Please use this identifier to cite or link to this item: https://hdl.handle.net/2440/81849
Citations
Scopus Web of Science® Altmetric
?
?
Type: Journal article
Title: Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara)
Author: Jones, M.
Anderson, C.
Hipsley, C.
Muller, J.
Evans, S.
Schoch, R.
Citation: BMC Evolutionary Biology, 2013; 13(1):1-21
Publisher: BioMed Central Ltd.
Issue Date: 2013
ISSN: 1471-2148
1471-2148
Statement of
Responsibility: 
Marc EH Jones, Cajsa Lisa Anderson, Christy A Hipsley, Johannes Müller, Susan E Evans and Rainer R Schoch
Abstract: Background: Lepidosauria (lizards, snakes, tuatara) is a globally distributed and ecologically important group of over 9,000 reptile species. The earliest fossil records are currently restricted to the Late Triassic and often dated to 227 million years ago (Mya). As these early records include taxa that are relatively derived in their morphology (e.g. Brachyrhinodon), an earlier unknown history of Lepidosauria is implied. However, molecular age estimates for Lepidosauria have been problematic; dates for the most recent common ancestor of all lepidosaurs range between approximately 226 and 289 Mya whereas estimates for crown-group Squamata (lizards and snakes) vary more dramatically: 179 to 294 Mya. This uncertainty restricts inferences regarding the patterns of diversification and evolution of Lepidosauria as a whole. Results: Here we report on a rhynchocephalian fossil from the Middle Triassic of Germany (Vellberg) that represents the oldest known record of a lepidosaur from anywhere in the world. Reliably dated to 238–240 Mya, this material is about 12 million years older than previously known lepidosaur records and is older than some but not all molecular clock estimates for the origin of lepidosaurs. Using RAG1 sequence data from 76 extant taxa and the new fossil specimens two of several calibrations, we estimate that the most recent common ancestor of Lepidosauria lived at least 242 Mya (238–249.5), and crown-group Squamata originated around 193 Mya (176–213). Conclusion: A Early/Middle Triassic date for the origin of Lepidosauria disagrees with previous estimates deep within the Permian and suggests the group evolved as part of the faunal recovery after the end-Permain mass extinction as the climate became more humid. Our origin time for crown-group Squamata coincides with shifts towards warmer climates and dramatic changes in fauna and flora. Most major subclades within Squamata originated in the Cretaceous postdating major continental fragmentation. The Vellberg fossil locality is expected to become an important resource for providing a more balanced picture of the Triassic and for bridging gaps in the fossil record of several other major vertebrate groups.
Keywords: Dating
Fossil
Jurassic
Lepidosauria
Lizards
Molecular
Origin
Squamata
Triassic
Tuatara
Rights: © 2013 Jones et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
DOI: 10.1186/1471-2148-13-208
Appears in Collections:Aurora harvest 4
Earth and Environmental Sciences publications

Files in This Item:
File Description SizeFormat 
hdl_81849.pdfPublished version3.72 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.