Specimen summary
Tooth crown of an indeterminate archosauromorph from the Middle Triassic of Upper Silesia, Poland. Serrated, ziphodont morphology consistent with terrestrial or semi-aquatic predatory reptiles.
Description
Archosauriformes indet.
Middle Triassic, ?Lower Muschelkalk (Anisian)
Upper Silesia, Poland
The tooth crown length is approximately 10mm. The tooth is flattened transversely, with one side hidden in the matrix. The crown width at its widest point is approximately 6mm.
The tooth crown clearly recurved, of the ziphodont morphotype. Carinae are visible on the edges, both mesial and distal (bisseration). Serrations are developed along the entire length of both carinae. Fine denticles are gently rounded (see photo).
The overall morphology and the presence of serrated carinae are consistent with the dentition of terrestrial or semi-aquatic predators belonging to the Archosauriformes clade.
The tooth is likely allochthonous. The presence of a terrestrial predator tooth in marine sediments likely indicates the transport of material by rivers (fluvial input) or coastal processes.
Stratigraphy note
I pointed to the Lower Muschelkalk, but… This is where the Gogolin Beds and Röt layers meet, with a large zone marked as “Triassic” between them. Furthermore, the terrain has been transformed by glaciers and agriculture, and this is surface find.
My assumption is based on the presence of individual crinoids in the limestone matrix, whose presesence is usually associated with fully marine conditions where uppermost Röt is usually interpreted as lagoon/sebkha.
References:
- Borsuk, M., & Evans, S. E. (b.d.). CRANIAL AND MANDIBULAR OSTEOLOGY OF THE EARLY TRIASSIC ARCHOSAURIFORM OSMOLSKINA CZATKOWICENSIS FROM POLAND.
- Surmik, D., & Brachaniec, T. (2013). The large superpredators’ teeth from Middle Triassic of Poland. Contemporary Trends in Geoscience, 2(1), 91–94. https://doi.org/10.2478/ctg-2014-0013
- Skawiński, T., Ziegler, M., Czepiński, Ł., Szermański, M., Tałanda, M., Surmik, D., & Niedźwiedzki, G. (2017). A re-evaluation of the historical ‘dinosaur’ remains from the Middle-Upper Triassic of Poland. Historical Biology, 29(4), 442–472. https://doi.org/10.1080/08912963.2016.1188385
- Hoffman, D. K., Edwards, H. R., Barrett, P. M., & Nesbitt, S. J. (2019). Reconstructing the archosaur radiation using a Middle Triassic archosauriform tooth assemblage from Tanzania. PeerJ, 7, e7970. https://doi.org/10.7717/peerj.7970
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