Labuanium trapezoideum (H. Milne Edwards, 1837)

Fig. 2F

Sesarma oblonga von Martens 1868: 611 .— Estampador 1937: 538; 1959: 96

Sesarma trapezoidea, De Man 1887: 654 .— Ortmann 1894: 719.— Estampador 1937: 537.

Sesarma trapezoidae [sic], Estampador 1959: 95.

Material examined. 2 females, 38.3 by 42.0 mm, 34.2 by 36.0 mm (ZRC; NJL160501–02), Layawan River, Brgy. Toliyok, Oroquieta, Misamis Occidental, Mindanao Island, Philippines, coll. N.J. Lagare, 16 Sep. 2016 .

Remarks. Von Martens (1868) described Sesarma oblonga from Samar Island and provided a short description but no figure. De Man (1887) subsequently synonymized this species with Sesarma trapezoidea H. Milne Edwards, 1837 (type locality: unknown), after comparing the types. Estampador (1937, 1959), apparently unaware of the synonymization, recorded both names from the literature. There have been no other new records of this species from the Philippines since then. Serène & Soh (1970) later established a new genus, Labuanium, and placed S. trapezoidea under this genus.

Labuanium trapezoideum has also been reported from Fiji, Tahiti, Australia (Queensland), Indonesia (Ambon, Halmahera, Sulawesi), Japan (Ryukyu), and Taiwan (De Man 1887, 1889, 1902; Ortmann 1894; Rathbun 1907; Davie 2002; Jeng et al. 2003; Maenosono & Naruse 2016).

The present specimens were collected from the foothills of Mt. Malindang Range in Oroquieta, Misamis Occidental province. The crabs were found during the day on a cliff side overlooking a fast-flowing river, about 8.3 km inland at an elevation of 91 masl.

New Mindanao record.