… was a family of marine actinopterygian fish. They were most diverse throughout the Cretaceous period, though Thrissops fossils are known from the Oxfordian-Kimmeridgian boundary in the Late Jurassic. Most ichthyodectids ranged between 1 and 5 meters (3–15 ft) in length. All known taxa were predators, feeding on smaller fish; in several cases, larger Ichthyodectidae preyed on smaller members of the family. Some species had remarkably large teeth, though others, such as Gillicus arcuatus, had small ones and sucked in their prey. (Wikipedia)
Image: Dmitry Bogdanov
1 - Xiphactinus audax; 2 - Ichthyodectes ctenodon; 3 - Cladocyclus gardneri; 4 — Chirocentrites coronini.