Anteosaur
Encyclopedia
Anteosaurs are a group of large, primitive carnivorous
Dinocephalia
ns (early "mammal-like reptiles"), with huge canines and incisors and short limbs, that are known from the Middle Permian
of South Africa, Russia, and China. The largest grew to very large size, with skulls 50 to 80 cm long, and were the largest predators of their time. They died out at the end of the Middle Permian, possibly as a result of the extinction of the herbivorous Tapinocephalia
on which they fed.
, so that the front of mouth curves strongly upwards. The limbs are short and the skull long, narrow, and heavy. The temporal opening is much larger than in the early Biarmosuchia
, indicating larger jaw muscles and a stronger bite. There is a tendencty especially in more advanced forms such as Anteosaurus
towards thickening of the bones of the top of the skull, indicating head-butting behaviour. The tail is very long in at least some genera.
in 1962 to include the families
Brithopodidae
and Anteosauridae
James Hopson and Herbert Barghusen in 1986 provided the first cladistic
study of the Therapsida. They used the term "Anteosauria" and synonymised the families Brithopodidae and Anteosauridae. They suggested the following schema:
Gillian King
in a 1988 review of the Anomodont
ia (including the Dinocephalia - however the view that the Dinocephalia are a subset of the Anomodontia is no longer held) as part of Gutsav Fischer Verlag's ongoing Encyclopedia of Paleoherpetology series of volumes, uses a more traditional Linnaean arrangement, but includes the herbivorous forms under the superfamily Anteosauroidea as well:
Note that the "Titanosuchidae" here is equivalent to the "Tapinocephalia
".
Finally, as part of a much larger Therapsid cladogram
, Bruce Rubidge and Christian Sidor
in 2001 offer the following:
are more basal
. They have features in common with Pelycosaur
s (Carroll 1988) and Biamosuchians (Chudinov 1965), and, with the Tapinocehalia, are part of the first major evolutionary radiation of the Therapsida (Rubidge & Sidor 2001). So far little work has been done on detailed phylogenetic
relationships between the various taxa
.
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
Dinocephalia
Dinocephalia
Dinocephalia are a clade of large early therapsids that flourished during the Middle Permian, but became extinct leaving no descendants.-Description:...
ns (early "mammal-like reptiles"), with huge canines and incisors and short limbs, that are known from the Middle Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
of South Africa, Russia, and China. The largest grew to very large size, with skulls 50 to 80 cm long, and were the largest predators of their time. They died out at the end of the Middle Permian, possibly as a result of the extinction of the herbivorous Tapinocephalia
Tapinocephalia
The tapinocephalians are one of the major groups of dinocephalian therapsids. Unlike anteosaurs and estemmenosuchids, tapinocephalians are mainly from Africa and only one species is found in the north - Ulemosaurus from Russia. The tapinocephalians are divided into three clades, Styracocephalidae,...
on which they fed.
Characteristics
The Anteosauria are distinguished from the Tapinocephalia by a number of features, such as very large canines, cheek teeth with bulbous crowns, and an upturning of the premaxillaPremaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
, so that the front of mouth curves strongly upwards. The limbs are short and the skull long, narrow, and heavy. The temporal opening is much larger than in the early Biarmosuchia
Biarmosuchia
Biarmosuchia, also known as Eotitanosuchia and Phthinosuchia, is an assemblage of primitive Permian therapsids that represent either a paraphyletic stem group or a very early off-shoot of the main therapsid tree....
, indicating larger jaw muscles and a stronger bite. There is a tendencty especially in more advanced forms such as Anteosaurus
Anteosaurus
Anteosaurus is the name given to an extinct genus of large carnivorous synapsid. It lived during the Capitanian epoch of the Middle Permian in what is now South Africa...
towards thickening of the bones of the top of the skull, indicating head-butting behaviour. The tail is very long in at least some genera.
History of classification
The group was originally defined as a superfamily by L. D. BoonstraLieuwe Dirk Boonstra
Lieuwe Dirk Boonstra was a South African paleontologist whose work focused on the mammal-like reptiles of the Middle and Late Permian, whose fossil remains are common in the South African Karroo...
in 1962 to include the families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Brithopodidae
Brithopodidae
Brithopodidae are a paraphyletic family of primitive mostly carnivorous Dinocephalians known from the Middle Permian of Russia. Nowadays the name is used less often, being replaced by Anteosauria Brithopodidae are a paraphyletic family of primitive mostly carnivorous Dinocephalians known from the...
and Anteosauridae
Anteosauridae
The Anteosauridae or Anteosaurinae are a family or subfamily of very large carnivorous Dinocephalia that are known from the Middle Permian of Russia and South Africa...
James Hopson and Herbert Barghusen in 1986 provided the first cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
study of the Therapsida. They used the term "Anteosauria" and synonymised the families Brithopodidae and Anteosauridae. They suggested the following schema:
Gillian King
Gillian King
Gillian King has worked in teaching and research in paleontology, as Assistant Curator at the Zoological Collections at Oxford University Museum, and a Fellow and Tutor as St Hilda's College, Oxford. She spent 15 years at Oxford and five years at the South African Museum in Cape Town, where she...
in a 1988 review of the Anomodont
Anomodont
The Anomodontia were a major group of therapsids, an extinct group of animals commonly known as "mammal-like reptiles." They were mostly toothless herbivores. During the Middle Permian they were very diverse, including groups like the Venyukovioidea, the Dromasauria, the Dicynodontia, and early...
ia (including the Dinocephalia - however the view that the Dinocephalia are a subset of the Anomodontia is no longer held) as part of Gutsav Fischer Verlag's ongoing Encyclopedia of Paleoherpetology series of volumes, uses a more traditional Linnaean arrangement, but includes the herbivorous forms under the superfamily Anteosauroidea as well:
- Superfamily Anteosauroidea BOONSTRA 1962
- Family Brithopidae BOONSTRA 1972
- Subfamily Brithopodinae EFREMOV 1954
- Subfamily Anteosaurinae 1954
- Family Titanosuchidae BOONSTRA 1972
- Family Brithopidae BOONSTRA 1972
- Subfamily Titanosuchinae BROOM 1903
- Subfamily Tapinocephalinae LYDEKKER 1890
Note that the "Titanosuchidae" here is equivalent to the "Tapinocephalia
Tapinocephalia
The tapinocephalians are one of the major groups of dinocephalian therapsids. Unlike anteosaurs and estemmenosuchids, tapinocephalians are mainly from Africa and only one species is found in the north - Ulemosaurus from Russia. The tapinocephalians are divided into three clades, Styracocephalidae,...
".
Finally, as part of a much larger Therapsid cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
, Bruce Rubidge and Christian Sidor
Christian Sidor
Christian A. Sidor is an American biologist and paleontologist, Associate Professor of the Department of Biology, University of Washington, Seattle, WA, curator of vertebrate paleontology in the Burke Museum of Natural History and Culture, member of the editorial board of the Journal of Vertebrate...
in 2001 offer the following:
Evolutionary relationships
The early Russian (Boonstra 1972) and Chinese (Rubidge & Sidor 2001) Anteosaurs are generally considered the most primitive of the Dinocephalia, and hence of the Eutheropoda (in which case they may constitute a paraphyletic assemblage), although it has also been suggested (Kemp, 1982, King 1988) that the EstemmenosuchidsEstemmenosuchidae
Estemmenosuchidae are a family of large, very early herbivorous mammal-like reptiles that flourished during the Middle Permian period. They are distinguished by horn-like structures, probably for display or agonistic behavior. Apart from the best known genus, Estemmenosuchus, the group is poorly...
are more basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
. They have features in common with Pelycosaur
Pelycosaur
The pelycosaurs are an informal grouping composed of basal or primitive Late Paleozoic synapsid amniotes. Some species were quite large and could grow up to 3 meters or more, although most species were much smaller...
s (Carroll 1988) and Biamosuchians (Chudinov 1965), and, with the Tapinocehalia, are part of the first major evolutionary radiation of the Therapsida (Rubidge & Sidor 2001). So far little work has been done on detailed phylogenetic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
relationships between the various taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
.
Links
- Palaeos - detailed description
- Mikko's Phylogeny Archive - list of genera in the form of a cladogramCladogramA cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...