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 Author Ng, Peter K. L. Author Forges, Bertrand Richer De text Raffles Bulletin of Zoology 2015 2015-05-29 63 110 225 journal article 10.5281/zenodo.5384590 2345-7600 5384590 40BCDD62-D35E-46D1-95A3-2CC0DF219DEE Sakaija n. gen. Diagnosis. Carapace pyriform to rounded in adults; dorsal surface inflated, covered by rounded granules; gastric and branchial regions delimited by grooves ( Figs. 28–30 , 31A, B, D, E , 32 ). Intestinal region with small median spine, often reduced to blunt tubercle ( Figs. 28–30 , 31A, B, D, E , 32 ). Pseudorostral spines relatively short, diverging,( Figs. 28–30 , 32 , 37K–O ). Supraorbital eave with anterior part longitudinally narrow, rectangular, not prominently expanded; antorbital spine sharp ( Fig. 37K–O ). Intercalated spine distinct, separated from supraorbital eave and postorbital spine by distinct gaps; postorbital spine strong, lobiform; hepatic region with 1 spine, shorter than postorbital spine; 1 or more smaller spines below ( Fig. 37K–O ). Lateral carapace margin with 2 short spines and numerous granules, some sharp; branchial region with 1 spine ( Figs. 28–30 , 31A, B, D, E , 32 ). Posterior carapace margin with 2 very short median spines, sometimes almost undiscernible in adults ( Figs. 28–30 , 32 ). Eyes relatively short, slender, with ovoid cornea ( Fig. 37K–O ). Antennal flagellum short, slender. Basal antennal article longer than broad, rectangular; surface granulated, with 2 spines distally; inner and outer lateral margins with low granules; proximal outer angle rounded; antero-external crested rim of antennular fossa touches but does not significantly overlap distal part of basal antennal article ( Figs. 28F , 40J–M ). Epistome slightly wider than long, anterior margin unarmed; posterior margin composed of 4 rectangular plates separated by shallow fissures ( Figs. 28F , 40J–M , 42F ). Suborbital margin separated from basal antennal article by short fissure, confluent with margin of postorbital tooth ( Fig. 40J–M ). Outer surface of third maxilliped covered by scattered setae in adults; ischium subrectangular, just longer than broad; postero-external angle of merus relatively broad, “inserted” into shallower concavity on outer margin of ischium; antero-internal part of ischium rounded, auriculiform ( Fig. 46G–L ). Male chelipeds relatively short in adult males, surfaces of merus and carpus smooth; carpus short, with low longitudinal ridge; propodus of palm smooth, short, inflated in adults, palm longer than fingers; fingers slender, gently curved, with distinct basal gape when closed ( Figs. 28–30 , 32 , 54J–M ). Ambulatory legs slender or stout, slender; merus without dorsal subdistal spine; dactylus elongate, curved, covered with long setae except for corneous tip ( Figs. 28–30 , 31C, F , 56H–J ). Thoracic sternum wide; surfaces of somites 5–8 with numerous prominent rounded tubercles and granules; sternites 3 and 4 distinctly depressed; margin between sternites 2 and 3 demarcated by deep notch; anterior margin of sterno-abdominal cavity not forming complete rim ( Figs. 51A–E , 52J ). Male abdomen subrectangular, with 6 free somites and telson; somites 3–6 and telson subequal in width ( Fig. 51A–E ). Male pressbutton abdominal locking mechanism submedian in position on sterno-abdominal cavity ( Fig. 52J ). Female abdomen dome-shaped, covering most of thoracic sternum. G1 short, slender, gently curved, distal part slightly spatuliform, tip rounded, margins lined with numerous long setae ( Fig. 33 ). Type species. Maja japonica Rathbun, 1932 , by present designation. Etymology. The genus name is derived from an arbitrary combination of the family name Sakai with Maja . It honours the significant work done by the late Tune Sakai in advancing our knowledge of Asian Majoidea. Gender feminine. Remarks. Sakaija gen. nov. is established to accommodate the following species: Sakaija japonica ( Rathbun, 1932 ) from Japan , S. sakaii ( Takeda & Miyake, 1969 ) from Japan , S. serenei n. sp. from Philippines , S. santo n. sp. from Vanuatu , S. africana ( Griffin & Tranter, 1986 ) from South Africa , and S. longispinosa n. sp. from the western coast of Australia . The primary diagnostic feature for members of this genus is the characteristic slender and sinuous or curved G1, the distal part of which is lined with numerous long setae. Members of Sakaija , however, can also be recognised by a suite of characters: a distinctly pyriform carapace that has relatively short pseudorostral spines, the suborbital margin confluent with the margin of the postorbital tooth, and shape of the male thoracic sternum and abdomen. Noteworthy is also that all the species are relatively small, the largest being about 30 mm carapace length ( S. africana ), and small species maturing at carapace lengths of only 10 mm (e.g., S. serenei ).