Ectenotheriid

Ectenotheriid is a proposed taxonomic family of extinct marine reptiles. The name refers to the genus Ectenotherium, which is the type genus for this group. Members of this proposed family are thought to have been mosasaurs, a group of large, predatory marine lizards that lived during the Late Cretaceous period. The fossil record for ectenotheriids is sparse and their exact phylogenetic placement and validity as a distinct family are subjects of ongoing scientific debate and research.

Fossils attributed to ectenotheriids have been found in various locations, suggesting a relatively widespread distribution. However, due to the fragmentary nature of many of these finds, it has been challenging to definitively assign specimens to this family or even to the genus Ectenotherium. The characteristics used to define ectenotheriids often relate to specific features of their cranial and postcranial skeletons, but these can be difficult to interpret without more complete specimens.

The concept of the ectenotheriid family emerged from attempts to classify and understand the diversity within the mosasaur lineage. Some researchers have proposed that certain mosasaur specimens do not fit neatly into established families like the Mosasauridae and therefore warrant their own taxonomic group. However, other paleontologists argue that the evidence is insufficient to support a separate family, suggesting that the specimens might represent variations within existing mosasaur groups or are too poorly preserved to be reliably classified. Consequently, the recognition and definition of ectenotheriid remain tentative within the broader field of paleontology.