Mesorhinosuchus fraasi ( Jaekel, 1910 )

Sues, Hans-Dieter & Schoch, Rainer R., 2025, Synopsis of the Triassic reptiles from Germany, Fossil Record 28 (2), pp. 411-483 : 411-483

Mesorhinosuchus fraasi ( Jaekel, 1910)

Holotype.

Originally housed in GPG, destroyed during World War II. Incomplete cranium lacking the premaxillae and much of the right side of the posterior region.

Type locality.

According to the specimen label cited by Jaekel (1910), the fossil was collected near Bernburg an der Saale, Saxony-Anhalt.

Type horizon.

Jaekel (1910) argued that the specimen came from the lowermost portion of the Middle Buntsandstein Subgroup, which is Early Triassic (Olenekian: Spathian) in age.

Diagnosis.

As the holotype and only known specimen is lost it is not possible to develop a modern diagnosis.

Comments.

Jaekel (1910) described an incomplete cranium, which had previously been identified as the temnospondyl amphibian Trematosaurus brauni and reinterpreted it as a phytosaur. He proposed the binomen Mesorhinus fraasi for its reception. The genus name was already preoccupied and thus was replaced by Mesorhinosuchus ( Kuhn 1961) . Based on Jaekel’s (1910: fig. 2) photograph of the dorsal surface of the cranium, we agree with Gregory (1962) and Chatterjee (1978) that the specimen closely resembles skulls of “ Paleorhinus ” (= Parasuchus ). The label associated with the specimen stated that it was found at Bernburg. Jaekel compared its matrix with Buntsandstein sediments from the Bernburg region and was satisfied that he had confirmed the locality information on the specimen label. Since then, however, the considerable temporal gap between Mesorhinosuchus fraasi and the oldest known phytosaur, Diandongosuchus fuyuanensis from the Middle Triassic (Ladinian) of Yunnan ( China) ( Stocker et al. 2017), has led most researchers to question its provenance. Due to loss of the holotype and the lack of additional material it is impossible to resolve this issue.

References.

Jaekel (1910), Kuhn (1961), Gregory (1962), Chatterjee (1978).