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Liaoningosaurus Paradoxus
''Liaoningosaurus'' is an unusual genus of ankylosaurian dinosaurs from the Early Cretaceous period of China. It contains a single species, ''Liaoningosaurus paradoxus'', and is represented by two fossil specimens collected from the Yixian Formation ( Aptian age) of Liaoning. ''L. paradoxus'' was unusual among advanced ornithischian dinosaurs in that it is speculated to have hunted or scavenged, with preserved gut contents showing that it may have eaten fish. Additionally, some features of its skeleton may suggest that it was partially aquatic.Ji Q., Wu X., Cheng Y., Ten F., Wang X., and Ji Y. 2016Fish-hunting ankylosaurs (Dinosauria, Ornithischia) from the Cretaceous of China ''Journal of Geology'', 40(2) . The type species ''L. paradoxus'' was named in 2001. The generic name refers to Liaoning. The specific name refers to the confusing mix of nodosaurid and ankylosaurid features shown by the specimen. Discovery The holotype IVPP V12560 is an articulated skeleton measur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous. The Aptian partly overlaps the upper part of the Western European Urgonian Stage. The Selli Event, also known as OAE1a, was one of two oceanic anoxic events in the Cretaceous Period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma.Archangelsky, Sergio.The Ticó Flora (Patagonia) and the Aptian Extinction Event" ''Acta Paleobotanica'' 41(2), 2001, pp. 115-22. Stratigraphic definitions The Aptian was named after the small city of Apt in the Provence region of France, which is also known for its cry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jiufotang Formation
The Jiufotang Formation (Chinese: 九佛堂组, pinyin: ''jiǔfótáng zǔ'') is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see Jehol Biota). It is a member of the Jehol group. The exact age of the Jiufotang has been debated for years, with estimates ranging from the Late Jurassic to the Early Cretaceous. New uranium-lead dates reveal the formation is deposited in the Aptian stage of the Early Cretaceous. Fossils of ''Microraptor'' and ''Jeholornis'' are from the Jiufotang. Fossil content Choristoderans Fish Mammaliamorphs Several mammaliamorph specimens have been found from the Jiufotang, but only two have been formally described and named. Ornithischians Pterosaurs Saurischians A large titanosaur is present in the formation. Enantiornithines Euornithines Misc theropods See also * Yixian Formation * List of dinosaur-bearing rock for ... [...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] |
Ankylosauridae
Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Paleogene extinction event. These animals were mainly herbivorous and were obligate quadrupeds, with leaf-shaped teeth and robust, scute-covered bodies. Ankylosaurids possess a distinctly domed and short snout, wedge-shaped osteoderms on their skull, scutes along their torso, and a tail club. Ankylosauridae is exclusively known from the northern hemisphere, with specimens found in western North America, Europe, and East Asia. The first discoveries within this family were of the genus ''Ankylosaurus'', by Peter Kaiser and Barnum Brown in Montana in 1906. Brown went on to name Ankylosauridae and the subfamily Ankylosaurinae in 1908. Anatomy Ankylosaurids are stout, solidly built, armoured dinosaurs. They possess accessory ossifications on c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nodosauridae
Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period in what is now North America, South America, Europe, and Asia. Description Nodosaurids, like their close relatives the ankylosaurids, were heavily armored dinosaurs adorned with rows of bony armor nodules and spines (osteoderms), which were covered in keratin sheaths. All nodosaurids, like other ankylosaurians, were medium-sized to large, heavily built, quadrupedal, herbivorous dinosaurs, possessing small, leaf-shaped teeth. Unlike ankylosaurids, nodosaurids lacked mace-like tail clubs, instead having flexible tail tips. Many nodosaurids had spikes projecting outward from their shoulders. One particularly well-preserved nodosaurid "mummy", known as the Suncor nodosaur (''Borealopelta markmitchelli''), preserved a nearly complete set of armor in life position, as well as the keratin covering and mineralized remains of the underlying skin, which indicate reddish dorsal pigmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victoria Arbour
Victoria Megan Arbour is a Canadian evolutionary biologist and vertebrate palaeontologist at Royal BC Museum, where she is Curator of Palaeontology. An "expert on the armoured dinosaurs known as ankylosaurs", Arbour analyzes fossils and creates 3-D computer models. She named the possible pterosaur '' Gwawinapterus'' from Hornby Island, and a partial ornithischian dinosaur from Sustut Basin, British Columbia (now named ''Ferrisaurus''), and has participated in the naming of the ankylosaurs ''Zuul'', ''Zaraapelta'', ''Crichtonpelta'', and ''Ziapelta''. Early life and education Born in 1983, Arbour is from Halifax, Nova Scotia. Her mother, a math teacher, and father, a soil scientist, supported her science interests. Arbour completed a B.Sc. Honours Thesis supervised by Milton Graves, ''An ornithischian dinosaur from the Sustut Basin, British Columbia, Canada'', and graduated from Dalhousie University in 2006. She completed her master's thesis, ''Evolution, biomechanics, and func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhombus
In plane Euclidean geometry, a rhombus (plural rhombi or rhombuses) is a quadrilateral whose four sides all have the same length. Another name is equilateral quadrilateral, since equilateral means that all of its sides are equal in length. The rhombus is often called a "diamond", after the diamonds suit in playing cards which resembles the projection of an octahedral diamond, or a lozenge, though the former sometimes refers specifically to a rhombus with a 60° angle (which some authors call a calisson after the French sweet – also see Polyiamond), and the latter sometimes refers specifically to a rhombus with a 45° angle. Every rhombus is simple (non-self-intersecting), and is a special case of a parallelogram and a kite. A rhombus with right angles is a square. Etymology The word "rhombus" comes from grc, ῥόμβος, rhombos, meaning something that spins, which derives from the verb , romanized: , meaning "to turn round and round." The word was used both by Eucl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexagonal
In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has Schläfli symbol and can also be constructed as a truncated equilateral triangle, t, which alternates two types of edges. A regular hexagon is defined as a hexagon that is both equilateral and equiangular. It is bicentric, meaning that it is both cyclic (has a circumscribed circle) and tangential (has an inscribed circle). The common length of the sides equals the radius of the circumscribed circle or circumcircle, which equals \tfrac times the apothem (radius of the inscribed circle). All internal angles are 120 degrees. A regular hexagon has six rotational symmetries (''rotational symmetry of order six'') and six reflection symmetries (''six lines of symmetry''), making up the dihedral group D6. The longest diagonals of a regular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoderm
Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amphibians), various groups of dinosaurs (most notably ankylosaurs and stegosaurians), phytosaurs, aetosaurs, placodonts, and hupehsuchians (marine reptiles with possible ichthyosaur affinities). Osteoderms are uncommon in mammals, although they have occurred in many xenarthrans (armadillos and the extinct glyptodonts and mylodontid and scelidotheriid ground sloths). The heavy, bony osteoderms have evolved independently in many different lineages. The armadillo osteoderm is believed to develop in subcutaneous dermal tissues. These varied structures should be thought of as anatomical analogues, not homologues, and do not necessarily indicate monophyly. The structures are however derived from scutes, common to all classes of amniotes and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liaoningosaurus
''Liaoningosaurus'' is an unusual genus of ankylosaurian dinosaurs from the Early Cretaceous period of China. It contains a single species, ''Liaoningosaurus paradoxus'', and is represented by two fossil specimens collected from the Yixian Formation (Aptian age) of Liaoning. ''L. paradoxus'' was unusual among advanced ornithischian dinosaurs in that it is speculated to have hunted or scavenged, with preserved gut contents showing that it may have eaten fish. Additionally, some features of its skeleton may suggest that it was partially aquatic.Ji Q., Wu X., Cheng Y., Ten F., Wang X., and Ji Y. 2016Fish-hunting ankylosaurs (Dinosauria, Ornithischia) from the Cretaceous of China ''Journal of Geology'', 40(2) . The type species ''L. paradoxus'' was named in 2001. The generic name refers to Liaoning. The specific name refers to the confusing mix of nodosaurid and ankylosaurid features shown by the specimen. Discovery The holotype IVPP V12560 is an articulated skeleton measuring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachycephalosauria
Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, most pachycephalosaurs lived during the Late Cretaceous Period, dating between about 85.8 and 65.5 million years ago. They are exclusive to the Northern Hemisphere, all of them being found in North America and Asia. They were all bipedal, herbivorous/omnivorous animals with thick skulls. Skulls can be domed, flat, or wedge-shaped depending on the species, and are all heavily ossified. The domes were often surrounded by nodes and/or spikes. Partial skeletons have been found of several pachycephalosaur species, but to date no complete skeletons have been discovered. Often isolated skull fragments are the only bones that are found. Candidates for the earliest known pachycephalosaur include ''Ferganocephale adenticulatum'' from Middle Jurassic Period strata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
