Nearamniote

Nearamniote is a term that has appeared occasionally in paleontological writing and educational materials as an informal label for tetrapods considered to be near the origin of Amniota. It is not recognized as a formal clade in standard taxonomic classifications, and there is no widely accepted diagnostic definition.

In usage, nearamniote is sometimes used to describe early, amniote-like tetrapods that show a mix of basal and derived features, lying close to the split between the lineage leading to Amniota and other early terrestrial tetrapods. Because there is no consensus, the term is ambiguous; different authors may include different taxa under what they call nearamniotes, and some may treat it as synonymous with near-amniotes or as a placeholder for transitional forms.

Traits associated with nearamniotes in informal discussions often include evolving amniote eggs or egg-adaptation features, keratinization of skin, and skeletal changes related to terrestrial life. However, there is no formal diagnosis, and trait sets vary by author.

Taxonomic relationships are likewise unsettled. Nearamniote, if used, would lie near the base of Amniota, potentially including some early eureptiles or closely related groups, but its composition is not fixed and is not widely adopted in cladistic analyses.

See also: Amniota, Eureptilia, Parareptilia, Synapsida, Tetrapodomorpha.