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).[2]

Temporal range: Late Triassic - Holocene, 220–0 Ma
Life restoration of a Gobiconodon
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Holotheria
Wible et al., 1995


According to McKenna/Bell (1997):[1]

According to Wang, Clemens, Hu & Li, 1998[3]


  1. ^ a b c Mckenna. "Holotheria". Mikko's Phylogenetical Archive. Retrieved 19 July 2013.
  2. ^ Wible, J. R., Rougier, G. W., Novacek, M. J. & McKenna, M. C. (2001). "Earliest eutherian ear region: A petrosal referred to Prokennalestes from the Early Cretaceous of Mongolia." American Museum Novitates, 3322.
  3. ^ Wang, Clemens, Hu & Li. "Holotheria". Mikko's Phylogenetical Archive. Retrieved 19 July 2013.CS1 maint: Multiple names: authors list (link)

The Amphidontidae are a family of extinct mammals from the Early Cretaceous, belonging to the triconodonts. It contains most of the species previously belonged to Amphilestidae.


Amphitheriida is an order of Mesozoic mammals restricted to the Middle Jurassic of Britain. They were closely related to the Dryolestids but possessed five molars instead of the usual four in Dryolestida, (with the exception of the family Dryolestidae whose members possessed between 8 and 9 molars). The Amphitheriida contains one family, the Amphitheriidae.


Chronoperates (meaning "time wanderer" in Greek) is an extinct genus of mammal whose remains have been found in a late Paleocene deposit in Alberta, Canada. It is represented by the type species Chronoperates paradoxus and known only from a partial left lower jaw. It was first identified in 1992 as a non-mammalian cynodont, implying a ghost lineage of over 100 million years since the previously youngest known record of non-mammalian cynodonts, which at that time was in the Jurassic period (some non-mammalian cynodonts are now known to have persisted until the Early Cretaceous). Subsequent authors have challenged the cynodont interpretation, particularly as the teeth do not resemble any known cynodonts. Chronoperates is now generally considered to be more likely to be a late-surviving symmetrodont mammal. This would still infer a ghost lineage for symmetrodonts, but a more plausible one, as symmetrodonts persisted into the Late Cretaceous.


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


Henkelotherium is an extinct genus of mammal from the Late Jurassic (Kimmeridgian) Camadas de Guimarota, in Portugal. It differs from most other paurodontids in having more postcanine teeth.


Kuehneotheria is a group of basal mammals that were once classified in the now paraphyletic Symmetrodonta. It was named by Mckenna in 1995.


Kuehneotheriidae is a family traditionally within 'Symmetrodonta', though now generally considered more basal than true symmetrodonts. All members of Kuehneotheriidae which have been found so far are represented only by teeth, but these teeth have features which have led paleontologists to classify Kuehneotheriidae as very close relatives of the first true mammals. But fossil clades based solely on teeth often lead to difficulties (Ausktribosphenidae are a good example), and it is not possible to draw significant conclusions about mammalian evolution from the Kuehneotheriidae unless some more complete skeletons are found.


Kuehneotherium is an early mammaliaform genus that lived during the late Triassic period and is characterized by reversed-triangle pattern of molar cusps. Although a large number of fossils have been found, the fossils are limited to teeth, dental fragments, and mandible fragments. The genus includes Kuehneotherium praecursoris and all related species. It was first named and described by Doris M. Kermack, K. A. Kermack, and Frances Mussett in November 1967. The family Kuehneotheriidae and the genus Kuehneotherium were created to house the single species Kuehneotherium praecursoris. Modeling based upon a comparison of the Kuehneotherium jaw with other mammals indicates they were about the size of a modern-day shrew between 4 and 5.5 g at adulthood.

Kuehneotherium is thought to be an insectivore that could consume only soft-bodied insects such as moths. Their teeth were shaped for vertical shearing and could not crush harder prey. They lived alongside another early mammal, Morganucodon, which had teeth that could crush harder insects such as beetles. This distinction in diet shows that early mammals adapted to have a separate feeding niche so they would not compete for food.


Meridiolestida is a clade of non-therian mammals from South America and Africa, and potentially also Australia. It is generally classified within Dryolestida, barring one study recovering them as the sister taxa to spalacotheriid symmetrodonts. However, more recent studies have stuck to the dryolestoid interpretation. They differ from northern dryolestoids in the absence of a parastylar hook on the molariform teeth and the lack of a Meckelian groove.

Mole (animal)

Moles are small mammals adapted to a subterranean lifestyle (i.e., fossorial). They have cylindrical bodies; velvety fur; very small, inconspicuous ears and eyes; reduced hindlimbs; and short, powerful forelimbs with large paws adapted for digging.

The term mole is especially and most properly used for "true moles" of the Talpidae family in the order Eulipotyphla, which are found in most parts of North America, Asia, and Europe, although it may also refer to unrelated mammals of Australia and southern Africa that have convergently evolved the "mole" body plan. The term is not applied to all talpids; e.g., desmans and shrew-moles differ from the common definition of "mole".

Moles are known pests to human activities such as agriculture, lawncare, and gardening. However, they do not eat plant roots; they only cause damage indirectly as they eat earthworms and other small invertebrates in the soil.


Preptotheria is a superorder of placental mammals proposed by McKenna & Bell in their classification of mammals.


Shuotherium is a fossil mammal known from Middle-Late Jurassic of the Forest Marble Formation of England, and the Shaximiao Formation of Sichuan, China.The original holotype is composed of a partial dentary and seven teeth (two which are incomplete). The holotypes for other species of this genus are solely represented by isolated molars. Shuotherium, along with Pseudotribos has been placed in the family Shuotheriidae as a sister taxon of the Australosphenida (see, Yinotheria), making it a relative of modern monotremes. However, some studies place it and other shuothereres as closer to therian mammals.


Spalacotheriidae is a family of extinct mammals belonging to the group Symmetrodonta. They were a rather successful lineage, lasting from the Early Cretaceous to Campanian in North America, Europe, Asia and North Africa. The lack of a Meckelian groove indicate that they had a modern ear anatomy, and their deciduous canines and premolars as well as long lower jaw indicate a carnivorous/insectivorous diet.


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 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 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 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.


Woutersia was a Triassic kuehneotherid and the only representative of its family. It has been suggested that it may form the sister taxon to Docodonta. Its remains have been found in France.


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).


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