About Chlorurus japanensis (Bloch, 1789)
Chlorurus japanensis (Bloch, 1789) can be distinguished by its fin ray and spine counts: a total of nine dorsal spines, three dorsal soft rays, three anal spines, and nine anal soft rays. Its body is typically fusiform, or regularly shaped. Additional distinguishing features include four median predorsal scales, two scale rows on the cheek, and an absence of conical teeth on the side of the lower dental plate. For the upper dental plate, initial phase individuals have zero to two conical teeth, while terminal males often have two. The lips partially cover the dental plates. Subadults have a caudal fin that ranges from slightly rounded to truncate, while terminal males have a slightly emarginate caudal fin. Males are distinctly bicolored, with a purple-brown anterior body and an oblique division separating this section from the pale yellow posterior. Females are entirely dark brown, with a red-orange tail. This species is widespread across the Pacific Ocean, and occurs especially in the region stretching from the Ryukyu Islands to Australia. It has also been recently reported from Tonga. Chlorurus japanensis is an oviparous species, and typically forms distinct breeding pairs during reproduction.
