A Triassic averostran-line theropod from Switzerland and the early evolution of dinosaurs

Abstract

Although our knowledge of the fossil record of early theropod dinosaurs has greatly improved over the last two decades, very little is known about European taxa because they are largely incomplete. Here we present an exceptionally well-preserved theropod skeleton from the Late Triassic of Europe, pertaining to a new genus and species. The specimen includes a nearly complete skull, two articulated forelimbs and stomach contents. Notatesseraeraptor frickensis gen. et sp. nov. is an early-diverging neotheropod with affinities to Dilophosaurus and Averostra and displays an interesting mixture of character states typically seen either in coelophysids or in dilophosaurids. Based on our phylogenetic analysis, N. frickensis gen. et sp. nov. is considered one of the currently oldest and most basal members of the lineage, leading to Averostra. A monophyletic ‘traditional Coelophysoidea’ including Dilophosaurus is not supported.

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Fig. 1: Skeletal anatomy of N. frickensis gen. et sp. nov.
Fig. 2: Phylogenetic relationships of N. frickensis gen. et sp. nov.

Data availability

All the data supporting the findings of this study are available within the paper and its Supplementary information.

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Acknowledgements

We thank M. Ezcurra, R. Irmis, A. Marsh, S. Nesbitt, A. Pauline-Carabajal, O. Rauhut, L. Rinehart and D. Scott for sharing unpublished photographs of early neotheropod specimens; individuals who permitted the use of their dinosaur silhouettes from PhyloPic; B. Pabst for excellent preparation of the specimen; B. Scheffold for the illustration of the preserved parts of N. frickensis gen. et sp. nov.; and all members of PIMUZ for their support. We also thank the Swiss National Fund (SNF) for supporting this study (project No. 31003A_163346).

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M.Z. and W.B. established the character matrix, scored the taxa for character states and wrote the manuscript. M.Z. carried out the descriptive and comparative work, conducted the phylogenetic analyses, discussed the results and wrote the supplement. W.B. made the Figures.

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Correspondence to Marion Zahner.

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Supplementary Information

Supplementary Tables 1 and 2, Supplementary Fig. 1, Supplementary Discussion, Supplementary References, details on taxa scoring and character list

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Supplementary Data

Nexus file with phylogenetic character matrix

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Zahner, M., Brinkmann, W. A Triassic averostran-line theropod from Switzerland and the early evolution of dinosaurs. Nat Ecol Evol 3, 1146–1152 (2019). https://doi.org/10.1038/s41559-019-0941-z

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