male (45.4 × 43.5 mm) (IOCAS K33B-34), South China Sea; D, A. gracilipes, male (41.4 × 35.4 mm) (ZRC 2013.1225), Philippines; E, A. irrorata n. sp., paratype male (44.7 × 39.1 mm) (ZRC 2013.1229), Philippines; F, A. irrorata n. sp., holotype male (52.6 × 45.7 mm) (NMCR), Philippines.

Fig. 19. Left G1s, Alcomaja species. A–C, A. irrorata n. sp., holotype male (52.6 × 45.7 mm) (NMCR), Philippines; D–F, A. gracilipes, holotype male (45.4 × 43.5 mm) (IOCAS K33B-34), South China Sea; G, A. confragosa (as Maja confragosa, after Griffin & Tranter, 1986: fig. 73a). Scale bars = 1.0 mm [A–C].