Longfin Sawtail Catshark

The longfin sawtail catshark reaches a maximum known length of 35 cm (14 in), smaller than G. antillensis and comparable to G. arae. This species is slender, with a broad head and a moderately long, pointed snout. The large eyes are horizontally oval, equipped with rudimentary nictitating membranes (protective third eyelids), and lack prominent ridges underneath. A modest spiracle is located behind each eye. The nostrils are large and partially covered by anterior triangular flaps of skin. The mouth is wide and curved, with fairly long furrows around the corners. The teeth have a long central cusp flanked on either side by one or two pairs of lateral cusplets. The upper jaw of the type specimen contained 62 tooth rows. The five pairs of gill slits are small, with the fourth and fifth pairs located over the pectoral fin bases.

The two dorsal fins are similar in size and shape, with blunt apexes. The first dorsal fin originates over the midpoint of the pelvic fin bases, while the second originates over the midpoint of the anal fin base. The pectoral fins are large and broad, with rounded corners. The pelvic and anal fins are low and angular in shape. The anal fin base is distinctively long compared to the other members of the G. arae complex, measuring 13–16% of the total length. The caudal fin has a small, rounded lower lobe and a ventral notch near the tip of the upper lobe. …

The longfin sawtail catshark does not co-occur with either G. arae or G. antillensis. It has only been found in the Caribbean Sea off Panama and Colombia, though confusion with its sister species could have obscured the full extent of its distribution. Demersal in nature, it is a rare inhabitant of the upper continental slope, at depths of 431 to 549 m (1,414 to 1,801 ft).

Little is known of the natural history of the longfin sawtail catshark. Reproduction is oviparous; mature females have a single functional ovary, on the right, and two functional oviducts. A single egg matures within each oviduct at a time. The egg is enclosed within a flask-shaped capsule roughly 4.9–5.1 cm (1.9–2.0 in) long, 1.2–1.4 cm (0.47–0.55 in) across the top, and 1.6 cm (0.63 in) across the bottom; there are coiled tendrils at the upper two corners. Females mature at about 29–34 cm (11–13 in) long; adult males are unknown and the largest known immature male measured 29 cm (11 in) long.