Written by National Science Foundation Tuesday, 10 August 2010 10:29
When crocodiles tried to be mammals: the Cretaceous crocodilan Pakasuchus kapilimai, complete with complex, mammal-like dentition and an unusually flexible spine, hunts dragonflies on an ancient Tanzanian floodplain.
Paleontologists scouring a river bank in Tanzania have unearthed a previously unknown crocodile from 105 million-year-old, mid-Cretaceous rock in the Great East African Rift System.
The discovery of the relatively lanky, cat-sized animal with mammal-like teeth and a land-based lifestyle supports a growing consensus that crocodiles were once far more diverse than they are today, dominating ecological niches in the Southern Hemisphere during the Cretaceous Period that were filled in the Northern Hemisphere by early mammals.
An international team of researchers led by Patrick O’Connor of Ohio University describes the new animal in the Aug. 5 issue of Nature.
“At first glance, this croc is trying very hard to be a mammal,” O’Connor said. While numerous character traits show the animal is clearly crocodylian, he added, “A number of characteristics of this new species—including a reduction in its total number of teeth and a dentition specialized into ones similar to canines, premolars and occluding molars—are very similar to features that were critical during the course of mammalian evolution from the Mesozoic into the Cenozoic.”
The researchers have dubbed the new animal Pakasuchus kapilimai. Paka is Ki-Swahili for cat, in reference to the animal’s short, low skull with slicing, molar-like teeth, and souchos is from the ancient Greek for crocodile. The species name kapilimai is in honour of the late professor Saidi Kapilima of the University of Dar es Salaam, a key contributor to the NSF-supported Rukwa Rift Basin Project that led the discovery.