Acrodonta are a subclade of

iguania Iguania is an infraorder of squamate reptiles that includes iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids. Using morphological features as a guide to evolutionary relationships, the Iguania are believed ...

squamate Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest Order (biology), order of reptiles; most members of which are commonly known as Lizard, lizards, with the group also including Snake, snakes. With over 11,991 species, it i ...

s consisting almost entirely of Old World taxa. Extant representation include the families Chamaeleonidae (chameleons) and

Agamidae Agamidae is a family containing 582 species in 64 genera of iguanian lizards indigenous to Africa, Asia, Australia, and a few locations in Southern Europe. Many species are commonly called dragons or dragon lizards. Overview Phylogenetically ...

(dragon lizards), with at least over 500 species described. A fossil genus, '' Gueragama'', was found in

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

making it the only known American representative of the group. The group is eponymously named from their acrodont dentition, whereby the teeth are consolidated with the summit of the

alveolar ridge The alveolar process () is the portion of bone containing the tooth sockets on the jaw bones (in humans, the maxilla and the mandible). The alveolar process is covered by gums within the mouth, terminating roughly along the line of the mandib ...

of the jaw without sockets. There are, however, other animals that have acrodont dentition such as

tuatara The tuatara (''Sphenodon punctatus'') is a species of reptile endemic to New Zealand. Despite its close resemblance to lizards, it is actually the only extant member of a distinct lineage, the previously highly diverse order Rhynchocephal ...

Systematics

Usually acrodonts are divided into two families Chamaeleonidae and Agamidae, there are a few studies that suggest chameleons are nested within Agamidae. In order to maintain the familial status of Chamaeleonidae some authors suggested placing the clades Uromastycinae and Leiolepidinae in a third family Leiolepididae. However a majority of papers concerning acrodont phylogenetics support the traditional dichotomy of the group. Below is the phylogeny of the acrodont lineages after Pyron ''et al.'' (2013): The extinct Arretosauridae (

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

iguanians from Central Asia) are also sometimes classified in Acrodonta. However, other studies instead suggest it to be a sister group to the Crotaphytidae in Pleurodonta.

References

{{Taxonbar, from=Q60790273 Iguanomorpha Taxa named by Edward Drinker Cope