A large thresher with very large eyes, an indented forehead, a broad caudal tip, and curved broad-tipped pectoral fins; 1st dorsal fin further back than in other threshers (Ref. 5578). Upper lobe of caudal fin very long and strap-like almost or quite equal to length of rest of shark; lower lobe short but well developed (Ref. 13570). Purplish grey above, cream below, posterior edges of pectoral and pelvic fins and sometimes first dorsal fin dusky; light color of abdomen not expanded over pectoral-fin bases (Ref. 13570).