Sakaija sakaii ( Takeda & Miyake, 1969 )

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 : 169-170

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/03A9654B-FFBA-0764-54FC-FC9E7A81FB76
treatment provided by	Valdenar
scientific name	Sakaija sakaii ( Takeda & Miyake, 1969 )
status

Treatment

Sakaija sakaii ( Takeda & Miyake, 1969) View in CoL

( Figs. 28D–G View Fig , 33H–J View Fig , 46H View Fig )

Maja sp. – T. Sakai, 1932: 50, pl. 2 fig. 5, text fig. 5.

Maja japonica View in CoL – T. Sakai, 1934: 297, text-figs. 10. – T. Sakai, 1936: 99, pl. 25, fig. 2, text-fig. 45. – T. Sakai, 1938: 299, pl. 30, fig. 2. – Takeda, 1982: 128. (not Maja japonica Rathbun, 1932 View in CoL ).

Maja sakaii Takeda & Miyake, 1969: 512 View in CoL , pl. 17, fig. C. – Serène & Lohavanijaya, 1973: 50 (key). – T. Sakai, 1976: 237, fig. 125a, b, pl. 85 fig. 2. – Huang, 1989: 339. – Takeda, 1993: 43. – Huang, 1994: 583. – Yang et al., 2008: 780. – Ng et al., 2008: 117 (list).

Material examined. Japan – 1 male (9.0 × 6.6 mm) (NSMT- Cr 8094), station 12, Shimoda, Shizuoka Prefecture, coll. M. Takeda, 9 November 1981 .

Diagnosis. Carapace branchial area gently inflated, ovate; with relatively short lateral and branchial spines ( Fig. 28D, E, G View Fig ). Pseudorostral spines short, diverging ( Fig. 28D–G View Fig ). Supraorbital eave gently curved; antorbital spine short, triangular, sharp; intercalated spine triangular, separated from adjacent spines by large gaps; postorbital spine longest, triangular, pointed anteriorly; hepatic spine short, pointed outwards ( Figs. 28A–C View Fig ). Lateral margin with 2 short spines, posterior one larger; branchial region with 1 spine; median row with 4 low spines or tubercles: 2 gastric (very low), 1 cardiac (long), 1 intestinal (low); 2 short spines on posterior carapace margin ( Fig. 28D, E, G View Fig ). Basal antennal article long with several granules, 2 strong distal spines ( Fig. 28F View Fig ). Ischium of third maxilliped weakly granulated ( Fig. 46H View Fig ). Ambulatory legs relatively long, slender ( Fig. 28D, G View Fig ). G1 gently curved, distal part relatively short, subspatuliform, lined with long setae ( Fig. 33H–J View Fig ).

Remarks. The identities of S. japonica and S. sakaii have been confusing. Tune Sakai (1932) first reported a 14.5 by 13.0 mm male specimen as “ Maja sp. ” from Sagami Bay that he thought was close to Maja japonica Rathbun, 1932 , but believed it to be a juvenile, and hence was uncertain of its identity. Tune Sakai (1934) later realised that there were two forms in Japan and both Rathbun (1932) and Yokoya (1933) had used the same name “ Maja japonica ” independently of each other. Tune Sakai (1934), however, identified one male specimen from the East China Sea as “ M. japonica Rathbun, 1932 ”, and another female specimen from Nagasaki as “ M. japonica Yokoya, 1933 ”. He noted that their carapaces, ambulatory leg and G1 structures were starkly different. Believing that his “ M. japonica ” was conspecific with Rathbun’s (1932) species, and since the name Maja japonica Yokoya, 1933 , was preoccupied by Maja japonica Rathbun, 1932 , T. Sakai (1934) gave a replacement name, Maja nipponensis for Yokoya’s species (see also T. Sakai, 1936, 1938). Tune Sakai (1965) examined the type of Maja japonica Rathbun, 1932 , and realised it was actually conspecific with Maja japonica Yokoya, 1933 , as was M. nipponensis T. Sakai, 1934 . He also noted that the species he had identified as “ Maja japonica ” in 1934 was an undescribed species, but he did not name it.

Takeda & Miyake (1969: 512) agreed that what T. Sakai (1934, 1936, 1938, 1965) had originally identified as “ Maja japonica ” was a separate but unnamed species for which they chose a new name, Maja sakaii . However, since they also designated an ovigerous female measuring 12.9 by 10.0 mm from the East China Sea as the holotype of M. sakaii , they were in effect establishing a new species and not just providing a replacement name.

Sakaija japonica is certainly similar to S. sakaii , and most of the distinguishing characters originally highlighted by T. Sakai (1934) still apply (see also Takeda & Miyake, 1969). The shape of the carapace is diagnostic, with M. japonica more rounded ( Fig. 28A–C View Fig ) while S. sakaii is distinctly pyriform ( Fig. 28D, E, G View Fig ). The difference in carapace shape does not appear to be completely size-dependent in members of this genus. In S. serenei n. sp., for which a good series of specimens is available for study, the carapace shape changes only slightly with larger specimens more rounded ( Fig. 30 View Fig ) but never reaching the condition of S. japonica ( Fig. 28A–C View Fig ). Takeda & Miyake’s (1969) adult holotype female of S. sakaii measures 12.9 by 10.0 mm but its carapace is still distinctly pyriform. Another key character is the proportions of the ambulatory legs. In S. japonica , the merus is notably shorter and stouter ( Figs. 28A–C View Fig , 31C View Fig ) while those of S. sakaii are relatively more slender and longer ( Fig. 28D, G View Fig ).

The G1 structures are quite different. The G1 structures figured for the two species in T. Sakai (1934: text fig. 11) show two different structures and have been used in all subsequent papers by T. Sakai (1934, 1938, 1976) to separate the two species. The G1 of S. japonica provided (as Maja nipponensis ; T. Sakai, 1934: text fig. 11b) is that of a small male from Sagami Bay, measuring 14.5 by 13.0 mm (cf. T. Sakai, 1932: 50, 51) ( Fig. 33G View Fig ). In larger males, the distal part of the G1 is more elongate and has even more long setae ( Fig. 33A–F View Fig ). The G1 of S. sakaii figured (as Maja japonica ; Sakai, 1934: text fig. 11a), apparently from a small male, is drawn at a marginal view and from a different angle from that of S. japonica s. str., and shows an ovate distal part densely lined with setae ( Fig. 33H View Fig ). The young male specimen of S. sakaii examined in this study has the same kind of G1 although the distal part is slightly less expanded and has less setae ( Fig. 33I, J View Fig ), differences easily attributed to their size. The kind of G 1 in S. sakaii , however, is quite different from that of S. japonica . While the G1 of S. japonica is dorsoventrally flattened, like most of the G1s of this genus (with the exception of S. santo n. p.), that of S. sakaii is actually more laterally flattened, such that the longitudinal groove is not on the inner margin (as in S. japonica , Fig. 33A–F View Fig ) but is fully exposed from the abdominal (ventral) view ( Fig. 33H–J View Fig ). In the form of the G1, S. sakaii is closer to S. santo from Vanuatu and New Caledonia ( Fig. 33S–U View Fig ) (see discussion for that species).

Sakaija sakaii (like S. japonica ) is superficially similar to Alcomaja nagashimaensis in being a relatively smaller species in which males have inflated chelipeds. Alcomaja nagashimaensis can easily be separated not only by the previously discussed generic characters, it can also be distinguished by the carapace possessing proportionately longer and sharper lateral and median spines; the fingers of the adult chelae are less curved and the basal antennal article is smoother ( Figs. 17A–C View Fig , 39O View Fig , 41H View Fig ).

The figure of S. sakaii in Miyake (1983) more closely resembles S. japonica with its rounded carapace and is referred there. Huang’s (1989, 1994) records from the East China Sea are probably true S. sakaii . Serène & Vadon’s (1981) record from the Philippines is here referred to S. serenei . Griffin & Tranter’s (1986) records from the Lesser Sunda Islands, Moluccas, Ambon and Java Sea are uncertain. Whether their material is really S. sakaii , or a separate Sakaija species will have to be determined through a re-examination of their material.