The data I have
for Estemmenosuchus comes from a well-lit by low resolution image complete with halftone dots and moire patterns (Fig. 1). Nevertheless, I think I can find sutures on the image.
Estemmenosuchus uralensis (Middle Permian, Tchudinov 1960, 1968; Holotype PIN 1758/4 Skull length: 60 cm; E. mirabilis PIN 1758/6) could be an omnivore. Considering its bulk and short thick legs, it is more likely an herbivore, like a hippo.
According to Wikipedia, “The fossil material includes an exceptionally well preserved skin impression. The skin appears to be smooth and undifferentiated with no signs of either hairs or scales but with evidence of being well supplied with glands.”
So I made a big mistake
back in 1991 when I illustrated Estemmenosuchus with scales on the cover of this book. The longer you linger the more you learn.
Tchudinov PK 1960. Diagnosen der Therapsida des oberen Perm von Ezhovo: Paleontologischeskii Zhural, 1960, n. 4, p. 81-94.
Tchudinov PK 1968. Structure of the integuments of theriomorphs. Doklady Acad. Nauk SSSR. 179:207-210.