The Lacertoidea is a group of
squamate
Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, it ...
reptiles that includes the
Lacertidae
The Lacertidae are the family of the wall lizards, true lizards, or sometimes simply lacertas, which are native to Afro-Eurasia. It is a diverse family with at least 300 species in 39 genera. They represent the dominant group of reptiles found i ...
,
Teiidae
Teiidae is a family of autarchoglossan lizards native to the Americas. Members of this family are generally known as whiptails or racerunners; however, tegus also belong to this family. Teiidae is sister to the Gymnopthalmidae, and both familie ...
,
Gymnophthalmidae
Gymnophthalmidae is a family of lizards with at least 250 species, sometimes known commonly as spectacled lizards or microteiids. They are called "spectacled" because of their transparent lower eyelids, which allow them to still see with closed ...
, and
Amphisbaenia
Amphisbaenia (called amphisbaenians or worm lizards) is a group of usually legless squamates, comprising over 200 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes. A ...
. The finding from molecular phylogenetic studies that the burrowing Amphisbaenia were nested in a clade with the
lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia al ...
forms led Vidal & Hedges (2005) to propose a new name for the group based on shared morphogical characters, Laterata, "referring to the presence of tile-like (squarish or quadrangular, and sometimes raised) scales that form the rings in Amphisbaenia, and are also present ventrally in
Lacertiformata and
Teiformata".
Studies of anatomy have traditionally grouped the lacertoids with
skink
Skinks are lizards belonging to the family Scincidae, a family in the infraorder Scincomorpha. With more than 1,500 described species across 100 different taxonomic genera, the family Scincidae is one of the most diverse families of lizards. S ...
s; however, more recent studies focusing on DNA have placed them as a distinct group of lizards, more closely related to the venomous
Toxicofera
Toxicofera (Greek for "those who bear toxins") is a proposed clade of scaled reptiles (squamates) that includes the Serpentes (snakes), Anguimorpha (monitor lizards, gila monster, and alligator lizards) and Iguania (iguanas, agamas, and cha ...
.
[Wiens, J. J., Hutter, C. R., Mulcahy, D. G., Noonan, B. P., Townsend, T. M., Sites, J. W., & Reeder, T. W. (2012). Resolving the phylogeny of lizards and snakes (Squamata) with extensive sampling of genes and species. Biology Letters, 8(6), 1043-1046.] The relationships of the Amphisbaenia to other lizards have long been a mystery; although superficially snakelike, their anatomy and locomotion is quite distinct from that of snakes, Amphisbaenia have a reduced right lung as opposed to snakes which have their left lung reduced.
[Gans, C. (1978) The characteristics and affinities of the Amphisbaenia. Trans. Zool. Soc. Lond. (1978) 34:347-416.] However, they do not closely resemble any other group of lizards. Recent molecular studies suggest that amphisbaenians are grouped with the Lacertidae, in a group named the Lacertibaenia.
Lacertoids have a wide geographic distribution. The Lacertidae are found throughout Europe and Asia, with a major radiation endemic to Africa. The Teiidae are diverse in South America, but some members of the group occur in southern North America as well. The Amphisbaenia are especially widespread, occurring in North America, Europe, Africa, South America, and the Caribbean. The origins of the group are unclear. The oldest definitive lacertoid is the amphisbaenian ''
Plesiorhineura'', from the early Paleocene of North America. Given that it resembles modern worm lizards, the lacertoids most likely appeared and diversified in the Cretaceous. However,
Berriasian
In the geological timescale, the Berriasian is an age/ stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years a ...
taxon ''
Purbicella
''Purbicella'' is a genus of extinct squamate from the Early Cretaceous of southern England (Lulworth Formation). The type and only species is ''Purbicella ragei'', which was described by Susan E. Evans and colleagues in 2012 for a mostly complet ...
'' may be a lacertoid, and would be the oldest known.
Within the Laterata there are many species listed on IUCN Redlist conservation status. This family listed 5 species extinct, 31 species critically endangered, 53 species endangered, 40 species vulnerable, 53 species near threatened, and 569 species as least concerned.
References
{{Taxonbar, from=Q13518423
Vertebrate superfamilies
Selandian first appearances
Taxa named by Nicolaus Michael Oppel
Extant Selandian first appearances