Zatheria

Zatheria is a group (sublegion) of mammals that includes the common ancestor of Arguimuridae, Vincelestidae, Peramuridae and Tribosphenida (living therians plus all of its ancestors).

Zatheria
Temporal range: Middle Jurassic - Holocene, 165–0 Ma
Kangaroo and joey03
Kangaroo with her joey
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Cladotheria
Clade: Zatheria
McKenna, 1975
Subgroups

Phylogeny

Below is a cladogram from Rowe (1988) and McKenna and Bell (1997) showing one hypothesis of mammal relationships:[1][2]

Mammaliaformes 

Morganucodontidae

Mammalia 

PrototheriaMonotremata

Theriiformes

Allotheria→†Multituberculata

Holotheria

Kuehneotheria

Trechnotheria

Amphiodon

Symmetrodonta

Zhangheotherium

 Cladotheria 

Dryolestoidea

 Zatheria 

Peramura

Tribosphenida

Aegialodontia

 Theria 

MetatheriaMarsupialia

EutheriaPlacentalia

Further reading

  • McKenna, Bell: Classification of Mammal: Above the Species Level

References

  1. ^ Rowe, Timothy (1988). "Definition, diagnosis, and origin of Mammalia". Journal of Vertebrate Paleontology. 8 (3): 241–264. doi:10.1080/02724634.1988.10011708. ISSN 0272-4634.
  2. ^ McKenna, Malcolm C.; Bell, Susan K. (1997). Classification of Mammals Above the Species Level. Columbia University Press. pp. 9–10. ISBN 978-0-231-11012-9. Retrieved 16 March 2015.

External links

Cladotheria

Cladotheria is a group (legion) of mammals that includes the ancestor of Dryolestoidea, Peramuridae and Zatheria (living therians plus all of its ancestors).

Holotheria

Holotheria are a diverse group of mammals that are descendants of the last common ancestor of Kuehneotherium and Theria (the group that includes marsupials and placental mammals).

List of prehistoric mammals

This is an incomplete list of prehistoric mammals. It does not include extant mammals or recently extinct mammals. For extinct primate species, see: list of fossil primates.

Mammal classification

Mammalia is a class of animal within the Phylum Chordata. Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is universally accepted; McKenna & Bell (1997) and Wilson & Reader (2005) provide useful recent compendiums. Many earlier ideas from Linnaeus et al. have been completely abandoned by modern taxonomists, among these are the idea that bats are related to birds or that humans represent a group outside of other living things. Competing ideas about the relationships of mammal orders do persist and are currently in development. Most significantly in recent years, cladistic thinking has led to an effort to ensure that all taxonomic designations represent monophyletic groups. The field has also seen a recent surge in interest and modification due to the results of molecular phylogenetics.

George Gaylord Simpson's classic "Principles of Classification and a Classification of Mammals" (Simpson, 1945) taxonomy text laid out a systematics of mammal origins and relationships that was universally taught until the end of the 20th century.

Since Simpson's 1945 classification, the paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself, partly through the new concept of cladistics. Though field work gradually made Simpson's classification outdated, it remained the closest thing to an official classification of mammals. See list of placental mammals and list of monotremes and marsupials for more detailed information on mammal genera and species.

Palaeoxonodon

Palaeoxonodon is an extinct genus of Cladotherian mammal from the Middle Jurassic of England and Scotland.

Peramuridae

The family Peramuridae is a possible ancestor of early therians. The only certain representative (Peramus) lived in the Late Jurassic and Early Cretaceous.

Theria

Theria (; Greek: θηρίον theríon, wild beast) is a subclass of mammals amongst the Theriiformes (the sister taxon to Yinotheria). Theria includes the eutherians (including the placental mammals) and the metatherians (including the marsupials).

Theriiformes

Theriiformes is a subclass of mammals. The term was coined in 1997 by McKenna & Bell in their classification of mammals. In the strict sense, it is defined as all mammals more closely related to therians than to monotremes.

Trechnotheria

Trechnotheria is a group of mammals that includes the therians and some fossil mammals from the Mesozoic Era. In the Jurassic through Cretaceous periods, the group was endemic to what would be Asia and Africa.Trechnotheria has been assigned various ranks, but was originally called a "superlegion" by the original author.

One reference has defined the Trechnotheria as the clade comprising the last common ancestor of Zhangheotherium and living therian mammals, and all its descendants.

Tribosphenida

Tribosphenida is a group (infralegion) of mammals that includes the ancestor of Hypomylos, Aegialodontia and Theria (the last common ancestor of marsupials and placentals plus all of its descendants). Its current definition is more or less synonymous with Boreosphenida.

Wessex Formation

The Wessex Formation is a fossil-rich English geological formation that dates from the Berriasian to Barremian stages (about 145–125 million years ago) of the Early Cretaceous. It forms part of the Wealden Group and underlies the younger Vectis Formation and overlies the Durlston Formation. The dominant lithology of this unit is mudstone with some interbedded sandstones.

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