Hexapus sexpes ( Fabricius, 1798 )

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2015, Notes on Hexapodidae (Crustacea, Brachyura) from Indonesia and Malaysia, with description of a new species of Mariaplax Rahayu & Ng, 2014, from Lombok, Indonesia, Zootaxa 3981 (1), pp. 125-137 : 126

Hexapus sexpes ( Fabricius, 1798)

( Fig. 1 A, B)

Cancer sexpes Fabricius, 1798: 334 .

See Rahayu & Ng (2014: 400) for the complete synonymy.

Material examined. Peninsular Malaysia: 2 males (7.3 × 4.5 mm, 6.0 × 3.6 mm), 1 female (7.6 × 4.7 mm) ( ZRC), station D, Jeram Polychaete Reef, intertidal muddy shore and intermittent sabellariid reefs, lower, lowest shore, Jeram, Kuala Selangor, 3°13'27"N 101°18'13"E, coll. J. J. Eeo, July–October 2013.

Remarks. Rahayu & Ng (2014) revised the taxonomy of the species and clarified its identity based on material from Phuket in western Thailand. Velip & Rivonker (2014) examined the type material of Hexapus estuarinus Sankarankutty, 1975 , from southern India, and commented that it was a valid species and not synonymous with H. sexpes . They argued that the structure of the chela (with a basal tooth on the dactylus of the major chela) was different, that there was a large gap between the closed fingers of the minor chela, setae at the base of the propodal finger was absent, and tubercles were present on the thoracic sternum. The differences observed for the chela are subject to size (the type of H. sexpes is relatively smaller than that of H. estuarinus ), however, and this structure is also known to vary to some degree. We do not regard these differences as substantial; they certainly agree very well with the material identified as H. sexpes by Rahayu & Ng (2014), the redescription of the type male by Manning (1982), and the present material here from Malaysia. As such, we prefer to regard them as synonymous for the time being. The presence of the species in the Straits of Malacca, Peninsular Malaysia is nevertheless noteworthy.

Three species of Hexapus are now known: Hexapus bidentatus Velip & Rivonker, 2014 , Hexapus sexpes ( Fabricius, 1798) and Hexapus timika Rahayu & Ng, 2014 .

Figures

FIGURE 1. Overall habitus. A, Hexapus sexpes (Fabricius, 1798), male (7.3 × 4.5 mm, 6.0 × 3.6 mm) (ZRC), Jeram, Peninsular Malaysia; B, Hexapus sexpes (Fabricius, 1798), female (7.6 × 4.7 mm) (ZRC), Jeram, Peninsular Malaysia; C, Hexapinus latus Rahayu & Ng, 2014, female (7.3 × 4.2 mm) (NNM-ZMA Crust De 241762 b), Paternoster Islands.