Palaeos		Therapsida
Vertebrates		420: Dinocephalia: Estemmenosuchidae

Therapsida: Dinocephalia: Estemmenosuchidae

SYNAPSIDA
|
THERAPSIDA
|--Biarmosuchia
`--Eutherapsida
`--+--Dinocephalia
   |  |--Stenocybus
   |  |--Estemmenosuchidae
   |  |  |--Anoplosuchus
   |  |  `--+--Estemmenosuchus
   |  |     |--Molybdopygus 
   |  |     `--Zopherosuchus
   |  `--+--Anteosauria
   |     `--Tapinocephalia
   `--+--Anomodontia
      |  |--Venyukovioidea
      |  `--Dicynodontia   
      `--Theriodontia
         |--Gorgonopsia
         `--+--Therocephalia
            `--CYNODONTIA

Taxa on This Page

1. Anoplosuchus X
2. Estemmenosuchidae X
3. Estemmenosuchus X
4. Molybdopygus X
5. Zopherosuchus X

Dinocephalia: Estemmenosuchidae

Estemmenosuchus uralensis - life reconstruction artwork by Mojcaj - Wikipedia

With the decline of the Kungurian and Ufimian caseids, the herbivorous Estemmenosuchidae took over the role of top herbivore. These were massive, clumsy-looking animals, with a sprawling posture, reaching the size of an adult bull, although some types were smaller.

The skull is high and massive. The creature is equipped with several bizarre set of large horns projecting both upwards and outwards, probably used for intra-specific display. There are five large teeth on the maxillae (upper jaw bone), rather short canines, and at least twenty small and uniform post-canines. Each tooth has a swollen crown and a sharp, laterally compressed at the apex. There are also numerous small teeth on the palate (vomers, palatines and pterygoids). The reduced side teeth, with a bulky body for digesting volumes of plant food, indicate a herbivorous lifestyle, despite the large canines. Vegetable matter was grasped with the strong front teeth and swallowed without chewing, as the weak and thin side teeth only served to keep food in the mouth. These animals would nevertheless have taken carrion when they could find it, as the great force exerted by the chisel-like front teeth could cut up meat quite easily.

As with the tapinocephalids of the early Capitanian epoch, a number of types are known, and it seems that, for a short time, the estemmenosuchids constituted a successful evolutionary radiation. Connections are sometimes suggested with Styracocephalus, but in the estemmenosuchids the 'horns' are situated on the frontals and directed dorsally. In Styracocephalus the 'horns' are formed by the tabular and directed posteriorly. Otherwise their features very similar to those of Styracocephalus. It is not possible to say therefore whether the relationship is one of ancestor- descendent or simply evolutionary convergence due to similar lifestyle, although difference in the bones forming the horns would suggest the latter.

The remains of Estemmenosuchus have been found in a channel flood deposit, indicating that they probably frequented lowland and marshy areas.  MAK000725.

Suborder Dinocephalia Family Estemmenosuchidae Species Estemmenosuchus uralensis Chudinov 1960 Estemmenosuchus mirabilis Chudinov 1968 Anoplosuchia tenuirostris Chudinov 1968 Zopherosuchus luceus Chudinov 1983 Horizon: Upper Kazanian or Lower Tartarian Substage, Middle Permian Locality: Echovo locality, Ocher Province, Perm Region, Russia Possible age: Middle or Late Wordian Known remains: elements of skulls and postcrania skull, lower jaw and vertebrae incomplete skeleton and skull poorly preserved skeleton and incomplete skull Length (skull): 65 cm 40 cm no information no information Length (total): upto 4 meters over 3 meters intermediate in size 1.5 meters

Estemmenosuchus mirabilis - illustration copyright © Satoshi Kawasaki Comments: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. 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. 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. 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. 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 prominant 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. References:Olson, 1962, King 1988, Vickers-Rich and Rich, 1993 Links: Estemmenosuchus uralensis skeleton; Estemmenosuchus uralensis skull; Estemmenosuchus mirabilis life illustration

Estemmenosuchidae: Parabradysaurus?

Range: Middle Permian (uppermost Kazanian) to Late Permian (lower Tatarian) of Russia

Phylogeny: Dinocephalia: (Anteosauria + Tapinocephalidae) + *: Anoplosuchus + (Estemmenosuchus + Molybdopygus + Zopherosuchus)

Characters: medium to large size; skull with heavy pachyostosis [BS00]; often with numerous knob-like or horn-like protuberances [BS00]; teeth on vomers [BS00]; tail short; herbivorous. 

Links: dinosaurs-estemmenosuchus uralensis; Gondwona Studios; Estemmenosuchus Printout - Enchanted Learning Software.  

References: Battail & Surkov (2000) [BS00]. ATW020522.

Anoplosuchus: A. tenuirostris Tchudinov 1968b

Range: Middle Permian (uppermost Kazanian) to Late Permian (lower Tatarian) of Russia (Ocher District)

Phylogeny: Estemmenosuchidae: (Estemmenosuchus + Molybdopygus + Zopherosuchus) + *.

Characters: medium-sized [BS00]; skull narrow; preorbital region long, low & broad; outer edge of jaw in region of canine bears weak boss; preorbital skull without excrescences or thickening [BS00] except in posterior nasal region (?); postorbital (skull?) short, weak, broad & high; incisors more or less equal in size to canines [BS00]; numerous small post-canine teeth [BS00].

Links: paleng2_0p189abs (abstract of Ivakhnenko article stating that Anoplosuchus is synonymous with Estemmenosuchus & Zopherosuchus); RepTherapS.pdf;

References: Battail & Surkov (2000) [BS00]

Note: known from an incomplete skeleton and skull plus referred skull & jaw fragments.  ATW020522, MAK000725.

Estemmenosuchus: E. uralensis Tchudinov, 1960; E. mirabilis Tchudinov, 1968.

Range: Middle Permian (uppermost Kazanian) to Late Permian (lower Tatarian) of Russia (Ocher District).

Phylogeny: Estemmenosuchidae:: Molybdopygus + Zopherosuchus + *.

Characters: bull-sized; massive skull [BS00]; rather spectacular "horns;" anterior nasal form unpaired boss on dorsal snout [BS00]; jugal & squamosal form massive lateral outgrowth (see image at right) [BS00]; long, curved incisors [BS00]; canines short & thick [BS00]; at least 20 weak marginal teeth [BS00]; note the typically herbivorous teeth in image at left. 

Links: dinosaurs-estemmenosuchus uralensis; Estemmenosuchus Printout - Enchanted Learning Software; therapsid3b. 

Note: 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 mirabilis.  [BS00].  

References: Battail & Surkov (2000) [BS00].  ATW020522.

Molybdopygus: (= Deuterosaurus) M. arcanus Tchudinov 1964

Range: Late Permian of Russia, Bolshoi Kitiak, Malmych, Kirov.  Lower Tatarian Substage.  

Phylogeny: Estemmenosuchidae: Estemmenosuchus + Zopherosuchus + *.

Characters: known only from pelvic bones.  Smaller than Estemmenosuchus, but perhaps more massively built [BS00]; flat facets at posterior end of acetabulum; high pubo-ischiadic symphysis. 

References: Battail & Surkov (2000) [BS00].  ATW020523

Zopherosuchus: Z. luceus Tchudinov 1983.

Range: Middle Permian (uppermost Kazanian) to Late Permian (lower Tatarian) of Russia (Ocher District).

Phylogeny: Estemmenosuchidae:: Estemmenosuchus + Molybdopygus + *.

Characters: small-bodied [BS00]; no cranial horns [BS00]; frontals & parietals particularly thick; temporal fenestrae short, but very tall [BS00]; relatively small number of postcanine teeth [BS00].

References: Battail & Surkov (2000) [BS00].  ATW020524.