''Protungulatum'' ('first

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 ...

') is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 ...

mammal A mammal () is a vertebrate animal of the Class (biology), 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 ...

s within extinct family Protungulatidae, and is possibly one of the earliest known placental mammals in the fossil record, that lived 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 ...

from the

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 ...

to early

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), ...

.Maeva Orliac (2016.
"The inner ear of ''Protungulatum'' (Pan-Euungulata, Mammalia)"
Journal of Mammalian Evolution 23(4) Fossils of this genus were first found in the Bug Creek Anthills in northeastern

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

. The Bug Creek Anthills were initially believed to be Late Cretaceous (latest

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 ...

) because of the presence of the remains of non-avian

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 ...

s and common Cretaceous mammals, but these were later shown to have been reworked from Late Cretaceous

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 ...

, and consequently the Bug Creek Anthills are currently believed to be Early Paleocene ( Puercan) in age. Remains from the Ravenscrag Formation of

Saskatchewan Saskatchewan is a Provinces and territories of Canada, province in Western Canada. It is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by 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 ...

have been assigned to ''Protungulatum donnae''. These remains may also be Cretaceous in age, but the age of the Ravenscrag Formation is not entirely certain. In

2011 The year marked the start of a Arab Spring, series of protests and revolutions throughout the Arab world advocating for democracy, reform, and economic recovery, later leading to the depositions of world leaders in Tunisia, Egypt, and Yemen ...

, a new species ''Protungulatum coombsi'' was named based on fossil material discovered from the strata within the Hell Creek Formation specifically dated to at least 300,000 years before the K-Pg extinction, suggested that ''Protungulatum'' was present in both the latest Cretaceous and the early Paleocene. ''P. coombsi'' was estimated to be 20% larger than the next largest Paleocene species. Studies differ on the placement of ''Protungulatum.'' This genus was initially assigned to the family Arctocyonidae, in order Condylarthra,Malcolm C. McKenna, Susan K. Bell: ''Classification of Mammals: Above the Species Level'' in Columbia University Press, New York (1997), 631 Seiten. (a group of archaic "ungulates", that is now known to be

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

). Some found that it is not a true placental mammal and it is

n found to be close to

Placentalia Placental mammals ( infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distingui ...

. However, a number of studies consider it to be a placental mammal and stem relative to true ungulates in clade Pan-Euungulata,Conference abstract (p. 99)
. Explanation and conclusions: . based on anatomy of

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

Phylogeny

The phylogenetic relationships of genus ''Protungulatum'' are shown in the following cladogram.

Notes

References

{{Taxonbar, from1=Q2197682, from2=Q3924358 Prehistoric eutherians † Cretaceous mammals Paleocene mammals Hell Creek fauna Prehistoric mammals of North America Fossil taxa described in 1965 Prehistoric mammal genera