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| Eryx linxiaensis Shi, Li, Stidham, Zhang, Jiangzuo, Chen & Ni, 2023 artwork by Qiu-Yang Zheng |
Abstract
The partial skeleton of a fossil snake is described from the Upper Miocene “Liushu” Formation of the Linxia Basin, Gansu Province, in the northeastern Tibetan Plateau of China. Material preserves rare cranial materials of the palatomaxillary arch, in addition to a series of vertebrae, represents a new species of erycine sand boa, Eryx linxiaensis sp. nov., the first fossil record of the superfamily Booidea in China. Combined phylogenetic analysis of osteological, ecological, and molecular data places this new extinct species within the crown clade Eryx as the sister species to the African E. colubrinus, with an average divergence time inferred as ∼8.1 Ma. Eryx linxiaensis sp. nov. differs from the congeneric species by the combination of a series of morphological characters including the slightly dorsoventrally thickened anterior part of the maxilla, eleven maxillary teeth decrease in size posteriorly, more than five pterygoid teeth, relatively elongated middle trunk vertebrae with obvious haemal keel on the centrum, and short neural spine without a thickened dorsal edge. Multiple linear regressions of four vertebral measurements against the body size of extant specimens using an allometric model provide an estimated minimum total body length of c. 694 mm. Estimated species divergence times across the phylogenetic tree support intercontinental dispersals and overall radiation of the clade through the Miocene, potentially tied to increased aridification during parts of the Miocene. Our analysis also suggests that the Eryx crown clade evolved in Africa with at least three intercontinental dispersal events between African and Eurasian continents during the Miocene.
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| Ecology reconstruction of the Miocene erycine snake artwork by Qiu-Yang Zheng |
Jingsong Shi, Qiang Li, Thomas A. Stidham, Chi Zhang, Qigao Jiangzuo, Mo Chen and Xijun Ni. 2023. Evolutionary and Biogeographic Implications of an Erycine Snake (Serpentes, Erycidae, Eryx) from the Upper Miocene of the Linxia Basin, Gansu Province, China. Palaeogeography, Palaeoclimatology, Palaeoecology. 617, 111491. DOI: 10.1016/j.palaeo.2023.111491