Bergisuchus is an extinct genus of small sebecosuchian mesoeucrocodylian known primarily from the Eocene Messel Pit in Germany. Few fossils of Bergisuchus have been discovered, only a single incomplete snout, a few partial lower jaws and some teeth. Despite being fragmentary, the jaw bones are enough to indicate that Bergisuchus had a short, deep, narrow snout and serrated teeth, quite unlike the broad flat snouts of modern crocodylians.
As with other sebecosuchians, it is likely that Bergisuchus was a fast, terrestrial predator and not an aquatic ambush hunter like modern crocodylians. Its presence in Europe is also unusual, as later sebecosuchians were restricted entirely to South America, and so Bergisuchus indicates the group was once much more widespread in the early Cenozoic.
Bergisuchus was first discovered by Dr. Dietrich Berg from the German Messel Pit in 1966, who originally classified it as an unnamed new species of sebecosuchian with close affinities to Sebecus, notable for being the first sebecosuchian remains to be recognised outside South America.[1] It was named and described two years later in 1968 by German palaeontologist Oskar Kuhn, who named the binomial Bergisuchus dietrichbergi in honour of Dr. Berg and combined it with the Greek suffix suchos for "crocodile". Bergisuchus is known from the holotype snout and lower jaw (HLMD-Me 7003) from the Messel Pit near Darmstadt first reported in 1966, dated to the Mammal Paleogene zone (MP) 11, and an additional incomplete pair of mandibles (GM XVIII-49) from the Geiseltal open-pit coal mine near Halle in the state of Saxony-Anhalt from the slightly younger MP 12.[2] The holotype is stored in the Hessisches Landesmuseum Darmstadt, while the paratype is housed in the Geiseltal Collection of the Center for Natural Science Collections at the Martin Luther University of Halle-Wittenberg, in Germany.[2][3]
In 2015, osteoderms from karst deposits dated to the Middle Eocene in Lissieu, France, were tentatively suggested to belong to Bergisuchus sp., or alternatively to Iberosuchus sp. (another European sebecosuchian). This referral was based on the similarity between the osteoderms and those of Baurusuchus and other sebecosuchians, as the two genera are the only known European sebecosuchians.[4]
Bergisuchus is only represented by the holotype snout and lower jaw (HLMD-Me 7003) and the referred pair of lower jaws (GM XVIII-49), so much of its anatomy is unknown. The snout is tall and laterally compressed, unlike the broad flat snouts of modern crocodylians, with tall nasals that form a raised, sharp midline along the length of the snout. Rossmann and colleagues reconstructed the incomplete premaxillae as tall and steep based on the dimensions of the maxilla, more similar in shape to those of Baurusuchus, Barinasuchus and Bretesuchus than to Sebecus. The premaxilla may also have sloped downwards, similar to that of Bretesuchus.[2] Overall, the snout is relatively short and deep compared to the long, low skull of Sebecus.[5] A deep notch is present between the maxilla and premaxilla to house the large lower canine tooth, along with a prominent bulge of bone above each. Based on the shape of the known snout, it's likely that Bergisuchus had separate nostril openings that faced laterally on the surface, as well as laterally facing eyes, unlike modern crocodylians. Also, it shares with Iberosuchus the unusual presence of a small antorbital fenestra, a feature that's invariably absent in both baurusuchids and sebecids. The surface of the maxilla is profusely sculpted with ridges and grooves, a feature that clearly distinguishes it from Iberosuchus.[2][6]