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Data from: The amphibamiform Nanobamus macrorhinus from the early Permian of Texas


Gee, Bryan; Reisz, Robert (2020), Data from: The amphibamiform Nanobamus macrorhinus from the early Permian of Texas, Dryad, Dataset,


Nanobamus macrorhinus is a small amphibamiform temnospondyl from the early Permian Arroyo Formation of Texas. It is most readily characterized by an elongate and partially subdivided naris. This condition is superficially reminiscent of that seen in the coeval trematopids, the group to which N. macrorhinus was originally referred to under an interpretation of the holotype as a larval form. This was discounted by later workers, but the amphibamiform affinities of the specimen were not formalized until recently. The specimen has never been described in the context of its amphibamiform affinities and remains poorly characterized, never having been sampled in a phylogenetic analysis. Here we present a complete, updated osteological description of N. macrorhinus, including an improved characterization of its unique mosaic of plesiomorphic and apomorphic features and clarification of the taxon’s autapomorphies. Our analysis of the taxon’s phylogenetic position within Amphibamiformes shows that N. macrorhinus is recovered as diverging after basal amphibamiforms such the micropholids and before derived amphibamiforms such as the amphibamids. This is supported by the unique mixture of retained plesiomorphies such as non-foreshortened postparietals and an oval choana and apomorphies such as a narrow interorbital region and slender palatal rami of the pterygoid. These results reflect the complexity of terrestrial amphibamiform diversity and provide further insight into the evolutionary history of the lissamphibian stem in terrestrial environments.

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North America