A jaw fragment of Obruchevichthys gracilis was recovered from Upper Frasnian (Late Devonian) deposits in Latvia. This specimen, originally identified as a lobe-fin fish, was reclassified as a tetrapod after Per Ahlberg reported that it shared many diagnostic features with the jaw of Elginerpeton, a tetrapod of similar age from Scotland.
Obruchevichthys and Elginerpeton predate the other Late Devonian tetrapods by 5-8 million years. This, and the fact that both tetrapods share several unique features, suggest that they represent a distinct and presumably short-lived radiation that diverged prior to the emergence of other tetrapods.
Associate fauna include placoderms (Bothriolepis), an acanthodian (Devonichus), lungfishes, a porolepiform lobe-fin (Holoptychius) and jawless heterostracans (Psammolepis).
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