However, it has recently been suggested that the anapsid condition of the turtle skull may not be a primitive character reflecting anapsid descent, but rather a case of convergent evolution. More recent phylogenetic studies with this in mind have placed turtles firmly within diapsids, slightly closer to Squamata than to Archosauria. All molecular studies have strongly upheld this new phylogeny, though some place turtles closer to Archosauria. Re-analysis of prior phylogenies that affirmed an anapsid ancestry suggests that their inclusion of turtles within Anapsida was due to both the starting assumption that they were anapsid (most prior phylogenies concerned what sort of anapsid they were) and also due to insufficiently broad sampling of fossil and extant taxa for construction of the cladogram. While the issue is far from resolved, most scientists now lean towards a Diapsid origin for turtles.













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Images 1 Through 12 Come From The US Fish & Wildlife Service
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