''Schowalteria'' is a genus of extinct mammal from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. It is the earliest known representative of order

Taeniodonta Taeniodonta ("banded teeth") is an extinct order of eutherian mammals, that lived in North America and Europe from the late Cretaceous (Maastrichtian) to the middle Eocene. Taeniodonts evolved quickly into highly specialized digging animals ...

, a specialised lineage of

eutheria Eutheria (from Greek , 'good, right' and , 'beast'; ), also called Pan-Placentalia, is the clade consisting of Placentalia, placental mammals and all therian mammals that are more closely related to placentals than to marsupials. Eutherians ...

n mammals otherwise found 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), ...

and

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

deposits. It is notable for its large size, being among the largest of

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

mammals, as well as its speciation towards herbivory, which in some respects exceeds that of its later relatives.

Description

Currently, ''Schowalteria'' is considered to be a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus, with only one species, ''S. clemensi''. It is known from only one skull. ''Schowalteria'' shares some speciations with later taeniodonts, namely similar canine and

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

morphology, similar facial proportions and

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 ...

construction, though unlike them its occlusal surface is worn nearly completely flat, and the wear facet completely encompasses the paracone and metacone, leaving only an outline of the buccal side of the bases of these cusps remaining, differing radically from the more "normal" teeth wearing patterns of other taenidonts. Based on the skull's proportions, it was initially comparared in size to '' Didelphodon vorax'', making it one of the largest mammals of the Mesozoic at the time of its discovery, and posterior measurements have cited larger sizes; Anne Weil posits a range similar (though not confirmed) to '' Repenomamus giganticus'', while posterior analysis showcase it to be as large as latter taeniodonts.

Range

''Schowalteria'' occurs in the Trochu deposits of

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

, dating to the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

stage of the

period. This site is part of the larger Edmonton Group, that probably represented a warm,

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

environment. Mammal remains are very common in this site, such as various

metatheria Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as wel ...

ns and multituberculates.

Classification

''Schowalteria'' is a taeniodont eutherian. It was initially recovered as a fairly derived member related to stylinodonts, but more recent examinations show it to be a more basal species within the group, less related to them than '' Onychodectes''.

Phylogeny

Biology

In spite of being a basal taeniodont, ''Schowalteria'' is fairly derived, perhaps more so than later taenidonts. It shares with them similar speciations towards herbivory and possibly fossoriality, but unlike them it also possesses evidence of transverse (

ungulate Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...

-like)

mastication Chewing or mastication is the process by which food is comminution, crushed and ground by the teeth. It is the first step in the process of digestion, allowing a greater surface area for digestive enzymes to break down the foods. During the mast ...

, making it even more specialised towards processing vegetation. As one of the largest mammals of its time period and a rather specialised herbivore, ''Schowalteria'' was a rather spectacular species among the

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

-rich faunas of the end of the Cretaceous.

References

{{Taxonbar, from=Q22944276 Taeniodonta Late Cretaceous mammals of North America Prehistoric eutherians Extinct animals of North America Fossil taxa described in 2003 Prehistoric mammal genera