Acta Palaeontologica Polonica

Archosaur evidence in the Buntsandstein (Lower Triassic)

Harmut Haubold

Acta Palaeontologica Polonica 28 (1-2), 1983: 123-132

The vertebrate ichnofauna of the German Bunter, primarily horizons of the Hardegsen and Solling Formations, contains archosaur footprints of the genera Brachychirotherium, Chirotherium, Isochirotherium, Rotodactylus, and Synaptichnium. Footprint morphology, trackway pattern and stratigraphic occurrence show that only Synaptichnium and Brachychirotherium correspond with advanced proterosuchians and pseudosuchians. Chirotherium and Isochirotherium are above the pseudosuchian level. Rotodactylus somewhat resembles Lagosuchus. In the Lower Triassic existed at least five lines of fully terrestrially adapted archosaurs. From trackway evidence, the archosaurs of the Lower Triassic show a more complex radiation of terrestial locomotion types than would be expected from the presently known fossil bone record. The footprint fauna of the Buntsandstein may contain thecodonts as well as transitional (non pseudosuchian) forms which may foreshadow later crocodiles, ornithischians, and saurischians.

Key words: footprints, thecodonts, dinosaurs, Middle Buntsandstein, Triassic.

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