Hidden dental diversity in the oldest terrestrial apex predator Dimetrodon

A sampled sphenacodontoid analysis places the included Dimetrodon species within Sphenacodontidae and recovers repeated dental-character changes; this is a character-matrix result, not evidence that Dimetrodon was a direct mammalian ancestor.

This dossier is limited to the Dimetrodon and cf. Dimetrodon teeth and skull material explicitly sampled by Brink and Reisz; the study's sphenacodontid placement is a matrix result and not direct ancestry.

The profile maps only the Early Permian Texas and New Mexico sample, including Archer City, Mount Barry, Briar Creek, Rattlesnake Canyon and the Craddock bonebed; it does not assert a complete geographic distribution.

The authors interpret sphenacodontids, including the sampled Dimetrodon material, as fully terrestrial apex predators and relate dental-character change to feeding style and trophic interactions; direct prey use and locomotor performance were not observed for each specimen.

MCZ 2779, MCZ 2028, ROM 64021 and UMMP 9722 document the sampled Dimetrodon snout and teeth, including enlarged anterior teeth, carinae and variation in lingual cusp morphology; these observations do not diagnose every species or individual of the genus.

Dimetrodon is displayed at 290.1–273 Ma only as the Early Permian species sample used for dental and phylogenetic analysis, not a complete global genus range. The interval is a source-bounded sample window, not a global FAD, LAD, divergence date, continuous occupancy claim or direct-ancestor assertion.