Dusky Shoulder Trevally

The duskyshoulder trevally is a small fish reaching only 27 cm in length. The species is similar to other jacks in its overall body profile, having a compressed ovate to oblong shape, with the dorsal profile more convex than the ventral profile. The head profile is gently sloping and slightly convex, with large males having a distinct bulge that is absent in females and juveniles of both sexes. Both of the jaws contain anteriorly widening bands of small villiform teeth, with older individuals also having a number of larger outer teeth. Two separate dorsal fins occur, the first consisting of eight spines and the second of one spine and 20 to 22 soft rays. The anal fin has two detached anterior spines, followed by one spine and 17 to 19 soft rays. The lobe of the soft dorsal fin is falcate, being about the same length as the head. The pelvic fin consists of one spine and 18 or 19 soft rays. The lateral line is moderately curved anteriorly, with the curve having 62 to 72 scales present on it, while the straight section contains three to eight scales and 24 to 32 scutes. The breast of the duskyshoulder trevally is scaleless, extending up to behind the pelvic fin origin and laterally to the pectoral fin base. …

The duskyshoulder trevally inhabits the tropical and subtropical regions of the eastern Indian Ocean and western Pacific Ocean, recorded only from the coastlines of India, Indonesia, Papua New Guinea, northern Australia, and possibly Taiwan. The species probably inhabits offshore areas of more islands in the region, but due to inadequate sampling, has not been recorded. The species lives in waters shallower than 50 m, generally inhabiting the sandy substrates and reefs of the continental shelf, also venturing into bays and inhabiting beaches and mangrove-lined creeks.