Lungfish from the Lueders Formation (Lower Permian, Texas) and the Gnathorhiza-lepidosirenid ancestry questioned

Well preserved tooth plates, vomerine teeth, and lower jaws of the lungfish Gnathorhiza, collected from the Lueders and Arroyo Formations [in Baylor County, north-central Texas], are in close accord with those of other late Paleozoic dipnoans, particularly Sagenodus, and with the recent Epiceratodus. The similarities suggest that the two extinct genera were herbivorous, as is Epiceratodus. The resemblance between the tooth plates of Gnathorhiza and the recent lepidosirenids is viewed as superficial and of little value as an indicator of relationship. Dentition of the living lepidosirenids has undergone extensive remodelling away from the typical dipnoan condition, suiting them for an actively predaceous existence. Sagenodus is also recorded from the Lueders Formation; a spatial, ecological separation may have existed between it and Gnathorhiza.

This record provided courtesy of AGI/GeoRef.