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Albertatherium
''Albertatherium'' (meaning "beast of Alberta") is an extinct genus of alphadontid metatherians that lived during the Late Cretaceous of North America. The genus contains two species, ''Albertatherium primus'' (the type species), and ''Albertatherium secundus''. Fossils have been found in the Eagle Formation of Montana and the Milk River Formation of Alberta. Taxonomy ''Albertatherium'' is a member of the Alphadontidae, an extinct family of metatherians closely related to marsupials. Recent phylogenetic studies group it with other northern non-marsupial metatherians such as ''Alphadon ''Alphadon'' is an extinct genus of small, primitive mammal that was a member of the metatherians, a group of mammals that includes modern-day marsupials. Its fossils were first discovered and named by George Gaylord Simpson in 1929. Description ...'' and '' Turgidodon''.S. Bi, X. Jin, S. Li and T. Du. 2015. A new Cretaceous metatherian mammal from Henan, China. PeerJ 3:e896 A 2016 phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphadon
''Alphadon'' is an extinct genus of small, primitive mammal that was a member of the metatherians, a group of mammals that includes modern-day marsupials. Its fossils were first discovered and named by George Gaylord Simpson in 1929. Description Not much is known about the appearance of ''Alphadon'', as it is only known from teeth, a lower jaw and skull fragments. It probably grew to about and may have resembled a modern opossum. Judging from its teeth, it was likely an omnivore An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize t ..., feeding on fruits, invertebrates and possibly small vertebrates. ''Alphadon'' had a very good sense of smell and sight to track down its food, both during the day and night. Its possible whiskers could have also aided in its search for food. Taxonomy an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Didelphodon
''Didelphodon'' (from ''is''/nowiki>">/nowiki>''is''/nowiki> "opossum" tooth "tooth") is a genus of extinct metatherian mammal from the Late Cretaceous of North America. Description Although perhaps little larger than a Virginia opossum, with a skull length of and a weight of , the teeth have specialized bladelike cusps and carnassial notches, indicating that the animal was a predator; the jaws are short and massive and bear enormous, bulbous premolar teeth which appear to have been used for crushing. Analyses of a near-complete skull referred to ''Didelphodon'' show that it had an unusually high bite force quotient (i.e. bite force relative to body size) among Mesozoic mammals, suggesting a durophagous diet. However, its skull lacks the vaulted forehead of hyenas and other specialized bone-eating durophagous mammals, indicating that its diet was perhaps a mixture of hard foodstuffs (e.g. snails, bones) alongside small vertebrates and carrion; although omnivorous habits were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphadontidae
Alphadontidae was a family of mammals belonging to the clade 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 ..., the group of mammals that includes modern-day marsupials. References {{Taxonbar, from=Q11904934 Prehistoric mammal families Prehistoric metatherians ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 well as many extinct non-marsupial relatives. It is one of two groups placed in the clade Theria alongside Eutheria, which contains the placentals. Remains of metatherians have been found on all of Earth’s continents. Description Distinctive characteristics ( synapomorphies) of Metatheria include a prehensile tail, the development of a capitular tail on the humerus, the loss of tooth replacement on the second and fifth premolars, lower canines that outwardly diverge from each other, an angular process on the dentary bone—which additionally bears a posterior shelf in its masseteric fossa in Metatheria—that is equal to or greater than the length of the ramus, and the lower fifth premolar with a "very trenchant" cristid obliqua/ecto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsupial
Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a relatively undeveloped state and then nurtured within a pouch on their mother's abdomen. Extant marsupials encompass many species, including Kangaroo, kangaroos, Koala, koalas, Opossum, opossums, Phalangeriformes, possums, Tasmanian devil, Tasmanian devils, Wombat, wombats, Wallaby, wallabies, and Bandicoot, bandicoots. Marsupials constitute a clade stemming from the last common ancestor of extant Metatheria, which encompasses all mammals more closely related to marsupials than to Placentalia, placentals. The evolutionary split between placentals and marsupials occurred 125-160 million years ago, in the Middle Jurassic-Early Cretaceous period. Presently, close to 70% of the 334 extant marsupial species are concentrated on the Australian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milk River Formation
The Milk River Formation is a sandstone-dominated stratigraphic unit of the Western Canada Sedimentary Basin in southern Alberta, Canada. It was deposited in near-shore to coastal environments during Late Cretaceous (late Santonian to early Campanian) time. Based on uranium-lead dating, palynology and stratigraphic relationships, deposition occurred between ~84.1 and 83.6 Ma. The sandstones of the Virgelle Member in the centre of the formation are well-exposed at Writing-on-Stone Provincial Park in southwestern Alberta, where they bear petroglyphs carved into them by First Nations people. The formation is fossiliferous and has yielded an extensive vertebrate fauna (see Tables below), as well as fossil ammonites. In some areas it hosts shallow natural gas reservoirs.Payenberg, T.D.H., Braman, D.R. and Miall, A.D. 2003. Depositional environments and stratigraphic architecture of the Late Cretaceous and Eagle formations, southern Alberta and north-central Montana: Relationships ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pucadelphys
''Pucadelphys'' is an extinct genus of non-marsupial metatherian. The genus contains a single species, ''P. andinus''. Fossils of ''Pucadelphys'' have been found in the Santa Lucía Formation in Tiupampa in Bolivia.''Pucadelphys'' at .org Description ''Pucadelphys'' was small and likely to have eaten insects. It had a long tail, although incomplete on the best preserved fossils. It is possible that the tail was longer than (or at least as long as) its body. 17 vertebrae were preserved, and its estimated that there was 5 to 10 additional vertebrae originally. It is regarded as partially arboreal, and partially terrestrial. It may have been social, as more than ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pediomys
''Pediomys'' is an extinct genus of pediomyid marsupial from the Late Cretaceous of North America. Naming Named in 1889 for a molar from the Lance Formation by Othniel Charles Marsh, the type species ''P. elegans'' referred to its small size relative to other mammals from the late Maastrichtian formation. The species '' Protolambda hatcheri'' was moved into ''Pediomys'' by Simpson in 1927, who also named the subfamily Pediomyinae to separate ''Pediomys'' from other members of Didelphidae. Pediomyinae was then expanded by the work of Clemmens in the 1960s, who elevated the subfamily to Pediomyidae and described the new species ''P. cooki'', ''P. krejcii'', and ''P. florencae'', all from the Lance Formation. The new pediomyid species ''P. exiguus'', ''P. clemensi'', ''P. prokrejcii'' and the genus '' Aquiladelphis'' were then named by Fox and Sahni in the 1970s, with ''P. clemensi'' and ''P. prokrejcii'' from the Campanian Judith River Formation and suggested to be ancestral t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
