Crawford et al., 2015 
Archelosauria is a clade grouping turtles and archosaurs (birds and crocodilians) and their fossil relatives. Multiple sequence alignments of DNA and protein sequences and phylogenetic inferences showed that chelonians are the sister group to birds and crocodilians. Morever, there are about 1000 ultra-conserved elements in their genome that are unique to turtles and archosaurs, but which are not found in lepidosaurs (tuatara, lizards and snakes). Other genome-wide analysis also supports this grouping.
The clade name Archelosauria was coined in 2015 to evoke its two subclades, the Archosauria and the Chelonia.
Archelosauria is a group used to unite archosaurs with turtles. It was found that Archelosauria was grouped within Sauria, as the sister branch to lizards and Sphenodon. Below is the phylogeny from Crawford et al., showing interrelationships of Testudines at family level down to Durocryptodira.