Cow sharks [Hexanchidae]

Description

Hexanchidae, commonly known as cow sharks, are distinguished by their six or seven pairs of gill slits—the only sharks with such a feature. Members of this family, such as the broadnose sevengill shark (Notorynchus cepedianus) and the bluntnose sixgill shark (Hexanchus griseus), are typically found in deep waters worldwide. They have a unique appearance with a single dorsal fin set far back on their bodies and large, luminous eyes adapted to the dim light of their deep-sea habitats. Cow sharks are thought to be among the most ancient of living shark lineages, showcasing a primitive jaw structure and other characteristics.

Genera

Taxonomy