Anapsids [1] ( lat. Anapsida ) are amniotes , the skull of which has no temporal windows [2] . They are one of two subclasses of reptiles along with diapsides .
| † Anapsids |
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| Scientific classification |
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| No rank : | Bilateral symmetric |
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| International Scientific Name |
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Anapsida Williston , 1917 |
| Detachments |
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- † Captorhinida
- † Mesosauria
- † Procolophonomorpha
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Traditionally, anapsids were considered as monophyletic taxa of reptiles, however, hypotheses were put forward that some groups of reptiles with anapsid skulls can only be remotely related to each other.
Previously, the living representatives of anapsid were considered turtles . For the first time, turtles were noted in the Upper Triassic , but at that time they already had almost all the anatomical features of modern turtles, with the exception of carapace , that is, their formation should have begun much earlier - in particular, they already had joints inside the rib cage. However, all modern genetic studies have confirmed the previously contested hypothesis that turtles are a group of diapsid reptiles with reduced temporal windows [3] [4] [5] .
Most of the reptiles with anapsid skulls, including the , and parayasaurs , became extinct in the late Permian period during the mass extinction. Prokolofomorfy survived to the Triassic period.