Mittilineaursidae

Mittilineaursidae is a fossil vertebrate family name that appears in a small body of paleontological literature. The taxon’s validity and precise composition are uncertain, and it has been treated by some authors as a distinct family within a broader clade of early reptiles or reptile-like vertebrates, while others regard it as a nomen dubium or a junior synonym of a better-supported group. Because original material is fragmentary and diagnostic features are not consistently described, there is no universally accepted diagnosis or set of autapomorphies for Mittilineaursidae.

Fossil evidence attributed to Mittilineaursidae is limited to a handful of fragmentary remains recovered from a few localities. As a result, the temporal and geographic range of the group is poorly constrained and varies among studies. The fossils have been variably placed within early archosauromorphs, diapsids, or other basal reptile lineages, reflecting broader uncertainties about early reptile diversification and relationships.

The etymology of the name follows standard zoological conventions, deriving from the associated genus stem with the suffix -idae indicating a family. Due to the unsettled status of the taxon, many contemporary databases list Mittilineaursidae as unresolved or unaccepted, and researchers emphasize caution when interpreting its placement in vertebrate phylogeny.

See also: List of prehistoric reptile families; Taxonomy of Paleozoic vertebrates.

References: Given the lack of consensus, consult the original description and subsequent discussions for differing viewpoints; prefer primary sources when evaluating the current status of Mittilineaursidae.