America and South America, could represent caseids footprints. In 2019, Marchetti and colleagues, however, reinterpreted Chelichnus as a nomen dubium and a taphotaxon, this type of track showing false anatomical features generated by locomotion on sandy inclined paleosurface. In 2014, Eva Sacchi and colleagues described the ichnotaxon Dimetropus osageorum from about a hundred isolated footprints and several trackways from the early Permian Wellington Formation in Oklahoma. The morphological study of these footprints and their comparison with tetrapod skeletons revealed that they probably belong to a large caseid comparable in size to Cotylorhynchus romeri (the latter from more recent strata). According to Sacchi and colleagues, some footprints from the Lodève Basin (unspecified geological formation) are similar to those from the Wellington Formation and these authors designate them as Dimetropus cf. osageorum. The study by Sacchi et al. also demonstrates that the ichnogenus Dimetropus exhibits great morphological variation and that its producers can be assigned to different zoological groups among non-therapsid synapsids and not just Sphenacodontidae as once thought. In 2021, Rafel Matamales-Andreu and colleagues assigned footprints found in the Lower Permian (Artinskian-Kungurian) Port des Canonge Formation in Mallorca to a caseid. These footprints resemble those of D. osageorum but they also have differences. These footprints are left in open nomenclature as cf. Dimetropus sp.. They are, however, smaller than those of D. osageorum and would have been produced by a caseid of modest size with proportions comparable to Ennatosaurus. Paleobiology Diets During their evolutionary history, caseids shifted from faunivorous to herbivorous diet, a pattern that also occurred independently in other Carboniferous and Permian tetrapod groups such as Captorhinidae and Edaphosauridae. Earliest and most basal caseids, such as the late Carboniferous Eocasea and the early Permian Callibrachion had an unexpanded rib cage and dentition composed of very small conical teeth suggesting an insectivorous diet. Another basal caseid, Martensius, has a slightly enlarged barrel-shaped trunk and dentition in which teeth indicative of an insectivorous diet in juveniles have been ontogenetically replaced in adults by teeth suggesting an omnivorous diet. In Martensius, the adult was still able to feed on insects, but it also possesses a draft of the herbivorous diet specializations present in later caseids, such as a relatively short, slightly forward-inclined snout, and a dentition that is almost homodont in the upper jaws and completely homodont in lower jaws. The sequence of dental trait acquisition in Martensius suggests that intestinal vegetation processing