Therapsida: Dinocephalia: Estemmenosuchidae

The Estemmenosuchids represent the first major evolutionary radiation of therapsid herbivores. Still rare during the Roadian age, they come into their own during the Wordian, when a number of types of animals occur together; clearly representing a mature evolutionary assemblage, like the Capitanian tapinocephalids whose fossil remains are known from the South African Karoo (Beaufort Group). They range in size from medium-sized animals like Zopherosuchus, to the large Estemmenosuchus which was the biggest animal of its day. The fossil remains of the Estemmenosuchids are so far not known beyond the Permian deposits of the Urals, which at the time was an equatorial lowland environment. So these animals seem to have been tropical, possibly swamp loving, herbivores. The name Estemmenosuchus means "Crested Crocodile", and refers to the strange horns or bony antlers. These animals are distinguished by their bizarre crests and flanges of bone, which were probably for intra-specific behavior. There is great individual variation.

known from an incomplete skeleton and skull plus referred skull & jaw fragments.

Anoplosuchia tenuirostris was a fairly uncommon, medium sized estemmenosuchid with a comparatively narrow skull. There are no horns or thickening, except in the front nasal region.

Known remains consist of incomplete skeleton and skull

E. uralensis is larger, with a longer skull in proportion to width. The postorbitals & postfrontals form a pair of partially fused horn-like protuberances on the skull table just posterior to the orbits. E. mirabilis is smaller, with a shorter skull. The horn pair is shorter, well-separated and the horns extend more laterally. Note that the image at right is a E. mirabilis. [BS00].

Estemmenosuchus uralensis was a common, very large (upto 4 meters long - Chudinov 1960 quoted in Olson, 1962 p.79) estemmenosuchid, about the size of a rhinoceros (Vickers-Rich and Rich, 1993), with less prominent horns then E. mirabilis. Originally all specimens were included in this species, but it was since realised that wthere were a number of different species (however, not all palaeontologists agree that these were different species. According to Ivakhnenko 1998 Anoplosuchus and Zopherosuchus are synonyms of Estemmenosuchus uralensis). This peaceful herbivore had much to fear from the giant Eotitanosuchid Ivantosaurus, the only creature in its environment big enough to take on an adult Estemmenosuchus.

Known remains consist of elements of skulls and postcrania

Estemmenosuchus mirabilis was a fairly uncommon, large estemmenosuchid with spectacular moose-like "horns". It had a shorter face than the type species E. uralensis. According to Vickers-Rich and Rich, 1993 irt was about the size of a rhinoceros.

Known remains consist of skull, lower jaw and vertebrae

Zopherosuchus luceus was a fairly uncommon, relatively small estemmenosuchid (although still large relative to other animals in its environment). Some of bones at the front of the skull are particularly thickened.

Known remains consist of poorly preserved skeleton and incomplete skull