Neomaja, Ng & Forges, 2015

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 : 128

publication ID	https://doi.org/ 10.5281/zenodo.5384590
publication LSID	lsid:zoobank.org:pub:40BCDD62-D35E-46D1-95A3-2CC0DF219DEE
DOI	https://doi.org/10.5281/zenodo.5466789
persistent identifier	https://treatment.plazi.org/id/826F8B85-D147-4E7F-A9B7-857DC3CF5678
taxon LSID	lsid:zoobank.org:act:826F8B85-D147-4E7F-A9B7-857DC3CF5678
treatment provided by	Valdenar
scientific name	Neomaja
status	gen. nov.

Treatment

Neomaja View in CoL n. gen.

Diagnosis. Carapace pyriform; dorsal surface covered by granules and tubercles, spines large; gastric and branchial regions not distinctly demarcated, separated by shallow grooves; gastric and cardiac regions each with 1 distinct spine ( Fig. 6C, D View Fig ). Intestinal region with distinct median spine ( Fig. 6C, D View Fig ). Pseudorostral spines long, strongly divergent, forming a V ( Fig. 6C, D View Fig ). Supraorbital eave with anterior part longitudinally narrow, rectangular, not prominently expanded; antorbital spine sharp ( Fig. 36F View Fig ). Intercalated spine relatively short, stout, separated from supraorbital eave and postorbital spine by narrow gaps; postorbital spine very strong, long. Hepatic region with 1 strong spine, shorter than postorbital spine; 1 smaller spine below ( Fig. 36F View Fig ). Lateral carapace margin with 3 large spines, branchial region with strong spine ( Fig. 6C, D View Fig ). Posterior carapace margin with 2 median spines ( Fig. 6C, D View Fig ). Eyes relatively long, thin, slightly curved, with ovoid cornea ( Fig. 36F View Fig ). Antennal flagellum short, slender. Basal antennal article as broad as long, quadrate, with 1 long distal spine, 1 low, lobiform proximal lateral tooth; proximal outer angle rounded; inner and outer lateral margins entire; antero-external crested rim of antennular fossa prominently overlaps subdistal part of basal antennal article as hook-shaped structure by more than half its width ( Fig. 39E, F View Fig ). Epistome as long as wide, anterior margin with 2 large rounded tubercles; posterior margin composed of 4 rectangular plates separated by deep fissures ( Figs. 39E, F View Fig , 41D View Fig ). Suborbital margin separated from basal antennal article and margin of postorbital tooth by 2 distinct gaps, basally wide but with anterior parts adjoined to form fissures ( Figs. 39E, F View Fig , 41D View Fig ). Outer surface of third maxilliped covered by short setae; ischium subrectangular, distinctly longer than broad; postero-external angle of merus relatively broad, “inserted” into shallow concavity on outer margin of ischium; antero-internal part of ischium rounded, auriculiform ( Fig. 43G, H View Fig ). Male chelipeds long in adult males, surfaces of merus and carpus covered with distinct tubercles and granules; carpus elongate, with granulated longitudinal ridge; propodus of palm elongated, curved, smooth, without lateral cristae, slightly enlarged, longer than palm; fingers long, slender, gently curved, with narrow basal gape when closed ( Figs. 6C, D View Fig , 53G, H View Fig ). Ambulatory legs relatively short, thick; merus with strong, stout subdistal spine; dactylus relatively short, curved, covered with dense short setae except for corneous distal quarter ( Figs. 6C, D, F View Fig , 55D View Fig ). Thoracic sternum wide; surfaces of somites 5–8 almost smooth; sternites 3 and 4 slightly depressed; margin between sternites 2 and 3 demarcated by notch; anterior margin of sterno-abdominal cavity not forming complete rim ( Figs. 47H, I View Fig , 52C View Fig ). Male abdomen subrectangular, with 6 free somites and telson; somites 3 and 4 distinctly wider than somites 5, 6 and telson; telson semicircular ( Fig. 47H, I View Fig ). Male press-button abdominal locking mechanism submedian in position on sterno-abdominal cavity ( Fig. 52C View Fig ). Female abdomen dome-shaped, covering most of thoracic sternum. G1 very long, slender, gently curved, distal part dilated, sub-spatuliform, without subdistal process, with scattered very short setae ( Fig. 7R–T View Fig ).

Type species. Maja goltziana d’Oliviera, 1889 , by present designation.

Etymology. The genus name alludes to the new taxon being different from Maja s. str. gender feminine.

Remarks. Maia goltziana was compared to Maja spinigera De Haan, 1837 (presently in Paramaya ) by Bouvier (1940: 323, 324) who commented that in the former species, “…une forte épine au bout distal du mérus des pattes ambulatoires”. The species is also characterised by possessing relatively shorter antennae ( Fig. 39E, F View Fig ) compared to other Maja s. str. species ( Fig. 39B, C View Fig ). The differences in the form of the epistome (relatively longer) ( Figs. 39E, F View Fig , 41D View Fig ), presence of distal spines on dorsal margins of the ambulatory meri ( Fig. 6C, D, F View Fig ), and proportionately broader male abdomen ( Fig. 47H, I View Fig ) suggest it should be referred to its own genus, Neomaja . Its affinities, however, are clearly with Maja s. str., notably in the relatively broad and short basal antennal article ( Fig. 39E, F View Fig ), form of the chelipeds (including the prominent granulation on the carpus) ( Fig. 53G, H View Fig ), and general structure of the G1 ( Fig. 7R–T View Fig ). This taxonomy is consistent with the molecular study of Sotelo et al. (2009) which shows that M. squinado , M. brachydactyla , M. crispata and M. cornuta (as Maja sp. “SA”) form a distinct clade, separate but sister to M. goltziana .