PROSCYLLIIDAE FINBACK CATSHARKS

Proscylliidae or common name Finback catsharks belong to the order Carcharhiniformes or common name Ground sharks. These sharks are dwarf to small in size, ranging from 15-65 cm/5.9 inches-2 feet in total length. Their heads are narrow and rounded, with a subangular snout that does not have a deep groove in front of the eyes, nor do they nasoral grooves or barbels. The internarial space is less than 1.3 times that of the nostril width. The eyes are cat-like and elongated. They have rudimentary nictitating membranes. The mouth is arched, angular and long that reaches past the anterior ends of the eyes. There are also small papillae on the palate and edges of the gill arches. Labial furrows are either extremely short or absent altogether.

The first dorsal fin base is short, and ahead of the pelvic fin bases, but closer to the pelvic fin bases, than the pectoral fin bases. There are no precaudal pits. The caudal fin lacks a strong ventral lobe or lateral undulation on the dorsal margin. The color of the body and fins is typically variegated, with the exception of the genus Eridacnis, having plain colored bodies and striped caudal fins.

The Finback catsharks can be found in warm seas worldwide and are often the most abundant and common shark in tropical regions. They are considered deep-water sharks found on the outer continental and insular shelves and upper slopes on or near the bottom between 50-766 m. Distribution is mostly in the Indo-west Pacific region, but also can be found in the northwest Atlantic Ocean. They have been documented and seen primarily in Japan, Myanmar, the Philippines, South Africa, Mozambique, Tanzania, and Somalia.

They are generally slow-moving predators that feed on bony fish and small invertebrates. Although most are ovoviviparous and have live young, one is confirmed to be oviparous (with the possibility of another), having one egg per uterus, laying these eggs with almost fully developed young. These egg cases, known as mermaid’s purses, are unique in appearance to other species of sharks that lay eggs. It has been recently discovered that the Pygmy Ribbontail Catshark is capable of fluorescence.

The Finback catsharks are not targeted by humans for fishing or consumption. Although not endangered or threatened, they are negatively impacted by fisheries as a result of bycatch. The shrimping industry has affected them the most.