Southern Sawtail Catshark

The largest known specimen of the southern sawtail catshark measured 43 cm (17 in) long. This species has a slender body and a moderately short, flattened head with a pointed snout. The eyes are horizontally oval and have rudimentary nictitating membranes (protective third eyelids); they are followed by tiny spiracles. The ridge beneath each eye is indistinct. The anterior rims of the nostrils are enlarged into triangular skin flaps. The large mouth forms a short, wide arch, with fairly long, deep furrows around the corners; males have a slightly longer, narrower mouth and larger teeth than females. There are around 57–71 upper tooth rows and 56–63 lower tooth rows. Each tooth has a narrow central cusp flanked by one or two smaller cusplets on either side. There are five pairs of gill slits, with the fourth and fifth over the pectoral fin bases. The first dorsal fin originates over the rear of the pelvic fins, while the second dorsal fin originates over the rear of the anal fin. Both dorsal fins are small with rounded apexes; the first is slightly smaller than the second. The pectoral fins are fairly large, with rounded corners. The pelvic fins are small and relatively broad; adult males have rather short, thick claspers that bear hooks on their inner surfaces. …

The only Galeus species in the southwestern Atlantic, the southern sawtail catshark is found off the southern Brazilian states of Rio Grande do Sul and Santa Catarina, and may occur as far north as São Paulo. Its total range is estimated to encompass less than 20,000 km2 (7,700 sq mi) of area. This species has been recorded from between the depths of 236 and 600 m (774 and 1,969 ft), but is most common below 400 m (1,300 ft). Demersal in nature, it favors deepwater reefs on the upper continental shelf, that are rich in sea fans, hard corals, sponges, crinoids, and brittle stars.

The southern sawtail catshark shares its habitat with the abundant freckled catshark (Scyliorhinus haeckelii). Reproduction is oviparous. Adult females have a single functional ovary, on the right, and two functional oviducts; a single egg matures within an oviduct at a time. The egg is enclosed in a reddish vase-shaped capsule, measuring roughly 5–6 cm (2.0–2.4 in) long and 4 cm (1.6 in) wide. with coiled tendrils at the four corners. Males and females reach sexual maturity at 36–38 cm (14–15 in) and 35–39 cm (14–15 in) long respectively.