A near-tetrapod from the Baltic Middle Devonian

• The tetrapodomorph sarcopterygian Livoniana multidentata gen. et sp. nov, is described on the basis of lower jaw fragments from the Middle Devonian (late Givetian) of Latvia and Estonia. It possesses a suite of derived characters previously only known fromtetrapods, which first appear in the late Devonian (late Frasnian), and a phylogenetic analysis places it on the internode between Panderichthys and the base of the Tetrapoda.The analysis also reveals that the 'Elpistostegalia' are paraphyletic to Tetrapoda, with Elpistostege closer to tetrapods than is Panderichthys. Owing to incompleteness of thematerial, there is almost no overlap between the data sets for Elpistostege and Livoniana;the analysis places the two genera in an unresolved trichotomy. In addition to the tetrapodfeatures, Livoniana has a strikingly autapomorphic dentary dentition comprising multiple tooth rows. It thus provides evidence both for the unexpectedly early evolution of tetrapodcharacteristics and for morphological radiation around the fish-tetrapod transition.

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