Alcomaja gracilipes ( Chen & Ng, 1999 )

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 gracilipes ( Chen & Ng, 1999)

( Figs. 16B, C , 18C, D , 19D–F , 39M , 45B, C , 49B, C , 53N )

Maja gracilipes Chen & Ng, 1999: 754 , figs. 1, 2. – Yang et al., 2008: 780. – Ng et al., 2008: 117 (list).

Material examined. Holotype: male (45.4 × 43.5 mm) ( IOCAS K33 B-34), station 6080, 180 m, on gravel, South China Sea, coll. 21 April 1959. Philippines – 1 female (39.8 × 29.2 mm) (MNHN-IU-2013-4049), station CP 27, 14°00’N 120°19’E, 188–192 m, coll. RV. Vauban, MUSORSTOM 1, 22 March 1976. — 1 male (31.9 × 25.5 mm) (MNHN- IU-2013-4054), station CP 35, 13°59’N 120°18’E, 186–187 m, coll. RV Vauban, MUSORSTOM 1, 23 March 1976. — 1 male (24.8 × 19.4 mm), 1 female (16.3 × 13.2 mm) (MNHN-IU-2013-4048), station CP 61, 184– 202 m, 14°02’N 120°18’E, RV Vauban, MUSORSTOM 1, 27 March 1976. – 1 female (32.7 × 27.1 mm) (MNHN-IU-2013-4058), station CP 88, 14°00’N 120°17’E, 183–187 m, coll. RV Coriolis, MUSORSTOM 3, 31 May 1985. — 1 female (35.7 × 29.8 mm) (MNHN-IU-2013-4056), station CP96, 14°00’N 120°17’E, 190–194 m, RV Coriolis, MUSORSTOM 3, 1 June 1985. — 1 male (31.7 × 26.6 mm) (MNHN-IU-2013-4057), station CP 98, 14°00’N 120°18’E, 194–205 m, coll. RV Coriolis, MUSORSTOM 3, 1 June 1985. — 1 male (31.7 × 26.6 mm) ( ZRC 2001.432 ), Balicasag Island, Panglao, Bohol, coll. fishermen with tangle nets, December 2000. — 1 male (41.4 × 35.4 mm) ( ZRC 2013.1225 ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, June 2002. — 1 young female (24.1 × 20.5 mm) ( ZRC 2013.1224 ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, June 2002. — 1 female (32.1 × 27.5 mm) ( ZRC 2013.1227 ), Balicasag Island , Panglao, Bohol, coll. fishermen with tangle nets, 2003. — 1 female ( ZRC 2013.1228 ), Balicasag Island , Panglao, Bohol, 200–300 m, coll. fishermen with tangle nets, May 2004. — 1 male (NSMT-Cr 22327), Balicasag Island , Panglao, Bohol, coll. local fisherman via M. Takeda & H. Komatsu, February 2003. — 1 female (NSMT-Cr 22326), Balicasag Island , Panglao, Bohol, coll. local fisherman via M. Takeda & H. Komatsu, February 2003. — 1 male (41.9 × 35.2 mm) ( ZRC 2013.1226 ), northwest Panglao, Bohol, coll. J. Arbasto with tangle nets, 2006.

Diagnosis. Carapace pyriform; dorsal surface of carapace and ambulatory legs covered with short, hooked setae; with distinct small and large sharp and rounded granules ( Figs. 16B, C , 18C, D ). Pseudorostral spines with rounded cross-section ( Fig. 18C, D ). Intercalated spine subtruncate basally; antorbital spine gently curved ( Fig. 18C, D ). Lateral and branchial spines strong in juveniles, weak in adults. Subhepatic region with strongly granulated surface ( Fig. 39M ). Basal antennal article with numerous distinct granules ( Fig. 39M ). Ischium of third maxilliped distinctly granulated on surface, with 2 distinct distal spines ( Fig. 45B, C ). Adult male ambulatory legs long, especially merus and propodus first leg which can be twice length of carapace; surfaces almost smooth or with sparse setae ( Figs. 16B, C ). G1 gently curved, distal part straight ( Fig. 19D–F ).

Remarks. The specimens from the Philippines agree well with the holotype of A. gracilipes ( Chen & Ng, 1999) described from the South China Sea. The characters outlined in Chen & Ng (1999) serve to easily distinguish A. gracilipes from A. confragosa and A. irrorata n. sp. (see also discussion of A. irrorata ).

That both A. irrorata and A. gracilipes occur in the Philippines (with some specimens sympatric) does pose problems but we know too little about the ecology of these species to speculate further. In the steep slopes along Balicasag, Philippines, the dominant species is clearly A. irrorata , with only a few specimens of A. gracilipes obtained. On the other hand, only A. gracilipes was observed in the trawled material from the French expeditions to the Philippines, albeit there were only a few specimens. The type male was also collected by trawling in the South China Sea. Only one specimen of A. irrorata from off Pamilacan Island (male 43.0 × 37.2 mm, ZRC 2013.1223,) was collected by trawling in the Philippines. Whether this suggests they have different habitat preferences is not known.

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].

Fig. 39. Antennae, antennules and epistomes. A, Maja squinado, neotype male (147.1 × 126.3 mm) (SMF-4548), Croatia; B, Maja brachydactyla, male (98.4 × 89.0 mm) (ZRC 2009.1130), U.K.; C, Maja cornuta, male (115.3 × 103.4 mm) (ZRC 2013.1184), South Africa; D, Maja crispata, male (63.1 × 51.9 mm) (MNHN-IU-2013-4042), Italy; E, Neomaja goltziana, male (73.4 × 65.0 mm) (MNHN- IU-2013-4046), Congo; F, Neomaja goltziana, male (90.2 × 83.1 mm) (MNHN-IU-2013-4044), Gabon; G, Paramaja kominatoensis, dried male (62.6 × 56.1 mm) (KPM NH0104298), Japan; H, Paramaja kominatoensis, dried male (73.0 × 66.0 mm) (PCM), Taiwan; I, Paramaja gibba, lectotype female (25.1 × 21.2 mm) (NHM 1896.5.14.9), India; J, Paramaja gibba, male (79.5 × 77.9 mm) (ZRC 2013.1232), Bay of Bengal; K, Paramaja turgida n. sp., holotype male (74.1 × 66.8 mm) (NMCR), Philippines; L, Alcomaja irrorata n. sp., holotype male (52.6 × 45.7 mm) (NMCR), Philippines; M, Alcomaja gracilipes, male (41.4 × 35.4 mm) (ZRC 2013.1225), Philippines; N, Alcomaja desmondi n. sp., holotype male (35.4 × 28.3 mm) (NMCR), Philippines; O, Alcomaja nagashimaensis, male (30.5 × 26.0 mm) (ZRC 2001.430), Philippines.

Fig. 45. Third maxillipeds. A, Alcomaja irrorata n. sp., holotype male (52.6 × 45.7 mm) (NMCR), Philippines; B, Alcomaja gracilipes, holotype male (45.4 × 43.5 mm) (IOCAS K33B-34), South China Sea [third max laterally inverted to match]; C, Alcomaja gracilipes, male (41.4 × 35.4 mm) (ZRC 2013.1225), Philippines; D, Alcomaja desmondi n. sp., holotype male (35.4 × 28.3 mm) (NMCR), Philippines; E, Alcomaja nagashimaensis, holotype male (34.0 × 28.5 mm) (USNM 125886), Japan; F, Alcomaja nagashimaensis, male (30.5 × 26.0 mm) (ZRC 2001.430), Philippines; G, Alcomaja latens n. sp., holotype male (25.3 × 21.4 mm) (MNHN-IU-2013-4050), Solomon Islands; H, Alcomaja miriky n. sp., holotype male (26.4 × 20.9 mm) (MNHN-IU-2010-929), Madagascar; I, Paramaya spinigera, male (85.0 × 66.4 mm) (ZRC 1999.738), Taiwan; J, Paramaya ouch n. sp., holotype male (76.8 × 60.0 mm) (NMCR), Philippines; K, Paramaya ouch n. sp., paratype male (39.7 × 29.6 mm) (ZRC 2011.0045), Philippines; L, Paramaya coccinea n. sp., holotype male (69.0 × 55.6 mm) (MNHN), Vanuatu.

Fig. 49. Male anterior thoracic sternums and abdomens, 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. nagashimaensis, male (30.5 × 26.0 mm) (ZRC 2001.430), Philippines; E, A. nagashimaensis, male (37.2 × 32.4 mm) (CBM-ZC9928), Japan; F, A. latens n. sp., holotype male (25.3 × 21.4 mm) (MNHN-IU-2013-4050), Solomon Islands; G, A. miriky n. sp., holotype male (26.4 × 20.9 mm) (MNHN-IU-2010-929), Madagascar; H, A. desmondi n. sp., holotype male (35.4 × 28.3 mm) (NMCR), Philippines.

Fig. 53. Chelae. A, Maja squinado, neotype male (147.1 × 126.3 mm) (SMF-4548), Croatia; B, Maja brachydactyla, male (98.4 × 89.0 mm) (ZRC 2009.1130), U.K.; C, Maja brachydactyla, male (161.2 × 140.1 mm), (ZRC 2008.0179), Spain; D, Maja cornuta, male (88.8 × 86.8 mm) (NHM 1928.12.1.177–) (lectotype of Mamaia queketti Stebbing, 1908), South Africa; E, Maja cornuta, male (115.3 × 103.4 mm) (ZRC 2013.1184), South Africa; F, Maja crispata, male (63.1 × 51.9 mm) (MNHN-IU-2013-4042), Italy; G, Neomaja goltziana, male (73.4 × 65.0 mm) (MNHN-IU-2013-4046), Congo; H, Neomaja goltziana, male (90.2 × 83.1 mm) (MNHN-IU-2013-4044), Gabon; I, Paramaja kominatoensis, dried male (62.6 × 56.1 mm) (KPM NH0104298), Japan; J, Paramaja kominatoensis, dried male (73.0 × 66.0 mm) (PCM), Taiwan; K, Paramaja gibba, male (79.5 × 77.9 mm) (ZRC 2013.1232), Bay of Bengal; L, Paramaja turgida n. sp., holotype male (74.1 × 66.8 mm) (NMCR), Philippines; M, Alcomaja irrorata n. sp., holotype male (52.6 × 45.7 mm) (NMCR), Philippines; N, Alcomaja gracilipes, male (41.4 × 35.4 mm) (ZRC 2013.1225), Philippines; O, Alcomaja desmondi n. sp., holotype male (35.4 × 28.3 mm) (NMCR), Philippines; P, Alcomaja nagashimaensis, male (30.5 × 26.0 mm) (ZRC 2001.430), Philippines.