Friday, June 15, 2018

[Paleontology • 2018] Electrorana limoae • The Earliest Direct Evidence of Frogs in Wet Tropical Forests from Cretaceous Burmese Amber


Electrorana limoae
Xing, Stanley, Bai & Blackburn, 2018

Illustration: Damir G. Martin || nature.com 

Abstract
Frogs are a familiar and diverse component of tropical forests around the world. Yet there is little direct evidence from the fossil record for the antiquity of this association. We describe four fossil frog specimens from mid-Cretaceous (~99 mya) amber deposits from Kachin State, Myanmar for which the associated fauna provides rich paleoenvironmental context. Microcomputed tomographic analysis provides detailed three-dimensional anatomy for these small frogs, which is generally unavailable for articulated anurans in the Mesozoic. These crown-group anuran specimens provide the earliest direct evidence for anurans in a wet tropical forest. Based on a distinct combination of skeletal characters, at least one specimen has clear similarities to living alytoid frogs as well as several Mesozoic taxa known from the Jehol Biota in China. Whereas many Mesozoic frogs are from seasonal and mesic paleoenvironments, these fossils provide the earliest direct evidence of anurans in wet tropical forests.


   

Systematic Paleontology
Order Anura Fischer von Waldheim, 1813.
? Alytoidea Fitzinger, 1843.

Family undetermined.

Genus Electrorana gen. nov.  
Type species Electrorana limoae sp. nov.;  

Etymology: Electrorana is feminine and derives from the Latin electrum (amber) and rana (frog). The specific epithet, limoae, is a matronym in the genitive singular for Mrs. Mo Li, who purchased and provided these specimens for study.

Type locality and horizon: These amber-preserved specimens were acquired in the area of Angbamo in Kachin Province of northern Myanmar in August 2015. Burmese amber derives from late Albian–Cenomanian deposits (approx. 105–95 mya). Dating of zircons from the volcaniclastic matrix in these deposits provides an age of 98.8 ± 0.6 million years.

Figure 1 Photograph images of four fossil frog specimens referred to Electrorana,
including the holotype (A; DIP-L-0826) and three additional specimens (B: DIP-V-16119; C: DIP-V-16127; D: DIP-V-16121).
Specimens in (B) and (D) are presented with two views of the amber specimen and the oval in (D) indicates the presence of the anuran specimen.
Scale bars equal 5 mm.


Illustration: Damir G. Martin 


Lida Xing, Edward L. Stanley, Ming Bai and David C. Blackburn. 2018. The Earliest Direct Evidence of Frogs in Wet Tropical Forests from Cretaceous Burmese Amber.  Scientific Reports.   8, Article number: 8770 nature.com/articles/s41598-018-26848-w

Amber fossils provide oldest evidence of frogs in wet, tropical forests  eurekalert.org/e/8W6k via @EurekAlert
World's Oldest Rain Forest Frogs Found in Amber  on.natgeo.com/2HLDO6I   @NatGeo
Amber fossils provide oldest evidence of frogs in wet, tropical forests  news.ufl.edu/articles/2018/06/amber-fossils-provide-oldest-evidence-of-frogs-in-wet-tropical-forests.php

  

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