Macrophthalmus (Macrophthalmus) sulcatus malaccensis Tweedie, 1937

(Figs. 2 E, F)

Macrophthalmus sulcatus H. Milne Edwards, 1852: 156

Macrophthalmus dilatatus sulcatus — Barnes 1970: 216, fig. 4.

Macrophthalmus (Macrophthalmus) malaccensis Tweedie, 1937: 167, fig. 9. Macrophthalmus (Macrophthalmus) sulcatus malaccensis — Barnes 2010: 35 (key), 40.

Material examined. 1 male (7.34 x 16.71 mm) (RCLA-C.B.0278), Kamora, Papua, 25.06.2008.

Remarks. Barnes (2010) divided M. sulcatus into a western form, M. sulcatus sulcatus and an eastern form, M. sulcatus malaccensis Barnes, 1970 . The male in this study is smaller than those described for M. sulcatus malaccensis by Barnes (1970; 2010), i.e. the carapace is broader than that of M. abbreviatus; the exorbital angle is small, with the tip directing downwards and the tip of the cornea is not projecting beyond the tip of the second anterolateral tooth. Barnes (1970) also mentioned that the carapace of M. sulcatus is covered by dense, medium-size granules while the carapace of the Papua specimen is smooth except for very small granules on the lateral surface around the lateral teeth, and the clumps of granules on the branchial region are indistinct. It is possible that the granulation on the carapace is varies according to the size of the animal.

Habitat. Muddy substrate of landward fringe of mangrove forests.

Geographical distribution. Mauritius, Singapore, Malaysia, Philippines, Japan (Barnes 1970), and now Papua.