Diadectes
genus of reptiles (fossil)
Diadectes (meaning crosswise-biter) is an extinct genus of large reptiliomorphs that lived during the early Permian period (Artinskian-Kungurian stages of the Cisuralian epoch, between 290 and 272 million years ago). Diadectes was one of the first herbivorous tetrapods, and also one of the first fully terrestrial vertebrates to attain large size.
Description
Diadectes was a heavily built animal, up to 3 m (10 ft) long, with a thick-boned skull, heavy vertebrae and ribs, massive limb girdles, and short, robust limbs. The nature of the limbs and vertebrae clearly indicates a terrestrial animal. The rib cage was assumed to be barrel-shaped, but new fossils show the ribs were actually sticking out to the sides.
High-resolution X-ray microcomputed tomography has revealed an endosseous labyrinth in the opisthotic, prootic, and supraoccipital of D. absitus, along with a well-preserved vestibule, three semicircular canals, and a developed cochlear recess. The supraoccipital, which is positioned medially to the anterior semicircular canal, preserves a shallow and subarcuate fossa on its ventral surface. An otic tube leads from the fenestra vestibuli to the vestibule.
Paleobiology
It possesses some characteristics of reptilians and amphibians, combining a reptile-like skeleton with a more primitive, seymouriamorph-like skull. Diadectes has been classified as belonging to the sister group of the amniotes.
The public source identifies “Diadectes” as genus of reptiles (fossil). This brief keeps that definition visible, then builds a research path around Diadectes, genus and reptiles.
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Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Aug 24, 2026. The linked authority identifier is Q132762. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Diadectes” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.