A new species of Thrissina from Pakistan (Arabian Sea), with redescription of Thrissina whiteheadi (Wongratana 1983) (Clupeiformes: Engraulidae)

Abstract

Thrissina supra sp. nov. is described based on 15 specimens collected from Sindh, Pakistan. The new species is closely related to Thrissina whiteheadi (Wongratana 1983), which is herein redescribed, both species having a relatively long upper jaw with the posterior tip slightly beyond the opercle posterior margin, the snout tip above the eye center level, similar numbers of gill rakers, ventral scutes, and fin rays, and the first supramaxilla absent. However, the former is characterized by higher counts of longitudinal scale rows (45–47 vs. 40–42 in T. whiteheadi), transverse scales (12 or 13 vs. 10 or 11), total gill rakers on the first, second, third, and fourth gill arches [35–39, 33–37, 22–24, and 18–22, respectively vs. 30–34 (rarely 36), 29–32 (34), 19–21 (23), and 15–18 (14, 19), respectively], and branched anal-fin rays [42–45 (rarely 40) vs. 39–42 (43)], a longer snout (3.7–4.1% SL vs. 3.1–3.6%), pelvic fin (9.0–10.4% SL vs. 7.7–9.0%), and mandible (17.3–18.3% SL vs. 15.4–17.2%), a shorter pelvic-fin insertion to anal-fin origin distance (17.0–18.8% SL vs. 19.1–24.2%), and distinct paired dark lines along the dorsum from the occiput to the caudal-fin base (vs. uniformly distributed dorsal melanophores).