Atlantic Sawtail Catshark

The Atlantic sawtail catshark reaches a maximum known length of 45 cm (18 in). Slender and firm-bodied, it has a slightly flattened head with a moderately long, flattened snout. The head is proportionately shorter and narrower, and the nostrils relatively farther from the snout tip, than in G. melastomus. The nostrils are partially covered by triangular flaps of skin on their anterior rims. The eyes are horizontally oval and equipped with rudimentary nictitating membranes (protective third eyelids). There is a slight ridge below each eye, and a minute spiracle behind. The large mouth is wide and curved, with rather long furrows around the corners. The small teeth each have a narrow central cusp flanked by multiple smaller cusplets on either side. There are five pairs of gill slits. The first dorsal fin is positioned over the latter portion of the pelvic fin bases, while the second is positioned over the latter portion of the anal fin base. Both dorsal fins are angular and similar in size. The pectoral fins are large and wide, with rounded corners. The short, low pelvic fins are placed close to the anal fin, which is elongated and angular. The caudal peduncle is compressed from side to side; its height is greater than in G. melastomus, exceeding 4.5% of the total length. The caudal fin is low, with a small lower lobe and a ventral notch near the tip of the upper lobe. …

The Atlantic sawtail catshark is found from Cape St. Vincent in southwestern Portugal, through the Strait of Gibraltar into the Alborán Sea, to as far as Cabo de Gata in southwestern Spain. It is most abundant in the center of the Alborán Sea, and around Isla de Alborán. This species has been recorded a few times off Morocco and once off Mauritania; it may be extremely rare or mistaken for G. melastomus in the region. Its total range has been estimated to encompass 50,000 km2 (19,000 mi2), about evenly divided between the northeastern Atlantic and the western Mediterranean. Demersal in nature, the Atlantic sawtail catshark inhabits the continental slope at a depth of 330–790 m (1,080–2,590 ft), and is most common between 400 and 600 m (1,300 and 2,000 ft). There is a lone record from shallower than 50 m (160 ft). This species does not exhibit spatial segregation by either sex or size, or conduct seasonal migrations.

The Atlantic sawtail catshark is rarer than the blackmouth catshark, which shares its range. Its natural history is poorly understood. Reproduction is oviparous, with mating and spawning proceeding throughout the year. Females can contain up to nine maturing eggs at a time, divided between the two functional oviducts. The tough egg case is flask-shaped and reddish, with a rounded bottom and a pair of "horns" at the top, and measuring around 3.1–3.8 cm (1.2–1.5 in) long and 1.1–1.3 cm (0.43–0.51 in) across. The egg case of G. melastomus is similar in appearance but significantly larger. Once deposited, the egg hatches within a short period of time. According to Compagno (2005), males attain sexual maturity at about 38–42 cm (15–17 in) long, and females at about 40–45 cm (16–18 in) long. Rey and colleagues (2010) reported the smallest mature males and females in their study to be 33 cm (13 in) and 37 cm (15 in) long respectively.