title: Mid-Cretaceous amber fossils illuminate the past diversity of tropical lizards.
abstract: Modern tropical forests harbor an enormous diversity of squamates, but fossilization in such environments is uncommon and little is known about tropical lizard assemblages of the Mesozoic. We report the oldest lizard assemblage preserved in amber, providing insight into the poorly preserved but potentially diverse mid-Cretaceous paleotropics. Twelve specimens from the Albian-Cenomanian boundary of Myanmar (99 Ma) preserve fine details of soft tissue and osteology, and high-resolution x-ray computed tomography permits detailed comparisons to extant and extinct lizards. The extraordinary preservation allows several specimens to be confidently assigned to groups including stem Gekkota and stem Chamaleonidae. Other taxa are assignable to crown clades on the basis of similar traits. The detailed preservation of osteological and soft tissue characters in these specimens may facilitate their precise phylogenetic placement, making them useful calibration points for molecular divergence time estimates and potential keys for resolving conflicts in higher-order squamate relationships.
authors.affiliation: Department of Biological Sciences, Sam Houston State University, 1900 Avenue I, Lee Drain Building Suite 300, Huntsville, TX 77341, USA.
authors.forename: Juan D
authors.identifier: 0000-0002-5651-0240
authors.initials: JD
authors.lastname: Daza
authors.affiliation: Department of Herpetology, Florida Museum of Natural History, 3215 Hull Road, Gainesville, FL 31611, USA.; Department of Herpetology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA.
authors.forename: Edward L
authors.identifier: 0000-0001-5257-037X
authors.initials: EL
authors.lastname: Stanley
authors.affiliation: Zoologische Staatssammlung München, Münchhausenstraße 21, 81247 Munich, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Wagner
authors.affiliation: Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085, USA.
authors.forename: Aaron M
authors.identifier: 0000-0001-6839-8025
authors.initials: AM
authors.lastname: Bauer
authors.affiliation: Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA.
authors.forename: David A
authors.identifier: 0000-0002-2271-0172
authors.initials: DA
authors.lastname: Grimaldi
mesh_terms: D018647:Amber; D000818:Animals; D044822:Biodiversity; D005580:Fossils; D008116:Lizards / Q000145:classification*; D014057:Tomography, X-Ray Computed; D014329:Tropical Climate
chemical_list: D018647:Amber
keywords: Mesozoic period; fossils; lizards; paleobiology