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Sapeornis Chaoyangensis
''Sapeornis'' is a monotypic genus of avialan which lived during the early Cretaceous period ( late Barremian to early Aptian, roughly 125-120 mya). ''Sapeornis'' contains only one species, ''Sapeornis chaoyangensis''. Description ''Sapeornis'' was large for an early avialan, about long in life, excluding the tail feathers. The hand of ''Sapeornis'' was far more derived than that of ''Archaeopteryx''. It had three fingers, the outer ones with two and the middle one with three phalanges, and a well-fused carpometacarpus. Its arms were about half again as long as the legs, suggesting a large wing area. On the other hand, its shoulder girdle was apparently ill-adapted to flapping flight and its furcula was unusual, with a hypocleidum similar to more advanced avialans but a general anatomy even more basal than in ''Archaeopteryx''. The humerus was large and bore holes, apparently to save weight, as in the Confuciusornithidae. The skull has a handful of teeth in the upper jawt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 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 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-Manihiki-Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Ontong Java Plateau today covers an area of 1,860,000 km2. In the Indian Ocean another LIP began to form at c. 120 Ma, the Kerguelen P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confuciusornithidae
Confuciusornithidae is an extinct family of pygostylian avialans known from the Early Cretaceous, found in northern China. They are commonly placed as a sister group to Ornithothoraces, a group that contains all extant birds along with their closest extinct relatives. Confuciusornithidae contains four genera, possessing both shafted and non-shafted (downy) feathers. They are also noted for their distinctive pair of ribbon-like tail feathers of disputed function. The wing anatomy of confuciusornithids suggests an unusual flight behavior, due to anatomy that implies conflicting abilities. They possessed feathers similar to those of fast-flapping birds, which rely on quick flapping of their wings to stay aloft. At the same time, their wing anatomy also suggests a lack of flapping ability. Confuciusornithids are also noted for their beak and lack of teeth, similar to modern birds. Both predators and prey, confuciusornithid fossils have been observed with fish remains in their digestive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apomorph
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Clade analysis T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ontogeny
Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the study of the entirety of an organism's lifespan. Ontogeny is the developmental history of an organism within its own lifetime, as distinct from phylogeny, which refers to the evolutionary history of a species. Another way to think of ontogeny is that it is the process of an organism going through all of the developmental stages over its lifetime. The developmental history includes all the developmental events that occur during the existence of an organism, beginning with the changes in the egg at the time of fertilization and events from the time of birth or hatching and afterward (i.e., growth, remolding of body shape, development of secondary sexual characteristics, etc.). While developmental (i.e., ontogenetic) processes can influence sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrolith
A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In other species the rocks are ingested and pass through the digestive system and are frequently replaced. The grain size depends upon the size of the animal and the gastrolith's role in digestion. Other species use gastroliths as ballast.Rondeau, et aLarval Anurans Adjust Buoyancy in Response to Substrate IngestionCopeia: February 2005, Vol. 2005, No. 1, pp. 188-195. Particles ranging in size from sand to cobble have been documented. Etymology Gastrolith comes from the Greek γαστήρ (''gastēr''), meaning "stomach", and λίθος (''lithos''), meaning "stone". Occurrence Among living vertebrates, gastroliths are common among crocodiles, alligators, herbivorous birds, seals and sea lions. Domestic fowl require access to ''grit''. Stone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Vertebrate Paleontology And Paleoanthropology
The Institute of Vertebrate Paleontology and Paleoanthropology (IVPP; ) of China is a research institution and collections repository for fossils, including many dinosaur and pterosaur specimens (many from the Yixian Formation). As its name suggests, research is focused on both paleontological topics and those relating to human prehistory. The institution, located in Beijing, grew out of the Cenozoic Research Laboratory in 1929 and is its own institution under the Chinese Academy of Sciences. Its staff have increasingly worked internationally, participating in the China-Canada Dinosaur Project from 1986 to 1991 and authoring or coauthoring forty-five ''Nature'' and ''Science'' articles from 1999 to 2005. Notable paleontologists who have been affiliated with the IVPP include Yang Zhongjian (also known as C. C. Young), Dong Zhiming, Meemann Chang and Zhao Xijin Zhao Xijin (赵喜进; born c. 1935 died July 21, 2012) was a Chinese paleontologist notable for having named numerous di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avimimus
''Avimimus'' ( ), meaning "bird mimic" (Latin ''avis'' = bird + ''mimus'' = mimic), is a genus of oviraptorosaurian theropod dinosaur, named for its bird-like characteristics, that lived in the late Cretaceous in what is now Mongolia, around 85 to 70 million years ago. Description ''Avimimus'' was a small, bird-like dinosaur with a length of 1.5 m (5 ft). The skull was small compared to the body, though the brain and eyes were large. The size of the bones which surrounded the brain and were dedicated to protecting it are large. This is also consistent with the hypothesis that ''Avimimus'' had a proportionally large brain. The jaws of ''Avimimus'' were thought to form a parrot-like beak lacking teeth, and a thorough review of the holotype specimen's anatomy confirmed that no teeth were preserved, although a series of tooth-like projections along the tip of the premaxilla were. However, subsequently discovered specimens have been reported to preserve small prem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibula
The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is small, placed toward the back of the head of the tibia, below the knee joint and excluded from the formation of this joint. Its lower extremity inclines a little forward, so as to be on a plane anterior to that of the upper end; it projects below the tibia and forms the lateral part of the ankle joint. Structure The bone has the following components: * Lateral malleolus * Interosseous membrane connecting the fibula to the tibia, forming a syndesmosis joint * The superior tibiofibular articulation is an arthrodial joint between the lateral condyle of the tibia and the head of the fibula. * The inferior tibiofibular articulation (tibiofibular syndesmosis) is formed by the rough, convex surface of the medial side of the lower end of the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarsometatarsus
The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) and metatarsal bones (foot). Despite this, the tarsometatarsus of birds is often referred to as just the shank, tarsus or metatarsus. Tarsometatarsal fusion occurred in several ways and extents throughout bird evolution. Specifically, in Neornithes (modern birds), although the bones are joined along their entire length, the fusion is most thorough at the distal (metatarsal) end. In the Enantiornithes, a group of Mesozoic avialans, the fusion was complete at the proximal (tarsal) end, but the distal metatarsi were still partially distinct. While these fused bones are best known from birds and their relatives, avians are neither the only group nor the first to possess tarsometatarsi. In a remarkable case of parallel evolution, they were also pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomingia
''Nomingia'' is a genus of oviraptorid theropod dinosaur hailing from the Late Cretaceous Bugin Tsav Beds of Mongolia. Discovery and naming The remains, consisting of most of the vertebral column, pelvic girdle and left tibio-tarsus, holotype GIN 100/119, were found in 1994 in layers of the Nemegt Svita, dating to the Maastrichtian. They were named and described as the type species ''Nomingia gobiensis'' by Rinchen Barsbold, Barsbold, Halszka Osmólska, Mahito Watabe, Philip J. Currie, Philip Currie and Khishigjaw Tsogtbaatar in 2000 in paleontology, 2000. The etymology of the Binomial nomenclature, binomial refers to the location where the fossils were found, with the generic name mentioning the Nomingiin Gobi, a nearby part of the Gobi Desert, which is itself mentioned in the specific name (zoology), specific descriptor. A 2021 article by Funston and colleagues suggested ''Nomingia'' is a synonym of ''Elmisaurus''. Description ''Nomingia'' is a medium-sized oviraptoro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confuciusornis
''Confuciusornis'' is a genus of basal crow-sized avialan from the Early Cretaceous Period of the Yixian and Jiufotang Formations of China, dating from 125 to 120 million years ago. Like modern birds, ''Confuciusornis'' had a toothless beak, but closer and later relatives of modern birds such as ''Hesperornis'' and ''Ichthyornis'' were toothed, indicating that the loss of teeth occurred convergently in ''Confuciusornis'' and living birds. It is the oldest known bird to have a beak. It was named after the Chinese moral philosopher Confucius (551–479 BC). ''Confuciusornis'' is one of the most abundant vertebrates found in the Yixian Formation, and several hundred complete specimens have been found. History of discovery In November 1993, the Chinese paleontologists Hou Lianhai and Hu Yoaming of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) at Beijing, visited fossil collector Zhang He at his home in Jinzhou, where he showed them a fossil bird specimen t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pygostyle
Pygostyle describes a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main component of the uropygium, a structure colloquially known as the bishop's nose, parson's nose, pope's nose, or sultan's nose. This is the fleshy protuberance visible at the posterior end of a bird (most commonly a chicken or turkey) that has been dressed for cooking. It has a swollen appearance because it also contains the uropygial gland that produces preen oil. Evolution Pygostyles probably began to evolve very early in the Cretaceous period, perhaps 140 – 130 million years ago. The earliest known species to have evolved a pygostyle were members of the Confuciusornithidae. The structure provided an evolutionary advantage, as a completely mobile tail as found in species such as '' Archaeopteryx'' is detrimental to its use for flight contro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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