Ancient Toothy Lizard Is The First Of Its Kind From South America
Aug 26, 2015 @ 4:03 AM 446 views
Ancient Toothy Lizard Is The First Of Its Kind From South America
Shaena Montanari ,
Contributor
Although it may look different now with its subtropical climate, 80 million years ago, Paraná in southern Brazil was an arid desert that hosted a diverse array of vertebrates ranging from dinosaurs to pterosaurs, and now as paleontologists have discovered, also an unexpected type of lizard. Published today in Nature Communications by lead author Tiago Simões from the University of Alberta and an international team of paleontologists, a new genus and species of an iguana relative has been discovered in Brazil and it has some surprising teeth.
Modern iguanians (lizards such as iguanas and agamids) are one of the most diverse groups of lizards on the planet with over 1700 species. Iguanians are divided into two groups based on how they have their teeth attached to their jaws: acrodont and pleurodont. Acrodont iguanians have no root or socket to their teeth and they are attached to the top of the jaw. Pleurodont iguanians also do not have roots to their teeth, but they attach on the inside portion of the jaw. Interestingly, iguanians with acrodont dentition are primarily restricted to an Old World distribution while pleurodonts are found only in the New World. But now it appears this new fossil found in Brazil breaks this convention.
Gueragama sulamerica, the “ancient agama from South America”, discovered in Cruzeiro do Oeste in Paraná, is the oldest known New World acrodont iguanian. This means that at one point, lizards with this type of dentition had a worldwide distribution and spread across the ancient southern supercontinent Gondwana. This raises new questions about the biogeography and evolution of these two groups—if only pleurodonts live in the Americas today, what happened to the acrodonts now known to have been there since at least the Late Cretaceous? Lead author Tiago Simões explains: “It becomes clear acrodontan iguanians migrated throughout southern continents much earlier than previously thought (actually reaching regions where they do not inhabit today) by the order of tens of millions of years.”
This finding expands the mostly unknown fossil diversity of South American lizards. Even the pterosaurs in this region were discovered only recently, and Simões thinks there are still many more secrets of the Brazilian Cretaceous to be revealed: “We have only hit the tip of the iceberg, and there is probably a lot more interesting species that will be found there in the years to come as field work continues. Hopefully, more material of Gueragama too, which will allow us to understand more about the morphology of stem acrodontans.”
More:
http://www.forbes.com/sites/shaenamontanari/2015/08/26/ancient-toothy-lizard-is-the-first-of-its-kind-from-south-america/
Science:
http://www.democraticunderground.com/122841760
