Prehistoric Groundhog keeps scientists guessing
A paper published in Nature this week has unveiled only the 3rd mammal discovered in the cretaceous southern hemisphere. Our knowledge of mammalian evolution in the North is well-documented but the south is an unknown entity. Occupied mostly by dinosaurs there has been little evidence of mammals unearthed. A complete and well-preserved cranium of a prehistoric groundhog, Vintana of the Gondwantheria group, may change all that.
Reconstructions suggest a 10kg animal, with a bizarre mix of huge eyes, large cheeks sitting on high prominent cheekbones and a downward pointing face. These gave the rodent a keen sense of hearing and smell. This mix of features whilst in part drawn from ancestry in Gondwana (a prehistoric southerly supercontinent) is due to it’s isolated evolution on the separated Indo-Madagascar. This isolation also helped developed species such as predatory frogs, herbivorous crocodiles and blind snakes.
Vintana offers clues to the early development of mammals in the cretaceous but it’s bizarre morphology is likely to keep scientists guessing for sometime to come. Further discoveries on the Gondwana mainland are likely to offer better clues into how mammals came to dominate the south.