Name Meaning: Northern Crocodile
Geologic Era: Late Cretaceous to Eocene
Location Found: Montana
Estimated Range: Canada and American Northwest
Size: Up to 2.8 meters in length
Borealosuchus was one of the survivors of the Cretaceous-Tertiary extinction that wiped out dinosaurs and many other reptiles. Borealosuchus and its kin hung on until well into the Eocene era. Borealosuchus was a mid-sized crocodilian, generally not more than 10 feet in length. It would have been able to prey on small to mid sized vertebrates, including smaller dinosaurs. It would probably fit in the same ecological niche as modern caimans. Caimans are predators in their own right, but far from the largest carnivores in their environment.
Until rather recently, Borealosuchus was called Leidyosuchus. Such renaming happens from time to time. Prior to the renaming, Leidyosuchus was applied to many similar sized crocodiles found in that area. As analysis techniques improved, differences began to emerge between some of the Leidyosuchus species. Several were reassigned to Borealosuchus, while others were deemed too fragmented to accurately assign to a species. Our tail vertebra may be from one of the few still assigned to Leidyosuchus, but the odds are against it. I would not necessarily consider Leidyosuchus to have been as wastebasket taxon, but it certainly approached that status before the reassigning.
Many crocodilians operate as ambush predators. Generally, they will wait below the surface of the water until prey comes close enough to strike. If the attack is successful, the prey is dragged into to the water to drown. Crocodilians usually will not chase their prey on land if it happens to escape, as they cannot move as quickly or easily on land as they can in the water. They best move for an escaping prey item would be to run in a zig-zag pattern away from the water’s edge. On the off chance the crocodilian did decide to pursue, they cannot make turns very well, and a series of fast directional changes would probably ensure the prey’s escape. In a straight line, however, crocodilians can be surprisingly fast.
Skeleton: “Borealosuchus wilsoni 1” by Smokeybjb – Own work. Licensed under CC BY-SA 3.0 via Commons – https://commons.wikimedia.org/wiki/File:Borealosuchus_wilsoni_1.jpg#/media/File:Borealosuchus_wilsoni_1.jpg
Broad Snouted Caiman: “Jacare de papo amarelo zoo” by Miguelrangeljr – Own work. Licensed under CC BY 3.0 via Commons – https://commons.wikimedia.org/wiki/File:Jacare_de_papo_amarelo_zoo.jpg#/media/File:Jacare_de_papo_amarelo_zoo.jpg