The false catshark or sofa shark (Pseudotriakis microdon) is a species of ground shark in the family Pseudotriakidae, and the sole member of its genus. It has a worldwide distribution, and has most commonly been recorded close to the bottom over continental and insular slopes, at depths of 500–1,400 m (1,600–4,600 ft). Reaching 3.0 m (9.8 ft) in length, this heavy-bodied shark can be readily identified by its elongated, keel-like first dorsal fin. It has long, narrow eyes and a large mouth filled with numerous tiny teeth. It is usually dark brown in color, though a few are light gray.