Retinosaurus hkamtiensis (Cernansky et al. 2021; Early Cretaceous; GRS 29689) is a tiny lizard found in Burmese amber and considered a juvenile. Here it nests with Eichstaettisaurus, a snake ancestor. Tiny taxa, like this, typically nest at the base of new clades. Outgroups include the last common ancestor of gekkos + snakes, Tchingisaurus.

Eichstaettisaurus schroederi (Broili 1938, Hoffstetter 1953, Kuhn 1958) Late Jurassic, ~150 mya, ~10 cm in length was originally considered another Ardeosaurus, but has several distinct characters (note the feet). It is a snake ancestor basal to Jucaraseps, Pachyrhachis and other extant terrestrial snakes. Originally and traditionally it was considered a relative of Gekko, but nests near the base of geckos, skinks, varanids and snake ancestors.

Eichstaettisaurus gouldi (Evans et al. 2004) Early Cretaceous, has a longer torso, shorter legs and a very snake-like palate, nesting it closer to snakes than either of these two taxa. Bipedal Cretaceous lizard tracks (Lee et al. 2018) are best matched to Eichstattisaurus.

Bolet A and Evans SE 2012. A tiny lizard (Lepidosauria, Squamata) from the lower Cretaceous of Spain. Palaeontology 55:491-500.

Broili F 1938. Ein neuer fund von ?Ardeosaurus H. von Meyer. Sitzungs− berichte der Bayerischen Akademie der Wissenschaften, München 1938: 97–114.

Caldwell M, Nydam R, Palci A and Apesteguía S 2014. The oldest known fossil snakes: a tempera range extension of 70 million years. Journal of Vertebrate Paleontology abstracts.

Cernansky A et al. (9 co-authors) 2021. A new Early Cretaceous lizard in Myanmar amber with exceptionally preserved integument. Research Square Scientific Reports 12(1):1660. https://doi.org/10.21203/rs.3.rs-952564/v1

Evans SE, Raia P and Barbera C 2004. New lizards and rhynchocephalians from the Lower Cretaceous of southern Italy. Acta Palaeontologica Polonica 49:393-408.

Hoffstetter R 1953. Les Sauriens anté−crétacés. Bulletin de la Museum Nationale d’Histoire Naturelle 25: 345–352.

Kuhn O 1958. Ein neuer lacertilier aus dem fränkischen Lithographie−schiefer. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte 1958: 437–440.

Lee H-J, Lee Y-N, Fiorillo AR & LÃ J-C 2018. Lizards ran bipedally 110 million years ago. Scientific Reports 8: 2617. doi:10.1038/s41598-018-20809-z
https://www.nature.com/articles/s41598-018-20809-z

Meyer H von 1860. Zur Fauna der Vorwelt. Reptilien aus dem lithographischen Schiefer des Jura in Deutschland mit Franchreich. Frankfurt-am-Main.

wiki/Eichstaetisaurus
wiki/Retinosaurus