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Repenomamus Robustus
''Repenomamus'' (Latin: "reptile" (reptilis), "mammal" (mammalis)) is a genus of opossum- to badger-sized gobiconodontid mammal containing two species, ''Repenomamus robustus'' and ''Repenomamus giganticus''. Both species are known from fossils found in China that date to the early Cretaceous period, about 125-123.2 million years ago. ''R. robustus'' is one of several Mesozoic mammals for which there is good evidence that it fed on vertebrates, including dinosaurs, though it is not possible to determine if it actively hunted live dinosaurs or scavenged dead ones. ''R. giganticus'' is among the largest mammals known from the Mesozoic era. Classification and discovery The fossils were recovered from the lagerstätte of the Yixian Formation in the Liaoning province of China, which is renowned for its extraordinarily well-preserved fossils of feathered dinosaurs. They have been specifically dated to 125–123.2 million years ago, during the Early Cretaceous period. ''Repenomam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Megaannum#SI prefix multipliers, Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian-Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining Anoxic event#Cretaceous, early Aptian Oceanic Anoxic Event 1a (OAE1a) was carbon isotope dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java Plateau, Ontong Java-Manihiki Plateau, Manihiki-Hikurangi Plateau, Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus '' Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theria
Theria (; Greek: , wild beast) is a subclass of mammals amongst the Theriiformes. Theria includes the eutherians (including the placental mammals) and the metatherians (including the marsupials) but excludes the egg-laying monotremes. Characteristics Therian mammals give birth (''see viviparity'') to live young without a shelled egg. This is possible thanks to key proteins called syncytins which allow exchanges between the mother and its offspring through a placenta, even rudimental ones such as in marsupials. Genetic studies have suggested a viral origin of syncytins through the endogenization process. The marsupials and the placental mammals evolved from a common therian ancestor that gave live birth by suppressing the mother's immune system. While the marsupials continued to give birth to an underdeveloped fetus after a short pregnancy, the ancestors of placental mammals gradually evolved a prolonged pregnancy. Therian mammals no longer have the coracoid bone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graciliraptor
''Graciliraptor'' (meaning "graceful thief") is a genus of theropod dinosaur from the early Cretaceous Period. It is a microraptorine dromaeosaurid. The type species ''Graciliraptor lujiatunensis'' was first named and described in 2004 by Xu Xing and Wang Xiaoling. The generic name is derived from Latin ''gracilis'' and ''raptor''. The specific name refers to the village Lujiatun where the fossil site is located. Its fossil, holotype IVPP V 13474, was found in Beipiao, Liaoning Province, China. Description The type and only known specimen comprised part of the maxilla with some teeth, nearly complete fore and hind legs; and ten partial tail vertebrae. It is estimated to have been about long in life.Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'Winter 2010 Appendix./ref> In 2010, Gregory S. Paul gave higher estimations of one metre and 1.5 kilogrammes. ''Graciliraptor'' is extremely lightly built fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virginia Opossum
The Virginia opossum (''Didelphis virginiana''), also known as the North American opossum, is the only opossum living north of Mexico, its range extending south into Central America. It is the northernmost marsupial in the world. In the United States and Canada, it is typically called a possum, 'possum or opossum. It is a solitary nocturnal animal about the size of a domestic cat, and a successful opportunist. Opossums are familiar to many North Americans as they frequently inhabit settled areas near food sources like trash cans, pet food, compost piles, gardens or housemice. Their slow and nocturnal nature, and their attraction to roadside carrion, makes many roadkill. Name The Virginia opossum is the original animal named "opossum", a word which comes from Algonquian ''wapathemwa'', meaning "white animal". Colloquially, the Virginia opossum is frequently just called a "possum". The name ''opossum'' is applied more generally to any of the other marsupials of the families Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Khuduklestes
''Khuduklestes'' is a genus of extinct mammal of uncertain affinities from the Late Cretaceous of China. It is rather similar to the also carnivorous and taxonomically uncertain '' Oxlestes'', being slightly smaller. Description ''Khuduklestes'' is currently represented by a single specimen, a vertebral axis, known from Cenomanian deposits in the Gansu Province of China. It is rather similar to '' Oxlestes'' and is among the largest vertebral mammalian remains from the Mesozoic, indicating a cat-sized animal. Classification ''Khuduklestes'' was initially placed in Deltatheroida on the basis of its similarity to '' Oxlestes''. However, much as ''Oxlestes'', its identity as a deltatheroidean has also been questioned, and it has periodically also been considered a member of the eutherian Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials. Eutherians are dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxlestes
''Oxlestes'' is an extinct mammal from the Late Cretaceous of Asia, more specifically from the Cenomanian of Uzbekistan. A carnivorous species of uncertain affinities, it is notable for its relatively large size, being among the largest of all Mesozoic mammals.L. A. Nessov. 1982. Drevneishie mlekopitaiushchie SSSR ncient mammals of the USSR Palyentologicheskogo Obshchyestva 25:228-243 Due to the limited amount of material, it has been considered a '' nomen dubium''. Description ''Oxlestes'' is currently a monotypic genus, containing a single species, ''O. grandis''. Its specimens were recovered in the Cenomanian-aged Khodzhakul Formation of Uzbekistan. The holotype, CCMGE 6/11758, is composed of an axis vertebra, dentaries, canine teeth and a sagittal crest. The axis is relatively narrow, with a long, pointed anterior process. There are two pairs of distinct foramina anterior and posterior to the dorsal transverse suture; modern placentals only bear one. It is about 1.9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schowalteria
''Schowalteria'' is a genus of extinct mammal from the Cretaceous of Canada. It is the earliest known representative of Taeniodonta, a specialised lineage of non-placental eutherian mammals otherwise found in Paleocene and Eocene deposits. It is notable for its large size, being among the largest of Mesozoic 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 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 morphology, similar facial proportions and zygomatic arch 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 fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kollikodon
''Kollikodon'' is an extinct species of mammal, it is usually considered to be a member of Australosphenida and closely allied with monotremes, but is alternatively suggested to be a haramiyidan. It is known only from an opalised dentary fragment, with one premolar and two molars ''in situ'', as well as a referred maxillary fragment containing the last premolar and all four molars. The fossils were found in the Griman Creek Formation at Lightning Ridge, New South Wales, Australia, as was ''Steropodon''. ''Kollikodon'' lived in the Late Cretaceous period, during the Cenomanian age (99–96 million years ago). Etymology ''Kollix'' is an ancient Greek word (κολλίξ) for a bread roll. The strange teeth of ''Kollikodon'', when seen from above, resemble hot cross buns, traditionally toasted and eaten on Good Friday. Originally, Michael Archer wanted to name it "Hotcrossbunodon", but met disapproval from his associates. Description Like ''Steropodon'', ''Kollikodon'' was a rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic. The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs, pterosaurs, mosasaurs, and plesiosaurs. The Mesozoic was a time of significant tectonic, climatic, and evolutionary activity. The era witnessed the gradual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Largest Prehistoric Animals
The largest prehistoric animals include both vertebrate and invertebrate species. Many of them are described below, along with their typical range of size (for the general dates of extinction, see the link to each). Many species mentioned might not actually be the largest representative of their clade due to the incompleteness of the fossil record and many of the sizes given are merely estimates since no complete specimen have been found. Their body mass, especially, is largely conjecture because soft tissue was rarely fossilized. Generally the size of extinct species was subject to energetic and biomechanical constraints. Non-mammalian synapsids (Synapsida) Caseasaurs (Caseasauria) The herbivorous ''Alierasaurus'' was the largest caseid and the largest amniote to have lived at the time, with an estimated length around . '' Cotylorhynchus hancocki'' is also large, with an estimated length and weight of at least and more than . Edaphosaurids (Edaphosauridae) The larges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
