Cenozoic

Published on January 1st, 2020 | by Elsa Panciroli

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Episode 106: Herpetology

Herpetology is the study of reptiles, amphibians and caecilians. This includes frogs, salamanders, crocodiles, snakes, lizards and tuatara, to name just a few. These cold-blooded tetrapods have an evolutionary history that reaches back to the Carboniferous. For many of these groups, questions remain about their evolutionary relationships and patterns of diversity through major extinction events. New fossil discoveries are helping address some of these outstanding mysteries.

Prof. Susan Evans studies the evolution of ‘herps’ at University College London. She joins us in this episode to give an overview of the field, and the research she is carrying out with colleagues around the world. We explore the elusive origins of crown amphibians, and what recent fieldwork in Scotland could reveal about their emergence in the Jurassic.

Taricha torosa (California newt) from California, USA. Salamanders are abundant on Earth today, and have a good Cenozoic fossil record, but the Mesozoic origins of crown salamanders remain a mystery – one that Evans and colleagues hope to solve. Image: Connor Long CC BY-SA 3.0
The Basiliscus basiliscus (basilisk) from Costa Rica, is known for its ability to run on water. Image: Susan Evans
Valdotriton gracilis, an Early Cretaceous crown group salamander from Las Hoyas, Spain. Described in 1996 by Evans and her colleage Andrew Milner. Image: Susan Evans
A Late Cretaceous polyglyphanodontian lizard called Tianyusaurus, from China. It was described by Mo, Xu and Evans in 2009. Polyglyphanodontids appeared in the E. Cretaceous in North America, and became extinct at the K-Pg boundary. For many lizard groups it isn’t clear how this mass extinction event affected their diversity and range. New fossils from Asia are beginning to fill this gap.
Beelzebufo ampinga (nicknamed the ‘Devil frog’) is a Late Cretaceous frog from Madagascar. Named by Evans et al. in 2008, this 23 cm long amphibian was “a mouth with legs”, and theoretically could have even eaten baby dinosaurs.
Image: Nobu Tamura CC BY 3.0
Prof. Susan Evans on the Isle of Skye during fieldwork in 2004. Ongoing work on Skye by colleagues is recovering new material that is helping uncover the elusive origins of salamanders.

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