over the pectoral fin bases. The first dorsal fin is roughly triangular, with gently convex anterior and posterior margins, and originates over the midpoint of the pelvic fin bases. The second dorsal fin is slightly smaller than the first and similar in shape, and originates over the latter portion of the anal fin base. The pectoral fins are medium-sized and broad. The pelvic fins are sizable and relatively low, with angular corners. In adult males, the inner margins of the pelvic fins are partially fused to form an "apron" over the bases of the claspers, which are very long and thin, reaching past the origin of the small anal fin. The base of the anal fin measures 8–10% of the total length, much less than the distances between either the pelvic and anal fins or the two dorsal fins. The anal fin of the male is 2% shorter than that of the female, which may be related to the function of the unusually long claspers. The caudal peduncle is almost cylindrical, and leads to a low caudal fin with a small lower lobe and a ventral notch near the tip of the upper lobe. The dermal denticles are small and overlapping, each with a leaf-shaped crown bearing a median ridge and three marginal teeth. There is a saw-toothed crest of enlarged denticles along the upper edge of the caudal fin. This species is dark gray above, with a series of faint darker saddles along the body and tail. The underside, inside of the mouth, and trailing margins of the pectoral and dorsal fins are white. Biology and ecology The broadfin sawtail catshark is an opportunistic predator known to consume a wide variety of bony fishes (including Sardinops melanostictus, Glossandon semifasciatus, Chlorophthalmus albatrossis and lanternfishes), cephalopods (including sepiolid and enoploteuthid squid), and crustaceans (including isopods, krill, and decapods). Young sharks exhibit greater variation in diet across seasons than immature and mature sharks, which consistently feed predominantly on fish. The dietary composition of young sharks in Suruga Bay differs from that of the co-occurring gecko catshark (G. eastmani), perhaps to reduce interspecific competition. Reproduction in the broadfin sawtail catshark is oviparous; adult females have a single functional ovary, on the right, and two functional oviducts. Only a single egg may mature within each oviduct at a time. The egg case is vase-shaped and measures roughly long and across, with thick, opaque, brown