Neomaja Ng & Forges 2015, n. gen.
Creators: name: Ng, Peter K. L.
name: Forges, Bertrand Richer De
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Majidae
Neomaja

description: Neomaja 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). Intestinal region with distinct median spine (Fig. 6C, D). Pseudorostral spines long, strongly divergent, forming a V (Fig. 6C, D). Supraorbital eave with anterior part longitudinally narrow, rectangular, not prominently expanded; antorbital spine sharp (Fig. 36F). 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). Lateral carapace margin with 3 large spines, branchial region with strong spine (Fig. 6C, D). Posterior carapace margin with 2 median spines (Fig. 6C, D). Eyes relatively long, thin, slightly curved, with ovoid cornea (Fig. 36F). 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). 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, 41D). 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, 41D). 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). 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, 53G, H). 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, 55D). 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, 52C). 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). Male press-button abdominal locking mechanism submedian in position on sterno-abdominal cavity (Fig. 52C). 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).   
 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) compared to other Maja s. str. species (Fig. 39B, C). The differences in the form of the epistome (relatively longer) (Figs. 39E, F, 41D), presence of distal spines on dorsal margins of the ambulatory meri (Fig. 6C, D, F), and proportionately broader male abdomen (Fig. 47H, I) 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), form of the chelipeds (including the prominent granulation on the carpus) (Fig. 53G, H), and general structure of the G1 (Fig. 7R–T). 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.
description: Published as part of 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, pp. 110-225 in Raffles Bulletin of Zoology 63 on page 128, DOI: 10.5281/zenodo.5384590