Huehuecuetzpalli bipedal?

Villaseñor-Amador, Suarez and Cruz 2021
identified bipedalism in the protosquamate, Huehuecuetzpalli (Albian, Early Creteaceous, Fig. 1), as they discuss locomotion types in various Cretaceous lizards. They did not have matching trackways.

Highlights from Villaseñor-Amador, Suarez and Cruz 2021:
The extinct lizard Huehuecuetzpalli mixtecus had a bipedal gait.
The ancestral condition in lizards is inferred to be terrestrial.
The ancestral condition in lizards is inferred with hindlimbs longer than forelimbs.
The bipedal gait was common in lizards since the Lower Cretaceous.

From www.ReptileEvolution.com/huehuecuetzpalli.htm:
“Huehuecuetzpalli could have been an arboreal insectivore considering the extended lengths of its tendril-like toes, the brevity of its torso and the weight reduction in its attenuated palate. The robust hind limb and three sacral vertebrae might suggest a facultative bipedal capability in the manner of similar living lizards and Lacertulus, but the lack of an anterior ilial process argues against that possibility.”

Matching tracks would have been better evidence.
Earlier we talked about bipedalism in Middle Triassic Cosesaurus (Fig. 3), a lepidosaur taxon close to pterosaurs (Peters 2000a, b) that left quadrupedal and bipedal Rotodactylus tracks (Fig. 3 gray tone) left in Early and Middle Triassic strata. Note the anterior process of the ilium + prepubis + 4 sacrals + long neck + long attenuated tail, all traits that enable a bipedal configuration, even while standing still. Note the elongate, locked down coracoids. Those indicate flapping, as in birds and pterosaurs. So Cosesaurus was rarely, if ever, quadrupedal, but often flapping.

References
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods. Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Reynoso V-H 1998. Huehuecuetzpalli mixtecus gen. et sp. nov: a basal squamate (Reptilia) from the Early Cretaceous of Tepexi de Rodríguez, Central México. Philosophical Transactions of the Royal Society, London B 353:477-500.
Shine R and Lambeck R 1989. Ecology of Frillneck liizards, Chlamydosaurus kingii (Agamidae), in tropical Australia. Australian Wildlife Research 16(5):491–500.
Villaseñor-Amador D, SuÃrez NX and Cruz J 2021. Bipedalism in Mexican Albian lizard (squamata) and the locomotion type in other Cretaceous lizards. Journal of South American Earth Sciences 103299 doi: https://doi.org/10.1016/j.jsames.2021.103299
https://www.sciencedirect.com/science/article/abs/pii/S0895981121001462

http://www.reptileevolution.com/huehuecuetzpalli.htm

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