Yabeinosaurus

Yabeinosaurus is an extinct genus of lizard from the Early Cretaceous Jehol Group of northeastern China. The type species Yabeinosaurus tenuis is known from many well-preserved skeletons belonging to both juvenile and adult individuals. For about 60 years Yabeinosaurus was known only from juvenile specimens, leading scientists to believe that it was a small lizard with weakly developed bones. Because of this, it was thought to be closely related to geckos. Larger specimens up to 35 centimetres (14 in)

Yabeinosaurus
Temporal range: Early Cretaceous
Fossil of Y. tenuis, Beijing Museum of Natural History
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Informal group: Scleroglossa (?)
Genus: †Yabeinosaurus
Endo and Shikama, 1942
Type species
†Yabeinosaurus tenuis
Endo and Shikama, 1942
IVPP V18005, a specimen preserved with over 15 embryos inside it, Paleozoological Museum of China

long were first described in 2005, showing that Yabeinosaurus was a relatively large lizard when fully grown. Recent phylogenetic analyses indicate that Yabeinosaurus is not closely related to geckos but rather a very basal ("primitive") lizard close to the split between Iguania and Scleroglossa, one of the earliest divergences in the evolutionary history of lizards. Whether or not it lies outside this split or within Scleroglossa is uncertain.[1]

Fossil of Y. tenuis in the Beijing Museum of Natural History

In 2011 a fossil of Yabeinosaurus was discovered with 15 well-developed embryos inside it, making it the oldest fossil of a pregnant, viviparous (live-bearing) lizard yet discovered.[2][3]

References
  1. Evans, S. E.; Wang, Y.; Li, C. (2005). "The early Cretaceous lizard genusYabeinosaurusfrom China: Resolving an enigma". Journal of Systematic Palaeontology. 3 (4): 319. doi:10.1017/S1477201905001641.
  2. Wang, Y.; Evans, S. E. (2011). "A gravid lizard from the Cretaceous of China and the early history of squamate viviparity". Naturwissenschaften. 98 (9): 739–743. Bibcode:2011NW.....98..739W. doi:10.1007/s00114-011-0820-1. PMID 21766177.
  3. Fossil 'is first pregnant lizard', BBC Nature, 21 July 2011


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