Abstract
A single female specimen of a rare euryplacid crab species, Trissoplax dentata (Stimpson, 1858), was collected from a muddy tidal flat on Okinawa Island, Ryukyu Islands, Japan. Although this species has previously been recorded based on specimens from several localities in Japan, morphological information on those specimens has not been provided. This species is distinguished from the congener, T. tuberosa Castro and Ng, 2010, by the presence of an inner tooth and a median lobe on each suborbital border, and a tomentum on the dorsodistal regions of the cheliped carpi, and the absence of conical tubercles on the outer surfaces of the chelae. This study is the first to present the morphological features of a Japanese specimen.
