Hexanchus griseus

Hexanchus griseus (Bonnaterre, 1788) English common name: bluntnose sixgill shark Spanish common name: tiburón leche (Figs 2, 3; Table 1) Material examined. CIFI-2400, 3260 mm TL, male; ca. 20.4 km to the North of Salinas Roca Partida, Veracruz, Mexico (Fig. 1); 21 Jul. 2024; Armando Campos Pérez leg. Description. Table 1. Robust body, large and broad head, head length (HL) 14.7 % of TL. Snout wide (27 % HL), big mouth and ventral arched with symphyseal tooth on both jaws and six rows of large, serrated comb-shaped teeth on each side of lower jaw. Ten teeth on each side of upper jaw with hooked cusp, not counting smallest and molariform ones. Six large gill slits not inserted on pectoral fins. Eye small (13.3 % HL), pupil dark with white rim, prominent tapetum lucidum giving a fluorescent greenish coloration in life. Single dorsal fin originating ahead of anal fin insertion. Short caudal peduncle (8.3 % TL). Asymmetric caudal fin. For all measurements see Table 1. Specimen sexually mature, testes elongated, vascularized, with well-developed vas deferens and, along with seminal vesicles, filled with sperm. Clasper calcified, mobile, and presented several hematomas. Coloration. The live specimen had green eyes, the dorsolateral region greyish in color with brown tones, and pale grey in the ventrally (Fig. 2). After its capture, while frozen and fresh, the dorsolateral coloration was darker brown, and the ventral region grayish (Figs 3, 4).