Westlothiana

Westlothiana ("animal from West Lothian") is a genus of reptile-like tetrapods that lived about 341 million years ago during the latest part of the Viséan age of the Carboniferous. The genus is known from a single species, Westlothiana lizziae. It is the oldest known uncontroversial tetrapod, closely related to but not an amniote.

==Discovery and naming== The type specimen was discovered in the East Kirkton Limestone at the East Kirkton Quarry, West Lothian, Scotland in 1984. In a study published in 2025 it was suggested that the specimen is around 341 million years old. This specimen was nicknamed "Lizzie the lizard" by fossil hunter Stan Wood, and this name was quickly adopted by other paleontologists and the press. When the specimen was formally named in 1990, it was given the specific name "lizziae" in homage to this nickname. However, despite its similar body shape, Westlothiana is not considered a true lizard. The anatomy of Westlothiana contained a mixture of both "labyrinthodont" and reptilian features, and was originally regarded as the oldest known reptile or amniote.