The taeniodonts were an early group of mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s who lived from the Palaeocene to the Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

. This group evolved

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

 quickly into highly specialized digging animal

Animal

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

s. Taeniodont species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 varied greatly in size, from rat

Rat

Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...

-sized to species as large as a bear

Bear

Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...

. Later species developed prominent front teeth

Tooth

Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...

 and huge claw

Claw

A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...

s for digging and rooting. Some genera, like Stylinodon

Stylinodon

Stylinodon is an extinct genus of taeniodont mammal, and is the best known, and last genus of taeniodonts, lived some 45 million years ago during middle Eocene in North America....

, had ever-growing teeth.

Only one family

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...

 belongs to this group, the stylinodontids. They were endemic to North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. The scarcity of taeniodont fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s can be explained by the fact that these animals probably lived in the drier parts of the continent where fossilization was less frequent. Taeniodonts may be related to Cimolesta

Cimolesta

Cimolesta is an extinct order of mammals. A few experts place the pangolins within Cimolesta, though most other experts prefer to place the pangolins within their own order, Pholidota....

.

Taxonomy

From McKenna and Bell (1997):

• Order Cimolesta
  • Suborder Taeniodonta
    • Family Stylinodontidae
      • • Onychodectes
        • Conoryctella
      • Subfamily Conoryctinae
        • Huerfanodon
        • Conoryctes
      • Subfamily Stylinodontinae
        • Schochia
          Schochia
          Schochia sullivani is a primitive species of Taeniodont mammal from the early Paleocene of North America.-References:Lucas, Spencer G. and Thomas E. Williamson. "A New Taeniodont from the Paleocene of the San Juan Basin, New Mexico." Journal of Mammology Vol. 74, No. 1 , p. 175-179....
          
          
        • Wortmania
        • Psittacotherium
          Psittacotherium
          Psittacotherium is an extinct genus of taeniodont from the Paleocene of North America.- Sources :*Mammoths, Sabertooths, and Hominids by Jordi Agusti and Mauricio Anton*The Beginning of the Age of Mammals by Kenneth D. Rose...
          
          
        • Ectoganus
        • Stylinodon
          Stylinodon
          Stylinodon is an extinct genus of taeniodont mammal, and is the best known, and last genus of taeniodonts, lived some 45 million years ago during middle Eocene in North America....