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Kryoryctes Cadburyi
''Kryoryctes'' is a genus of prehistoric monotreme mammal from the Early Cretaceous (Albian) Eumeralla Formation of Victoria (Australia), Victoria, Australia from the Otway Group of Dinosaur Cove. It is known only from a partial right humerus, estimated at 106 million years old, and contains one species, ''K. cadburyi''. The holotype, NMV P20894, was described in 2005 and is currently housed in the Museums Victoria Palaeontological Collection. Etymology The genus name derives from Greek "kryo", meaning low temperature, in reference to the seasonal coldness common to the paleoecology, paleo-environment of Dinosaur Cove, and from the Greek "oryktes", meaning one who digs, referring to the robust humerus from which a fossorial lifestyle has been inferred. The species is named in honour of Cadbury chocolates, referring to the dark colour of the holotype, as well as for the "recognition and support provided" by Cadbury chocolates during the field work that resulted in discovery of the ... [...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 Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoecology
Paleoecology (also spelled palaeoecology) is the study of interactions between organisms and/or interactions between organisms and their environments across geologic timescales. As a discipline, paleoecology interacts with, depends on and informs a variety of fields including paleontology, ecology, climatology and biology. Paleoecology emerged from the field of paleontology in the 1950s, though paleontologists have conducted paleoecological studies since the creation of paleontology in the 1700s and 1800s. Combining the investigative approach of searching for fossils with the theoretical approach of Charles Darwin and Alexander von Humboldt, paleoecology began as paleontologists began examining both the ancient organisms they discovered and the reconstructed environments in which they lived. Visual depictions of past marine and terrestrial communities have been considered an early form of paleoecology. Overview of paleoecological approaches * Classic paleoecology uses data from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, which includes the most recent common ancestor of all modern birds, and all of its extant or extinct descendants. The concept was developed by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms relative to their extinct relatives in his "Die Stammesgeschichte der Insekten", and the "crown" and "stem" group terminology was coined by R. P. S. Jefferies in 1979. Though formulated in the 1970s, the term was not commonly used until its reintroduction in 2000 by Graham Budd and Sören Jensen. Contents of the crown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echidna
Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the only surviving members of the order Monotremata. The diet of some species consists of ants and termites, but they are not closely related to the true anteaters of the Americas, which (along with sloths and armadillos) are xenarthrans. Echidnas live in Australia and New Guinea. Echidnas evolved between 20 and 50 million years ago, descending from a platypus-like monotreme. This ancestor was aquatic, but echidnas adapted to life on land. Etymology Echidnas are named after Echidna, a creature from Greek mythology who was half-woman, half-snake, as the animal was perceived to have qualities of both mammals and reptiles. An alternative explanation is a confusion with . Physical characteristics Echidnas are medium-sized, solitar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotrematum
''Monotrematum sudamericanum'' is an extinct monotreme species from the Paleocene ( Peligran) Salamanca Formation in Patagonia, Argentina. It is the only monotreme found outside Oceania. Taxonomy A species described in 1992 and assigned to a new genus ''Monotrematum'' as the type. It is currently the only known species of the genus. The authors compared their fossil material to the genus '' Obdurodon'', ornithorhynchid species first discovered at Australian fossil sites in 1975. Description ''Monotrematum sudamericanum'' is known only from two lower and one upper platypus-like teeth. It is the only known non-Australasian ornithorhynchid. The main difference, apart from continent and age, is its size: the teeth of ''Monotrematum'' are around twice as large as those of other similar species in the related genus '' Obdurodon''. The teeth of ''M. sudamericanum'' presently reside in the collections of Museo de La Plata and Museo Paleontológico Egidio Feruglio The Museum of Pale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teinolophos
''Teinolophos'' is a prehistoric species of monotreme, or egg-laying mammal, from the Teinolophidae. It is known from four specimens, each consisting of a partial lower jawbone collected from the Wonthaggi Formation at Flat Rocks, Victoria, Australia. It lived during the late Barremian age of the Lower Cretaceous. The species name honours the artist Peter Trusler. The genus name, ''Teinolophos'', means "extended ridge", a reference to its tooth structure. Originally, ''Teinolophos'' was thought to be a eupantothere. Further research revealed similarities to '' Steropodon'', except in size: the animal was around 10 cm long. It is often listed as a steropodontid, though it may be more basal.Thomas H. Rich, James A. Hopson, Pamela G. Gill, Peter Trusler, Sally Rogers-Davidson, Steve Morton, Richard L. Cifelli, David Pickering, Lesley Kool, Karen Siu, Flame A. Burgmann, Tim Senden, Alistair R. Evans, Barbara E. Wagstaff, Doris Seegets-Villiers, Ian J. Corfe, Timothy F ... [...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 re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obdurodon
''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species ''Obdurodon insignis'', plus ''Obdurodon dicksoni'' and ''Obdurodon tharalkooschild''. The species appeared much like their modern day relative the platypus, except adults retained their molar teeth, and unlike the platypus, which forages on the lakebed, they may have foraged in the water column or surface. Taxonomy The ''Obdurodon insignis'' holotype specimen, SAM P18087, a tooth, was uncovered in 1971 from the Etadunna Formation in the Tirari Desert of South Australia. The second specimen discovered there, AMNH 97228, is an upper right molar. In total, 4 specimens are reported, dating from the Oligocene to the Pliocene. The holotype tooth was placed into the newly erected genus ''Obdurodon'' upon description in 1975 by American palaeontologists Michael O. Woodburne and Richard H. Ted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steropodon
''Steropodon'' is a genus of prehistoric monotreme, or egg-laying mammal. It contains a single species, ''Steropodon galmani'', that lived about 105 to 93.3 million years ago (mya) in the Early to Late Cretaceous period. It is one of the oldest monotremes discovered, and is one of the oldest Australian mammal discoveries. Taxonomy The dentition of ''Steropodon'' is somewhat similar to that of therians—the placentals and the marsupials—specifically the presence of the tribosphenic molar tooth which was thought to be exclusive to therians since the Cretaceous. This, along with the tribosphenic molar discoveries of monotreme-relatives '' Ausktribosphenos'' and '' Ambondro mahabo'' of which the latter evolved in the Jurassic, led to the conclusion that the molar evolved independently in the two lineages. This inspired the creation of the subclasses Australosphenida—the monotremes and extinct relatives—and Tribosphenida—placentals and marsupials. However, given this cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olecranon Fossa
The olecranon fossa is a deep triangular depression on the posterior side of the humerus, superior to the trochlea. It provides space for the olecranon of the ulna during extension of the forearm. Structure The olecranon fossa is located on the posterior side of the distal humerus. The joint capsule of the elbow attaches to the humerus just proximal to the olecranon fossa. Function The olecranon fossa provides space for the olecranon of the ulna during extension of the forearm, from which it gets its name. Other animals The olecranon fossa is present in various mammals, including dogs The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relativ .... Additional images File:Slide1bgbg.JPG, Elbow joint. Deep dissection. Posterior view. File:Slide2bgbg.JPG, Elbow joint. Deep dissec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of the forearm as the little finger. It runs parallel to the radius, the other long bone in the forearm. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore, the radius is considered to be the larger of the two. Structure The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. It is broader close to the elbow, and narrows as it approaches the wrist. Close to the elbow, the ulna has a bony process, the olecranon process, a hook-like structure that fits into the olecranon fossa of the humerus. This prevents hyperextension and forms a hinge joint with the trochlea of the humerus. There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulcus (morphology)
In biological morphology and anatomy, a sulcus (pl. ''sulci'') is a furrow or fissure (Latin ''fissura'', plural ''fissurae''). It may be a groove, natural division, deep furrow, elongated cleft, or tear in the surface of a limb or an organ, most notably on the surface of the brain, but also in the lungs, certain muscles (including the heart), as well as in bones, and elsewhere. Many sulci are the product of a surface fold or junction, such as in the gums, where they fold around the neck of the tooth. In invertebrate zoology, a sulcus is a fold, groove, or boundary, especially at the edges of sclerites or between segments. In pollen a grain that is grooved by a sulcus is termed sulcate. Examples in anatomy Liver *Ligamentum teres hepatis fissure *Ligamentum venosum fissure * Portal fissure, found in the under-surface of the liver * Transverse fissure of liver, found in the lower surface of the liver * Umbilical fissure, found in front of the liver Lung *Azygos fissure, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
