Acanthodactyus erythrura (originally A. lineomaculatus Merre 1820) extant, commonly referred to as a fringe-fingered lizard, is a basal member of the clade that includes Tupinambis and Eolacerta. It was derived from a sister to Liushusaurus.

Distinct from Liushusaurus, the skull of of Acanthodactylus is shorter with larger orbits, as befitting its reduced size. The parietals are flatter and wider, reducing the upper temporal fenestra to specks. The postfrontal also extends posteriorly to fill the former gap. The rostrum is shorter. The naris is larger. The teeth are small, like those in Eolacerta. The retroarticular process angles down. The internal nares are mere slits against the maxillae. The basisphenoid is greatly enlarged.

There are a variety of Acanthodactylus species. The number of presacral vertebrae ranges from 23 to 27. A lumbar region is present of reduced to absent posterior dorsal ribs. Sternum present. Clavicle expanded medially with a large fenestra so the clavicle forms an uninterrupted loop. Interclavicle cruciform. Caudal vertebrae have two pairs of transverse rib. Capable of bipedal locomotion.

Saichangurvel davidsoni (Conrad and Norell 2007; (IGM 3/858; Late Cretaceous) was originally considered a member of the Iguania, but here nests with Acanthodactylus, a lacertid taxon not mentioned in the original text but nesting as a sister to the Iguania and a basal scleroglossan.

Magnuviator ovimonsensis (DeMar et al. 2017; Late Cretaceous) nested with Saichangurvel originally and here. Preserved in the shape of an egg, this taxon has bipedal proportions. The large plate originally identified as a proximal humerus is too large for the small glenoid, so that could be an ilium.

Conrad JL and Norell MA 2007. A complete late Cretaceous Iguanian (Squamata, Reptilia) from the Gobi and Identification of a new iguanian clade. American Novitates 3584:1-47.

DeMar Jr DG, Conrad JL, Head JJ, Varricchio DJ and Wilson GP 2017. A new Late Cretaceous iguanomorph from North America and the origin of New World
Pleurodonta (Squamata, Iguania). Proc. R. Soc. B 284: 20161902.

Merrem B 1820. Versuch cines Systems Amphihien Tentamen Systcmatis Amphibiorum. Marburg, Krieger.

Romer AS 1956. Osteology of the Reptiles University of Chicago Press: 1- 772.

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