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Cimolodont
Cimolodonta is a taxon of extinct mammals that lived from the Cretaceous to the Eocene. They were some of the more derived members of the extinct order (biology), order Multituberculata. They probably lived something of a rodent-like existence until their ecological niche was assumed by true rodents. The more basal multituberculates are found in a different suborder, "Plagiaulacida", a Paraphyly, paraphyletic group containing all non cimolodontan multituberculates. Cimolodonta is apparently a natural (monophyletic) suborder. Remains have been identified from across the Northern Hemisphere. They first appeared during the Aptian extinction, Aptian, and completely replaced the more primitive plagiaulacidans by the early Late Cretaceous. The taxon is recognized as the informal Paracimexomys group and the superfamilies Djadochtatherioidea, Taeniolabidoidea, and Ptilodontoidea. Additionally, and of uncertain affinities, are the families Cimolomyidae, Boffius, Boffiidae, Eucosmodontidae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multituberculata
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, and reached a peak diversity during the Late Cretaceous and Paleocene. They eventually declined from the mid Paleocene onwards, disappearing from the known fossil record in the late Eocene. They are the most diverse order of Mesozoic mammals with more than 200 species known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism to jerboa-like hoppers. Multituberculates are usually placed as crown mammals outside either of the two main groups of living mammals—Theria, including placentals and marsupials, and MonotremataAgustí-Antón 2002, pp 3-4—but usually as closer to Theria than to monotremes. They are considered to be clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corriebaatar
''Corriebaatar'' is the type and only genus of Corriebaataridae, a family of multituberculate mammals. It contains the single species ''Corriebaatar marywaltersae'' and represents the first evidence of Australian multituberculates Fossils found in the Wonthaggi Formation date back to the Aptian stage of the Early Cretaceous. Discovery The species ''Corriebaatar marywaltersae'' was discovered in 2009 based on the discovery of a well-preserved fourth premolar found in Victoria, Australia at the Flat Rocks fossil site. It was hypothesized to represented a cimolodontan multituberculate mammal as opposed to a new, unrecognized lineage. The 2009 specimen was the holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ... and the only known remains of the species until a second specim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plagiaulacida
Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs". Plagiaulacids are a paraphyletic grouping, containing all multituberculates that lie outside of the advanced group Cimolodonta. They ranged from the Middle Jurassic Period to the early Late Cretaceous of the northern hemisphere. During the Cenomanian, they were replaced by the more advanced cimolodontans. Kielan-Jaworowska and Hurum (2001) divides “Plagiaulacida” into three informal lineages, the paulchoffatiids, the plagiaulicids, and the allodontids. Allodontid line The Allodontid line may be a superfamily, Allodontoidea. Both allodontids and paulchoffatiids (below) were among the most basal of the plagiaulacids. The Allodontid line contains: The family Allodontidae is known from two genera from the Upper Jurassic Morrison Formation of North America. The family Zofiabaataridae contains a single genus, '' Zofia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meniscoessus
''Meniscoessus'' is a genus of extinct mammal from the Upper Cretaceous Period of what is now North America. It was a member of the extinct order Multituberculata, lying within the suborder Cimolodonta and family Cimolomyidae. Taxonomy The genus ''Meniscoessus'' was named by Edward Drinker Cope in 1882. It has also been known under the following names: ''Cimolomys '' (partly); ''Dipriodon'' (Marsh 1889); ''Halodon'' (Marsh 1889); ''Oracodon'' (Marsh 1889); ''Moeniscoessus''; ''Selenacodon'' (Marsh 1889) (partly); and ''Tripriodon'' (Marsh 1889). The generic name has a complicated history. It is attributed to Cope, 1882. Later, this was joined by ''"Meniscoessus"'' (Marsh 1889). The second usage apparently related to teeth described as belonging to small carnivorous dinosaurs. These were further christened ''Dipriodon'', ''Tripriodon'' and others, including ''Triprotodon''. Close similarities were then noticed with an already established dinosaur genus, ''Paronychodon'' (Cope 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecological Niche
In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for example, by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (for example, limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey). "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another ndthe relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts". See also Chapter 2: Concepts of niches, pp. 7 ''ff'' A Grinnellian niche is determined by the habitat in which a species lives and its accompanying behavioral adaptations. An Eltonian niche emphasizes that a spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyly
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic group (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term was coined by Willi Hennig to apply to well-known taxa like Reptilia ( reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor, including all extant reptiles as well as the extinct synapsids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's North Pole. Owing to Earth's axial tilt of 23.439281°, winter in the Northern Hemisphere lasts from the December solstice (typically December 21 UTC) to the March equinox (typically March 20 UTC), while summer lasts from the June solstice through to the September equinox (typically on 23 September UTC). The dates vary each year due to the difference between the calendar year and the astronomical year. Within the Northern Hemisphere, oceanic currents can change the weather patterns that affect many factors within the north coast. Such events include El Niño–Southern Oscillation. Trade winds blow from east to west just above the equator. The winds pull surface water with them, creating currents, which flow westward due to the Coriolis e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aptian Extinction
The Aptian extinction was an extinction event of the early Cretaceous Period. It is dated to c. 116 or 117 million years ago, in the middle of the Aptian stage of the geological time scale, and has sometimes been termed the mid-Aptian extinction event as a result. It is classified as a minor extinction event, rather than a major event like the famous Cretaceous–Paleogene extinction event that brought about the end of the "age of dinosaurs" and the Mesozoic Era. The Aptian event is most readily detected among marine rather than terrestrial fossil deposits. Nonetheless, "From a palaeobotanical perspective, the Aptian Extinction Event is an episode of importance, deserving a higher status among other minor events." The Aptian event may have been causally connected with the Rahjamal Traps volcanism episode in the Bengal region of India, associated with the Kerguelen hotspot of volcanic activity. Courtillot, Vincent. ''Evolutionary Catastrophes: The Science of Mass Extinctions.'' Cambr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uzbekbaatar
''Uzbekbaatar'' is a genus of extinct mammal from the Upper Cretaceous of Uzbekistan. It was a member of the extinct order Multituberculata within the suborder Cimolodonta, though its further affinities are unclear. The genus was named by Kielan-Jaworowska Z. and Nesov L.A. in 1992 and means "Uzbek hero". The one species named by Kielan-Jaworowska and Nesov is ''Uzbekbaatar kizylkumensis'', found in the Upper Cretaceous strata of Uzbekistan. A second species was also apparently described by Averianov in 1999. References Further reading * Kielan-Jaworowska and Nesov (1992), "Multituberculate mammals from the Cretaceous of Uzbekistan", ''Acta Palaeontologica Polonica'' 37, p. 1-17. * Kielan-Jaworowska, Z. & Hurum, J.H. (2001), "Phylogeny and Systematics of multituberculate mammals", ''Paleontology'' 44, p. 389-429. * Much of this information has been derived fro Mesozoic Mammals: "basal" Cimolodonta, Cimolomyidae, Boffiidae and Kogaionidae Kogaionidae is a fam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viridomys
''Viridomys'' is a genus of extinct mammal from the Upper Cretaceous of North America. It was a member of the extinct order of Multituberculata, and lived during the Mesozoic, also known as the "age of the dinosaurs." It's within the suborder of Cimolodonta, though its further affinities are unclear. The primary species, ''Viridomys orbatus'', is known from fossils found in Campanian (Upper Cretaceous)-aged strata of the Upper Milk River Formation in Alberta, Canada. Possible remains have also been found in Dogie Mountain, Texas (United States). The Texas site is believed to be Paleocene in age. References * Fox (1971), "Early Campanian multituberculates (Mammalia: Allotheria) from the upper Milk River Formation, Alberta", ''Canadian Journal of Earth Sciences'' 8, p. 916-938. * Kielan-Jaworowska, Z. & Hurum, J.H. (2001), "Phylogeny and Systematics of multituberculate mammals", ''Paleontology'' 44, p. 389-429. * Much of this information has been derived froMesozoic Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incertae Sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty at specific taxonomic levels is indicated by ' (of uncertain family), ' (of uncertain suborder), ' (of uncertain order) and similar terms. Examples *The fossil plant '' Paradinandra suecica'' could not be assigned to any family, but was placed ''incertae sedis'' within the order Ericales when described in 2001. * The fossil ''Gluteus minimus'', described in 1975, could not be assigned to any known animal phylum. The genus is therefore ''incertae sedis'' within the kingdom Animalia. * While it was unclear to which order the New World vultures (family Cathartidae) should be assigned, they were placed in Aves ''incertae sedis''. It was later agreed to place them in a separate order, Cathartiformes. * Bocage's longbill, ''Motacilla bocagii' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
