Chamaeleontiformes

Chamaeleontiformes is a hypothesized clade (evolutionary grouping) of iguanian lizards defined as all taxa sharing a more recent common ancestor with Chamaeleo chamaeleon (the common chamaeleon) than with Hoplocercus spinosus (the Brazilian spiny-tailed lizard), Polychrus marmoratus (bush lizard), or Iguana iguana (green iguana). It was named by paleontologist Jack Conrad in 2008 to describe a clade recovered in his phylogenetic analysis that included the extinct genus Isodontosaurus, the extinct family Priscagamidae, and the living clade Acrodonta, which includes agamids and chameleons.^[1] It is a stem-based taxon and one of two major clades within Iguania, the other being Pleurodonta. Below is a cladogram from Daza et al. (2012) showing this phylogeny:^[2]

Chamaeleontiformes Temporal range: Early Jurassic- present, 190–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Common chameleon, Chamaeleo chamaeleon
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Iguania
Clade:	Chamaeleontiformes Conrad, 2008
Subgroups
†Isodontosaurus? †Priscagamidae Acrodonta

Iguanomorpha	†Hoyalacerta sanzi †Huehuecuetzpalli mixtecus †Pristiguana brasiliensis Iguania Chamaeleontiformes †Priscagamidae Acrodonta Iguanoidea (=Pleurodonta)

Other analyses place Priscagamidae outside Iguania altogether, resulting in a Chamaeleontiformes that only includes Isodontosaurus and Acrodonta. Below is a cladogram from Conrad (2015) with this phylogeny:^[3]

Iguanomorpha	†Priscagamidae †Gobiguania Iguania Chamaeleontiformes †Isodontosaurus gracilis Acrodonta Pleurodonta

References

1. Conrad, J. L. (2008). "Phylogeny and Systematics of Squamata (Reptilia) Based on Morphology". Bulletin of the American Museum of Natural History. 310: 1–182. doi:10.1206/310.1. hdl:2246/5915. S2CID 85271610.
2. Daza, J. D.; Abdala, V.; Arias, J. S.; García-López, D.; Ortiz, P. (2012). "Cladistic Analysis of Iguania and a Fossil Lizard from the Late Pliocene of Northwestern Argentina". Journal of Herpetology. 46: 104–119. doi:10.1670/10-112. hdl:11336/61054. S2CID 85405843.
3. Conrad, Jack L. (2015). "A New Eocene Casquehead Lizard (Reptilia, Corytophanidae) from North America". PLOS ONE. 10 (7): e0127900. Bibcode:2015PLoSO..1027900C. doi:10.1371/journal.pone.0127900. PMC 4489568. PMID 26131767.