Thursday, July 19, 2018

[Paleontology • 2018] Xiaophis myanmarensis • A mid-Cretaceous Embryonic-to-neonate Snake in Amber from Myanmar

Xiaophis myanmarensis
Xing, Caldwell, Chen, Nydam, Palci, Simões, McKellar, Lee, Liu, Shi, Wang & Bai, 2018

We present the first known fossilized snake embryo/neonate preserved in early Late Cretaceous (Early Cenomanian) amber from Myanmar, which at the time, was an island arc including terranes from Austral Gondwana. This unique and very tiny snake fossil is an articulated postcranial skeleton, which includes posterior precloacal, cloacal, and caudal vertebrae, and details of squamation and body shape; a second specimen preserves a fragment of shed skin interpreted as a snake. Important details of skeletal ontogeny, including the stage at which snake zygosphene-zygantral joints began to form along with the neural arch lamina, are preserved. The vertebrae show similarities to those of fossil Gondwanan snakes, suggesting a dispersal route of Gondwanan faunas to Laurasia. Finally, the new species is the first Mesozoic snake to be found in a forested environment, indicating greater ecological diversity among early snakes than previously thought.

Fig. 1. Overview of amber clast with synchrotron x-ray µCT image of articulated snake skeleton (DIP-S-0907).
 Amber clast with included skeletal material.  

Fig. 4. Light photographs of probable snake shed skin (DIP-V-15104).

Systematic paleontology
 Squamata Oppel, 1811 
Serpentes Linnaeus, 1758 

Xiaophis myanmarensis gen. et sp. nov. 

Holotype: DIP-S-0907 [Dexu Institute of Palaeontology (DIP)], articulated postcranial skeleton (Total Length = 47.5 mm), ~97 vertebrae and ribs, and integument. 

Type locality/horizon: Angbamo site, Tanai Township, Myitkyina District, Kachin Province, Myanmar (98.8 ± 0.6 Ma ago; earliest Cenomanian). 

Etymology: Xiaophis”—Xiao from the Chinese word for “dawn” and in honor of Xiao Jia, the amber specialist who donated the specimens to the DIP, Chaozhou, China; ophis, Greek for snake; and “myanmarensis” in recognition of Myanmar.

An artist's conception of snakes that recently emerged from their eggs, on the floor of the amber-producing forest of Myanmar 99 million years ago. (Yi Liu)

the inferred pattern of light and dark pigmentation on the larger snake, based on a skin fragment found in Burmese amber. (Yi Liu)

Lida Xing, Michael W. Caldwell, Rui Chen, Randall L. Nydam, Alessandro Palci, Tiago R. Simões, Ryan C. McKellar, Michael S. Y. Lee, Ye Liu, Hongliang Shi, Kuan Wang and Ming Bai. 2018. A mid-Cretaceous Embryonic-to-neonate Snake in Amber from Myanmar. Science Advances. 4(7); eaat5042. DOI: 10.1126/sciadv.aat5042

Oldest baby snake fossil, 99 million years old, discovered in Myanmar via @usatoday
First Baby Snake From Dinosaur Era Found in Amber via @NatGeoScience
Rare baby snake fossil found in amber from Age of Dinosaurs


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