The stapes of Thrinaxodon Seeley, 1894 and Galesaurus Owen, 1859: a case of study for intraspecific variability in basal cynodonts

We surveyed the stapedial anatomy of Thrinaxodon liorhinus Seeley, 1894 and Galesaurus planiceps Owen, 1859, two iconic Early Triassic basal cynodonts. The complete characterization this bone analysis its morphological variability along ontogeny within each taxon were possible through study eleven elements nine 1859. Our results highlight notable qualitative quantitative differences among specimens same species. Stapes growth model in shows a positive allometry on lateromedial length anteroposterior width, whereas there is negative width but isometric. This offers counterintuitive result inordinate high intraspecific variation stapes non-mammaliaform