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Gobiconodont
Gobiconodonta is an order of extinct mammals known from the Early Jurassic (such as '' Huasteconodon'') to early Late Cretaceous. They are generally held to be part of Eutriconodonta. Biology Like many other non-therian mammals, gobiconodonts retained classical mammalian synapomorphies like epipubic bones (and likely the associated reproductive constrictions), venomous spurs and sprawling limbs. However, the forelimb and shoulder anatomy of at least some species like ''Jeholodens'' are similar to those of therian mammals, though the hindlimbs remain more conservative. Gobiconodonts had a modern ear anatomy, the main difference from therians being that the ear ossicles were still somewhat connected to the jaw via the Meckel's cartilage. Some information on gobiconodont soft-tissues can be seen in ''Spinolestes'', which was very well preserved, showing evidence of fur and internal organs. ''Spinolestes'' shows hair similar to that of modern mammals, with compound hair follicles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gobiconodontidae
Gobiconodontidae is a family of extinct mammals that ranged from the mid-Jurassic to the early Late Cretaceous, though most common during the Early Cretaceous. The Gobiconodontids form a diverse lineage of carnivorous non-therian mammals, and include some of the best preserved Mesozoic mammal specimens. Biology Like many other non-therian mammals, gobiocontids retained classical mammalian synapomorphies like epipubic bones (and likely the associated reproductive constrictions), venomous spurs and sprawling limbs. Through '' Spinolestes'' we also know that they had fur similar to that of modern mammals, with compound hair follicles with primary and secondary hairs. ''Spinolestes'' also possesses a clear diaphragm like modern mammals, as well as spines, dermal scutes and an ossified Meckel's cartilage. Furthermore, it may also display signs of dermatophytosis, suggesting that gobiconodontids, like modern mammals, were vulnerable to this type of fungal infection. Gobiconodontid d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Repenomamus
''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. ''Repenomamu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutriconodonta
Eutriconodonta is an order of early mammals. Eutriconodonts existed in Asia, Africa, Europe, North and South America during the Jurassic and the Cretaceous periods. The order was named by Kermack ''et al.'' in 1973 as a replacement name for the paraphyletic Triconodonta. Traditionally seen as the classical Mesozoic small mammalian insectivores, discoveries over the years have shown them to be among the best examples of the diversity of mammals in this time period, including a vast variety of bodyplans, ecological niches and locomotion methods. Classification "Triconodonta" had long been used as the name for an order of early mammals which were close relatives of the ancestors of all present-day mammals, characterized by molar teeth with three main cusps on a crown that were arranged in a row. The group originally included only the family Triconodontidae and taxa that were later assigned to the separate family Amphilestidae, but was later expanded to include other taxa such as ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gobiconodon
''Gobiconodon'' is an extinct genus of carnivorous mammal from the Middle Jurassic to Early Cretaceous. It weighed , had a skull of in length, and had in presacral body length. It was one of the largest mammals known from the Mesozoic. Like other gobiconodontids, it possesses several speciations towards carnivory, such as shearing molar teeth, large canine-like incisors and powerful jaw and forelimb musculature, indicating that it probably fed on vertebrate prey; rather uniquely among predatory mammals and other eutriconodonts, the lower canines were vestigial, with the first lower incisor pair having become massive and canine-like. Like the larger '' Repenomamus'' there might be some evidence of scavenging Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ....Zofia Kielan-Jawor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinolestes
''Spinolestes'' is an extinct mammal genus from the Early Cretaceous of Spain. A gobiconodontid eutriconodont, it is notable for the remarkable degree of preservation, offering profound insights to the biology of non-therian mammals.Thomas Martin, Jesús Marugán-Lobón, Romain Vullo, Hugo Martín-Abad, Zhe-Xi Luo & Angela D. Buscalioni (2015). A Cretaceous eutriconodont and integument evolution in early mammals. Nature 526, 380–384. doi:10.1038/nature14905 Description ''Spinolestes holotype, MCCMLH30000A', hails from Las Hoyas, Spain. The living animal was about 24 centimeters long and weighted somewhere between 50 and 70 grams. As a Konservat-Lagerstätten specimen, it is famous for being remarkably well preserved, including not only the skeleton but also multiple soft tissues like fur, skin, internal organs and ears (both external and internal), a rarity among Mesozoic mammals. Besides soft-tissues, ''Spinolestes'' is also remarkable for its xenarthrous vertebrae, converg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venomous Mammal
Venomous mammals are animals of the class Mammalia that produce venom, which they use to kill or disable prey, to defend themselves from predators or conspecifics or in agonistic encounters. Mammalian venoms form a heterogeneous group with different compositions and modes of action, from three orders of mammals: Eulipotyphla, Monotremata, and Chiroptera. It has been proposed that some members of a fourth order, Primates, are venomous. To explain the rarity of venom delivery in Mammalia, Mark Dufton of the University of Strathclyde has suggested that modern mammalian predators do not need venom because they are able to kill quickly with their teeth or claws, whereas venom, no matter how sophisticated, requires time to disable prey. In spite of the rarity of venom among extant mammals, venom may be an ancestral feature among mammals, as venomous spurs akin to those of the modern platypus are found in most non-therian Mammaliaformes groups.Jørn H. Hurum, Zhe-Xi Luo, and Zofia K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla ( hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla (cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, tog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Web
A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Another name for food web is consumer-resource system. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs. To maintain their bodies, grow, develop, and to reproduce, autotrophs produce organic matter from inorganic substances, including both minerals and gases such as carbon dioxide. These chemical reactions require energy, which mainly comes from the Sun and largely by photosynthesis, although a very small amount comes from bioelectrogenesis in wetlands, and mineral electron donors in hydrothermal vents and hot springs. These trophic levels are not binary, but form a gradient that includes complete autotrophs, which obtain their sole source of carbon from the atmosphere, mixotrophs (such as carnivorous plants), which are autotrophic organisms th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deltatheroida
Deltatheroida is an extinct group of basal metatherians that were distantly related to modern marsupials. The majority of known members of the group lived in the Cretaceous; one species, '' Gurbanodelta kara'', is known from the late Paleocene ( Gashatan) of China. Their fossils are restricted to Central Asia and North America. This order can be defined as all metatherians closer to '' Deltatheridium'' than to Marsupialia. These mammals possessed primitive tritubercular (three-cusped) lower molars that were not tribosphenic. This is awkward because tribosphenic molars are commonly found in most therian mammals (there exist some exceptions such as anteaters and some whales, which have no teeth at all). When they were first identified in the 1920s, they were believed to be placentals and possible ancestors of the "creodonts" (a polyphyletic group of extinct carnivorous mammals from the Paleogene and Miocene), but this was later disproven. Nonetheless, deltatheroideans do conver ... [...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. There are three extant subclasses of mammals, one being metatherians: # monotremes: egg laying mammals like the platypus and the echidna, #metatheria: marsupials, which includes three American orders ( Didelphimorphia, Paucituberculata and Microbiotheria) and four Australasian orders ( Notoryctemorphia, Dasyuromorphia, Peramelemorphia and Diprotodontia), and the #eutherians: placental mammals, consisting of four superorders divided into 21 orders. Metatherians belong to a subgroup of the northern tribosphenic mammal clade or Boreosphenida. They differ from all other mammals in certain morphologies like their dental formula, which includes about five upper and four lower incisors, a canine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanocuris
''Nanocuris'' is an extinct genus of Deltatheridiidae from the Cretaceous of Canada (Saskatchewan) and United States (Wyoming - Lance Formation).R. C. Fox, C. S. Scott, and H. N. Bryant. 2007. A new, unusual therian mammal from the Upper Cretaceous of Saskatchewan, Canada. Cretaceous Research 28(5):821-829. Initially, it was classified in a proper family, Nanocuridae, in the clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ... Eutheria, but a reanalysis of a new specimen revealed a delthatheroid affinity of the genus.G. P. Wilson and J. A. Riedel. 2010New specimen reveals deltatheroidan affinities of the North American Late Cretaceous mammal Nanocuris Journal of Vertebrate Paleontology 30(3):872-884 References Prehistoric metatherians Cretaceous mammals Cretaceous mam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.1 Ma. Certain rocks of marine origin of this age in Europe are called "Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias limestone from South Wales was used throughout North Devon/North Cornwall as it conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
