Estemmenosuchus (meaning "crowned crocodile" in Greek) is a genus of large, early omnivorous therapsid. It lived during the middle part of the Middle Permian around 267 million years ago. The two species, E. uralensis and E. mirabilis, are characterized by distinctive horn-like structures, which were probably used for intra-specific display. Both species of Estemmenosuchus are from the Perm (or Cis-Urals) region of Russia. Two other estemmenosuchids, Anoplosuchus and Zopherosuchus, are now considered females of the species E. uralensis. There were many complete and incomplete skeletons found together. Fossilized impressions of its skin have revealed that Estemmenosuchus mostly lacked reptilian scales, having smooth, hairless mammal-like skin similar to that of a modern Hippopotamus.

In the Land Before Time

A blue Estemmenosuchus, during the song, 'Imaginary Friends'

A dark blue Estemmenosuchus appears in The Land Before Time IX: Journey to Big Water, during the song 'Imaginary Friend'. However, he doesn't much resemble the actual animal, having an exaggerated ceratopsian frill instead of horns.