between the northeastern Atlantic and the western Mediterranean. Demersal in nature, the Atlantic sawtail catshark inhabits the continental slope at a depth of , and is most common between . There is a lone record from shallower than . This species does not exhibit spatial segregation by either sex or size, or conduct seasonal migrations. Description The Atlantic sawtail catshark reaches a maximum known length of . 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 skin is covered by dermal denticles, each with a leaf-shaped crown bearing a median ridge and three marginal teeth. A prominent crest of enlarged denticles runs along the front portion of the dorsal caudal fin margin. The coloration is gray above and pale below, with a series of dark gray saddles or blotches along the back and tail. The dorsal fins are dusky at the base and lighten towards the trailing margins. The trailing margin of the caudal fin is black, as is the interior of the mouth. The inside of the furrows at the corners of the mouth are dark, in contrast to G. melastomus where they are