Atelmyteridae

Atelmyteridae is a family of extinct marine reptiles belonging to the order Plesiosauria. Fossils attributed to this family have been found in the Late Cretaceous period, primarily in Europe. The name Atelmyteridae, meaning "untrimmed swimmer," reflects their presumed adaptations for aquatic life.

These plesiosaurs are characterized by certain anatomical features, including a relatively short neck compared to some other pliosaur groups and distinct cranial features. Their exact phylogenetic placement within the broader plesiosaur radiation has been subject to some debate, but they are generally considered to be within the Pliosauria suborder, which are plesiosaurs with generally shorter necks and larger heads than long-necked pliosaurs.

The known fossil record of Atelmyteridae is limited, with only a few species described. This scarcity of specimens makes a comprehensive understanding of their biology and evolutionary relationships challenging. However, the available evidence suggests they were marine predators, likely feeding on fish and other marine invertebrates. Their distribution appears to have been localized, indicating a specialized ecological niche within their Cretaceous marine environments. Further discoveries are needed to fully elucidate the diversity and paleobiology of this intriguing extinct family.