Original paper

Odontological and osteological investigations on propalaeotheriids (Mammalia, Equidae) from the Eocene Geiseltal Fossillagerstätte (Central Germany) - a full range of extraordinary phenomena

Hellmund, Meinolf


The high amount of dentitions of propalaeotheres from the Geiseltal Fossillagerstiitte, especially from the vertebrate site “XIV“ in the “Unterkohle“ (MP 11), allows a detailed insight into the various phenomena how teeth may develop and display within their life time. These are wear, loss or tooth replacement, irregular insertions, supernumerary teeth and even mechanical post-mortem wear through mechanical polishing. Pathological structures in bones also rarely occur. The succession of replacing the milk dentition step by step and the eruption of the permanent teeth are demonstrated in the fossil record within a lot of different individual ages. It is striking that nothing is happening occasionally here, but in a definite order. Therefore we can distinguish and establish a descriptive “classification“ in the sense of “... older or younger as ... “ or “juvenile, subadult (“transitional“), adult and senile“. This descriptive method makes sense in palaeontology, however, annualising the classification is impossible. In order to document irregularities in dentitions as discussed here, it is highly necessary and even indispensable, to excavate a “quantum satis“ of specimens for comparison from one and the same locality. The vertebrate site “XIV“ contributed numerous equid fossils over a time span of at least four years of excavation. Due to that, a highly interesting result is verified for the maxillaries and mandibles of propalaeotheriids of the Geiseltal Fossillagerstiitte. As in other rapidly growing mammals, all three molars of the propalaeotheres usually erupt before their deciduous teeth were replaced, a procedure which is called “Schultz's rule“.


eocenegeiseltal fossillagerstiittepropalaeotheriumeurohippusdentitionweartooth anomalies“schultz's rule“