Your Daily Fossil

Dec 6

Pakasuchus - the cat-like crocodile

When: Middle Cretaceous ~ 105 million years ago

Where: Tanzania, Africa

What: A Notosuchia Crocodylomorpha. Crocodiles today are all aquatic, sprawling, and fairly large (the smallest is about 5ft/1.5 meters long). However, fossil crocodiles occupied many niches and had a wide range of body types not seen in living species. A great example is Pakasuchus. This small and agile croc was completely terrestrial and only about the size of a house cat!  Its dentition was also very different from modern crocs. Living crocodiles are all homodont, all of their teeth are fairly similar cones, but Pakasuchus was heterodont like mammals. Its had not only cone like teeth, but also some teeth well suited for shearing and others for crushing and grinding. 

Pakasuchus and the rest of the notosuchians, most of which are cool enough they will be individual highlighted in future posts, are excellent examples of how the fossil record can show us lost diversity within clades that today are fairly homogenous. Crocodile line archosaurs (the clade containing crocs and dinos) were hit hard by the end Cretaceous extinction, with only modern forms surviving.  Its probable Pakasuchus or animals much like it survived to the end of the Cretaceous, even though we only have a handful of fossils from the mid-Cretaceous. Careful inspection of fossil material for distinctive Pakasuchus teeth needs to happen, and will hopefully increase it’s temporal and geographic range.