Lacertibaenia
Lacertibaenia is a clade of squamate reptiles that unites the worm lizards with the true lizards. The clade was named by Vidal & Hedges, who recovered the group from analyses of nine nuclear protein-coding genes within their broader clade Laterata. Subsequent molecular datasets with broader gene and taxon sampling have repeatedly recovered amphisbaenians as sister to lacertids, corroborating the monophyly of Lacertibaenia. A 2024 satellite-DNA study further supported Lacertibaenia as a coherent lineage.
Evolutionary history
An important fossil relevant to Lacertibaenia is the Messel fossil Cryptolacerta hassiaca, which Müller et al. interpreted as shedding light on amphisbaenian origins and supporting a close relationship with lacertids. Additional paleontological work has proposed Late Cretaceous stem-amphisbaenians and explored trait evolution associated with fossoriality in worm lizards.Taxonomy and systematics
Vidal & Hedges erected Lacertibaenia within the larger clade Laterata, which they subdivided as Teiformata and Lacertibaenia. Their classification was refined in a later synthesis focusing on squamate molecular evolution and divergence times, and has been widely adopted in subsequent molecular phylogenies of Squamata.Within Laterata/Lacertoidea, Teiformata is usually recovered as the sister group to Lacertibaenia. Some large-scale morphology-focused matrices have instead placed amphisbaenians in alternative positions, highlighting persistent conflict between data types and character sampling strategies.