Taeniolabidoidea is a group of extinct

mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...

known whose fossils can be found in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. They were the largest members of the extinct order

Multituberculata Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct Order (biology), order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the M ...

, as well as the largest non-therian mammals. '' Lambdopsalis'' even provides direct

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

evidence of mammalian

fur A fur is a soft, thick growth of hair that covers the skin of almost all mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an ...

in a fairly good state of preservation for a 60-million-year-old animal. Some of these animals were large for their time; ''

Taeniolabis taoensis ''Taeniolabis'' ("banded incisor") is a genus of extinct multituberculate mammal from the Paleocene of North America. Description ''Taeniolabis'' is a member of the Taeniolabidoidea, a superfamily of multituberculates that are known for the ...

'' is the largest known multituberculate and though smaller, ''

Yubaatar ''Yubaatar'' is a genus of Multituberculata, multituberculate, an extinct order of rodent-like mammals, which lived in what is now China during the Late Cretaceous. The first specimen was discovered in the Qiupa Formation of Luanchuan County, in ...

'' is the largest known Mesozoic Asian multituberculate. ''T. taoensis'' averaged a body mass of . The group was initially established as a

suborder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

, before being assigned the rank of a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

by McKenna and Bell in 1997. Two families are recognised: the primarily North American Taeniolabididae, composed of ''

Taeniolabis ''Taeniolabis'' ("banded incisor") is a genus of extinct Multituberculata, multituberculate mammal from the Paleocene of North America. Description ''Taeniolabis'' is a member of the Taeniolabidoidea, a superfamily of multituberculates that ...

'' and '' Kimbetopsalis'', and the exclusively Asian Lambdopsalidae, composed of '' Lambdopsalis'', '' Sphenopsalis'' and '' Prionessus'', with '' Valenopsalis'' being a basal form outside of either clade. Some of the fossils are well-preserved. Though the possible taeniolabidoid ''

Bubodens ''Bubodens magnus'' is a poorly understood, extinct multituberculate mammal from the Upper Cretaceous of South Dakota. It is known only from a single tooth, and has uncertain placement within the suborder Cimolodonta though has been tentatively a ...

'' is known from the

Lancian The Lancian was a North American faunal stage of the Late Cretaceous. It was the final stage of the Cretaceous period in North America, lasting from approximately 70.6 to 66 million years ago. Geology Terrestrial sedimentary strata from the Judit ...

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

deposits of

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...

, and ''

'' is known from Late Cretaceous deposits in the

Henan Province Henan; alternatively Honan is a province in Central China. Henan is home to many heritage sites, including Yinxu, the ruins of the final capital of the Shang dynasty () and the Shaolin Temple. Four of the historical capitals of China, Luo ...

, the clade is otherwise only clearly represented in

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

. Members of this group have

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

s of or . Russell notes that the taeniolabidoids had ever-growing, self-sharpening incisors, much like modern

rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

, and the premolars that are usually characteristic of multituberculates are sometimes lost in this family. Derived characteristics of the

taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

(apomorphies) include: "snout short and wide with anterior part of

zygomatic arch In anatomy, the zygomatic arch (colloquially known as the cheek bone), is a part of the skull formed by the zygomatic process of temporal bone, zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the ...

es directed transversely, resulting in a square-like shape of the skull (shared with

Kogaionidae Kogaionidae is a family of fossil mammals within the Extinction, extinct order Multituberculata. Representatives are known from the Upper Cretaceous and the Paleocene of Europe. Having started as island endemics on Hațeg Island during the Upper ...

); frontals small, pointed posteriorly, almost or completely excluded from the orbital rim".Kielan-Jaworowska and Hurum 2001, p417

Notes

References

* * * * * * * * {{Taxonbar, from=Q2474030 Multituberculata Paleocene extinctions Late Cretaceous first appearances