Selenophidium

Selenophidium is a genus of extinct marine reptiles belonging to the family Pliosauridae, a group of plesiosaurs. These marine reptiles lived during the Early Cretaceous period. The name "Selenophidium" is derived from Greek words, with "selene" meaning moon and "ophis" meaning serpent, likely referring to the shape of their fossils or their serpentine necks.

Fossils attributed to Selenophidium have been found in various locations, primarily in Europe. These discoveries have provided insights into the morphology and evolutionary relationships of pliosaurs. Selenophidium possessed a characteristic pliosaurian build, featuring a relatively short neck compared to their long-bodied, paddle-limbed forms. Their powerful jaws were equipped with sharp teeth, indicating they were likely apex predators in their marine environments.

The exact phylogenetic placement of Selenophidium within Pliosauridae has been subject to debate among paleontologists. While some classifications consider it a distinct genus, others have suggested it might be synonymous with or closely related to other well-known pliosaur genera. The limited number of complete specimens has contributed to these ongoing discussions. Despite these taxonomic uncertainties, Selenophidium represents an important component of the Early Cretaceous marine ecosystem, offering clues about the diversity and adaptations of large marine reptiles during this period.