''Estemmenosuchus'' (meaning "crowned crocodile" in
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
) is an
extinct genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of large, early
omnivorous
An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...
therapsid
Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...
. It is believed and interpreted to have lived during the middle part of the
Middle Permian
The Guadalupian is the second and middle series/ epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± ...
around 267 million years ago. The two species, ''E. uralensis'' and ''E. mirabilis'', are characterised by distinctive horn-like structures, which were probably used for
intra-specific display. Both species of ''Estemmenosuchus'' are from the
Perm
Perm or PERM may refer to:
Places
*Perm, Russia, a city in Russia
** Permsky District, the district
**Perm Krai, a federal subject of Russia since 2005
**Perm Oblast, a former federal subject of Russia 1938–2005
**Perm Governorate, an administra ...
(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.
Description
''Estemmenosuchus'' could reach a body length of more than .
Its skull was long and massive, up to in length,
[ and possessed several sets of large horns, somewhat similar to the antlers of a ]moose
The moose (in North America) or elk (in Eurasia) (''Alces alces'') is a member of the New World deer subfamily and is the only species in the genus ''Alces''. It is the largest and heaviest extant species in the deer family. Most adult ma ...
, growing upward and outward from the sides and top of the head. The animal had a sprawling posture as indicated by analysing its shoulder joint
The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint ...
s.
The skull superficially resembles that of '' Styracocephalus'', but the "horns" are formed from different bones; in ''Estemmenosuchus'' the horns are located on the frontals and protrude upward, whereas in Styracocephalus the horns are formed by the tabular and extend aft.
Species
''Estemmenosuchus'' is interpreted to have lived some 267 million years ago. Two species have been identified, from the Ocher Assemblage Zone Belebei Formation at the Ezhovo locality near Ochyor in the Perm
Perm or PERM may refer to:
Places
*Perm, Russia, a city in Russia
** Permsky District, the district
**Perm Krai, a federal subject of Russia since 2005
**Perm Oblast, a former federal subject of Russia 1938–2005
**Perm Governorate, an administra ...
region of the Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
in 1960. They were found with the Biarmosuchians '' Eotitanosuchus olsoni'' and ''Biarmosuchus tener
''Biarmosuchus'' is an extinct genus of biarmosuchian therapsids that lived around 267 mya during the Middle Permian period. ''Biarmosuchus'' was discovered in the Perm region of Russia. The first specimen was found in channel sandstone that w ...
'' in channel flood deposits of the young Ural Mountains
The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...
. They differ in size, shape of the skull, and shape of the horns.
Originally all specimens were included in ''Estemmenosuchus uralensis'', but it was since realised that there 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''.
Paleobiology
Thermoregulation
It has been suggested that the animal had a fairly constant internal temperature. Its large size and compact build gave a small surface-to-volume ratio and suggests it would not gain (or lose) temperature quickly. This phenomenon is called gigantothermy Gigantothermy (sometimes called ectothermic homeothermy or inertial homeothermy) is a phenomenon with significance in biology and paleontology, whereby large, bulky ectothermic animals are more easily able to maintain a constant, relatively high bod ...
and was probably an important factor in temperature regulation in most therapsids.
Skin
P. Chudinov reported skin impressions belonging to ''Estemmenosuchus'' in 1968. The skin was described as being " glandular" like that of a hairless mammal or a frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
.
References
Further reading
* Chudinov, P. K. 1965, "New Facts about the Fauna of the Upper Permian of the USSR", ''Journal of Geology
''The Journal of Geology'' publishes research on geology, geophysics, geochemistry, sedimentology, geomorphology, petrology, plate tectonics, volcanology, structural geology, mineralogy, and planetary sciences. Its content ranges from planetary evo ...
'', 73:117-30
* King, Gillian M., "Anomodontia" Part 17 C, '' Encyclopedia of Paleoherpetology'', Gutsav Fischer Verlag, Stuttgart and New York, 1988
* Olsen, E. C., 1962, Late Permian
Late may refer to:
* LATE, an acronym which could stand for:
** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia
** Local-authority trading enterprise, a New Zealand business law
** Local average treatment effect, ...
terrestrial vertebrates, USA and USSR '' Transactions of the American Philosophical Society'', new series, 52:1–224
* Patricia Vickers-Rich and Thomas H. Rich, The Great Russian Dinosaurs, Guntar Graphics, 1993, p. 30
External links
Palaeos
- detailed description
{{Taxonbar, from=Q133120
Tapinocephalians
Prehistoric therapsid genera
Wordian genera
Guadalupian synapsids of Europe
Permian Russia
Fossils of Russia
Fossil taxa described in 1960