Cyrtomaia horrida Rathbun 1916

Takeda, Masatsune, Ohtsuchi, Naoya & Komatsu, Hironori, 2021, Crabs (Crustacea, Decapoda) from the Sea off East and Southeast Asia collected by the RV Hakuhō Maru (KH- 72 - 1 Cruise) 1. Sulu Sea and Sibutu Passage, Bulletin of the National Museum of Nature and Science. Series A, Zoology 47 (2), pp. 65-97 : 82

Cyrtomaia horrida Rathbun 1916

( Figs. 12A–C )

Material examined. RV Hakuhō Maru KH-72-1 cruise, sta. 12 (Sulu Sea ; 08°19.0′N, 118°09.1′E – 08°18.7′N, 118°08.5′E; 495–500 m deep); 3 m beam trawl; 26 May, 1972; 1 ˁ( Fig. 12A ) ( CB 15.2 mm excluding branchial spines; CL 15.0 mm excluding pseudorostral spines), NSMT-Cr 28972; 1 ˁ ( Fig. 12B–C ) ( CB 9.0 mm; CL 8.3 mm), NSMT-Cr 28973 .

Remarks. Among the known species of the genus Cyrtomaia , the taxonomic validity and status of C. horrida pilosa Ihle and Ihle-Landenberg, 1931 known only by the holotype from the Kei Islands, has been long discussed. It was considered as synonymous with C. horrida by Griffin (1976), but Guinot and Richer de Forges (1982) examined the holotype and tentatively elevated this taxon to the full species. Later, Guinot and Richer de Forges (1986) and Griffin and Tranter (1986) also considered it as a synonym of C. horrida . Recently, however, Richer de Forges and Ng (2007), who examined a long series of the specimens from the Bohol Sea, confirmed that the females of C. horrida are somewhat more pilose than the males especially in the small specimens, and decidedly synonymized C. horrida pilosa with C. horrida . At present, the genus Cyrtomaia is comprised of 29 species from the Indo-Pacific waters ( Richer de Forges and Ng, 2007, 2009a; Ng et al., 2008).

In the specimens at hand, all the chelipeds and ambulatory legs are missing, but the spinulation of the carapace surface agrees well with the description and figures by Guinot and Richer de Forges (1982: Fig. 24, as? Cyrtomaia pilosa ), though the carapace ( Fig. 12A–B ) is not pilose as in the holotype. They also agree essentially with the description by Guinot and Richer de Forges (1982), though the G1 may be not fully developed and rather similar to that of C. suhmi Miers, 1886 in general structure. According to Griffin and Tranter (1986), C. suhmi , C. smithii Rathbun, 1893 and C. owstoni Terazaki, 1903 have a slen- der simple type of the G1.

Distribution. West Pacific from Japan to the Solomon Islands through the Philippines, the South China Sea and Indonesian waters; 24–787 m deep.

Figures

Fig. 12. A–C: Cyrtomaia horrida Rathbun, 1916, male (A) (NSMT-Cr 28972. CB 15.2mm excluding branchial tubercles; CL 15.0mm excluding pseudorostral spines), male (B–C) (NSMT-28973. CB 8.3mm; CL 9.0 mm). D–E: Cyrtomaia largoi Richer de Forges and Ng, 2007, female (D) (NSMT-Cr 28974. CB 22.7mm; CL 20.9mm excluding pseudorostral spines), male (E) (NSMT-Cr 28991. CB 7.7mm; CL 8.3mm). F: Platymaia remifera Rathbun, 1916, female (NSMT-Cr 28977. CB 31.6mm; CL 28.7mm including rostral spine).