Alcomaja desmondi, 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 : 154

publication ID	https://doi.org/ 10.5281/zenodo.5384590
publication LSID	lsid:zoobank.org:pub:40BCDD62-D35E-46D1-95A3-2CC0DF219DEE
persistent identifier	https://treatment.plazi.org/id/9465E42F-3FEC-4FE0-B6F0-C151940751AF
taxon LSID	lsid:zoobank.org:act:9465E42F-3FEC-4FE0-B6F0-C151940751AF
treatment provided by	Valdenar
scientific name	Alcomaja desmondi
status	sp. nov.

Treatment

Alcomaja desmondi View in CoL n. sp.

( Figs. 17F View Fig , 20R–T View Fig , 36L View Fig , 39N View Fig , 45D View Fig , 49H View Fig , 52F View Fig , 53O View Fig , 55M View Fig )

Material examined. Holotype: male (35.4 × 28.3 mm ( NMCR), Balicasag Island, Panglao, Bohol, Philippines , 200–300 m, coll. local fishermen with tangle nets, June 2002 . Paratypes: Philippines – 2 males (36.6 × 31.7 mm, 27.1 × 23.5 mm) ( ZRC 2013.1273 View Materials ), same data as holotype . — 2 males (27.7 × 21.3 mm, 36.6 × 29.1 mm), 1 ovigerous female (38.0 × 32.6 mm) ( ZRC 2001.0588 View Materials ), Balicasag Island, Panglao, Bohol, 50–500 m, coll. local fishermen with tangle nets, 28 November 2001. — 1 ovigerous female (37.6 × 32.0 mm) (NSMT-Cr 22328), Balicasag Island , Panglao, Bohol, coll. local fisherman via M. Takeda & H. Komatsu, February 2003 .

Diagnosis. Carapace pyriform; dorsal surface of carapace densely covered with long, stiff setae; with small rounded granules ( Fig. 17F View Fig ). Pseudorostral spines with rounded crosssection ( Fig. 36L View Fig ). Antorbital spine strong, curved upwards, appears straight from dorsal view; intercalated spine acutely triangular; postorbital spine very long ( Fig. 36L View Fig ). Lateral and branchial spines strong in juveniles and adults; 3 spines on median row: 2 gastric, 1 cardiac; 2 distinct spines on posterior carapace margin ( Fig. 17F View Fig ). Subhepatic region with numerous very small rounded granules on surface ( Fig. 39N View Fig ). Basal antennal article with numerous granules ( Fig. 39N View Fig ). Ischium of third maxilliped almost smooth to slightly rugose ( Fig. 45D View Fig ). Ambulatory legs relatively short, first leg never twice length of carapace; surfaces strongly setose, covered with long coarse setae ( Figs. 17F View Fig , 55M View Fig ). G1 almost straight with distinct ventral fold ( Fig. 20R–T View Fig ).

Etymology. The name is formed to honor Desmond Griffin, a carcinologist who devoted a large part of his life to the taxonomy of Indo-West Pacific majoid crabs.

Remarks. Alcomaja desmondi n. sp. superficially resembles Holthuija suluensis ( Rathbun, 1916) , in general shape, especially since both species have strong lateral and branchial spines as well as two gastric spines on the carapace. Excluding the generic level differences, A. desmondi has a more rounded carapace, especially on the branchial regions; the pseudorostral spines are more diverging in Holthuija suluensis ; the first gastric spine is placed more anteriorly in A. desmondi ; the antorbital spine is straight and directed outwards in A. desmondi (versus curved and directed anteriorly in H. suluensis ), and the setae covering the ambulatory legs in A. desmondi are longer and stiffer compared to H. suluensis .

Within Alcomaja , A. desmondi stands out in several features. It is unique among members of the genus in possessing long stiff setae covering its carapace and legs; and the G1 structure is atypical, being almost straight, much stouter with an unusually broad ventral flap ( Fig. 20R–T View Fig ). Since the rest of its characters agree with Alcomaja as presently defined, it seems best to leave it in this genus for the time being

The dense stiff setae on the specimens of A. desmondi from Balicasag trap a thick layer of silicate sponge spicules, which makes their handling very difficult. It appears to be a species living in the deep sea on the deep steep rocky slopes of Balicasag Island at depths exceeding 300 m.