Roughtail Catshark

Probably the smallest member of the G. arae species complex, the roughtail catshark grows no longer than 33 cm (13 in). It has a slender, firm body and a slightly flattened head. The snout is rather long and pointed, with the nostrils divided by triangular skin flaps in front. The horizontally oval eyes are equipped with rudimentary nictitating membranes (protective third eyelids), and lack prominent ridges underneath. There is a tiny spiracle behind each eye. The mouth is large and forms a broad arch, with moderately long furrows around the corners. The teeth are small and number 59–65 rows in the upper jaw and 58–60 rows in the lower jaw. Each tooth has a thin central cusp flanked by 1–3 pairs of cusplets on either side. There are five pairs of gill slits. The first dorsal fin has a blunt apex and is positioned over the latter half of the pelvic fin bases. The second dorsal fin is nearly as large as the first and similar in shape, and positioned over the latter half of the anal fin base. The large, broad pectoral fins have rounded corners. The pelvic and anal fins are low and angular. The anal fin base measures roughly 10–14% of the total length, exceeding the distance between the pelvic and anal fins and about the same as the distance between the dorsal fins. The caudal fin is low, with a small lower lobe and a ventral notch near the tip of the upper lobe. …

While the full extent of its range may remain to be documented, the roughtail catshark seems to have a disjunct distribution that does not overlap with that of either G. antillensis or G. cadenati. The northern population occurs from North Carolina southward to the Caribbean and the Yucatan Peninsula, and westward to the Mississippi River Delta. The southern population is found in the Caribbean Sea off the coasts of Honduras, Nicaragua, and Costa Rica. The roughtail catshark is a demersal species typically inhabiting continental and insular slopes, occasionally venturing onto the shelf. It is abundant but unevenly distributed, with some areas harboring hundreds of sharks and other areas none at all. Sharks of the northern population have been recorded from depths of 36–732 m (118–2,402 ft), and those of the southern population from 338–631 m (1,109–2,070 ft). The shallowest records have tended to come from higher latitudes, suggesting that temperature plays more of a role than depth in determining the species' distribution; it has been captured from water ranging from 5.6 to 11.1 °C (42.1 to 52.0 °F). Both adults and juveniles occur up to a depth of 450 m (1,480 ft), while usually only adults are found deeper. There also appears to be spatial segregation by sex, though the patterns are not well-defined.

The roughtail catshark preys mostly on shrimp, and may gather in sizable schools. Once erroneously reported to be aplacental viviparous, more recent research has confirmed that this species is actually oviparous. Adult females have a single functional ovary, on the right, and two functional oviducts. A single egg matures within each oviduct at a time. The eggs are enclosed within tough, flask-shaped capsules around 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. The rounded upper corners of the capsule bear coiled tendrils. The spawning grounds of this shark may be located in very rough terrain. Both sexes mature sexually at approximately 27–33 cm (11–13 in) long.