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Euornitheans
Euornithes (from Greek ' meaning "true birds") is a natural group which includes the most recent common ancestor of all avialans closer to modern birds than to ''Sinornis''. Description Clarke ''et al''. (2006) found that the most primitive known euornithians (the Yanornithiformes) had a mosaic of advanced and primitive features. These species retained primitive features like gastralia and a pubic symphysis. They also showed the first fully modern pygostyles, and the type specimen of ''Yixianornis'' (IVPP 13631) preserves eight elongated rectrices (tail feathers) in a modern arrangement. No earlier pygostylians are known which preserve a fan of tail feathers of this sort; instead, they showed only paired plumes or a tuft of short feathers. Classification The name Euornithes has been used for a wide variety of avialan groups since it was first named by Edward Drinker Cope in 1889. It was first defined as a clade in 1998 by Paul Sereno, who made it the group of all animals clo ... [...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] |
Jiuquanornis
''Jiuquanornis'' is an extinct genus of basal ornithuromorph dinosaur known from the Early Cretaceous Xiagou Formation of Changma Basin, Gansu Province of northwestern China. ''Jiuquanornis'' was first named by Ya-Ming Wang, Jingmai K. O'Connor, Da-Qing Li and Hai-Lu You in 2013 and the type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ... is ''Jiuquanornis niui''. References {{Taxonbar, from=Q16754002 Prehistoric euornitheans Bird genera Early Cretaceous birds of Asia Fossil taxa described in 2013 Paleontology in Gansu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pubic Symphysis
The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attaches to the pubic symphysis. In females, the pubic symphysis is close to the clitoris. In most adults it can be moved roughly 2 mm and with 1 degree rotation. This increases for women at the time of childbirth. The name comes from the Greek word ''symphysis'', meaning 'growing together'. Structure The pubic symphysis is a nonsynovial amphiarthrodial joint. The width of the pubic symphysis at the front is 3–5 mm greater than its width at the back. This joint is connected by fibrocartilage and may contain a fluid-filled cavity; the center is avascular, possibly due to the nature of the compressive forces passing through this joint, which may lead to harmful vascular disease. The ends of both pubic bones are covered by a thin layer of hyaline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastralia
Gastralia (singular gastralium) are dermal bones found in the ventral body wall of modern crocodilians and tuatara, and many prehistoric tetrapods. They are found between the sternum and pelvis, and do not articulate with the vertebrae. In these reptiles, gastralia provide support for the abdomen and attachment sites for abdominal muscles. The possession of gastralia may be ancestral for Tetrapoda and were possibly derived from the ventral scales found in animals like rhipidistians, labyrinthodonts, and ''Acanthostega'', and may be related to ventral elements of turtle plastrons. Similar, but not homologous cartilagenous elements, are found in the ventral body walls of lizards and anurans. These structures have been referred to as inscriptional ribs, based on their alleged association with the inscriptiones tendinae (the tendons that form the six pack in humans). However, the terminology for these gastral-like structures remains confused. Both types, along with sternal ribs ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinornis
''Sinornis'' is a genus of enantiornithean birds from the Lower Cretaceous Jiufotang Formation of the People's Republic of China. When it was described in 1992, this 120 million-year-old sparrow-sized skeleton represented a new avian sharing "primitive" features with '' Archaeopteryx'' as well as showing traits of modern birds. Its basal features include, but are not limited to, a flexible manus with unguals, a footed pubis, and stomach ribs. ''Sinornis'' is known only from the type species, ''Sinornis santensis''. The generic name comes from the Latin ''Sino~'', 'China' and the Greek ''ornis'', 'bird'. The specific name ''santensis'' refers to the provenance from Chaoyang county in Liaoning Province as ''Santa'', meaning "Three Temples", is a traditional name of the county. Description The holotype skeleton of ''Sinornis'', BPV 538a-b, consists of a plate and counterplate of fine-grained freshwater lake sediment as proven by numerous fish, insect, and plant remains.Sereno, P. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avialan
Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally used (see below). ''Archaeopteryx lithographica'', from the late Jurassic Period Solnhofen Formation of Germany, is possibly the earliest known avialan which may have had the capability of powered flight, though it might have been a deinonychosaur instead. Several older (but non flight-capable) avialans are known from the late Jurassic Tiaojishan Formation of China, dated to about 160 million years ago. Definition Most researchers define Avialae as branch-based clade, though definitions vary. Many authors have used a definition similar to "all theropods closer to birds than to ''Deinonychus''."Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.) (2004). ''The Dinosauria'', Second Edition. University of California Press., 861 pp. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic period (), and the Classical period (). Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical periods of the language. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regarded as a separate historical stage, although its earliest form closely resembles Attic Greek and its latest form approaches Medieval Greek. There were several regional dialects of Ancient Greek, of which Attic Greek developed into Koine. Dia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithurae
Ornithurae (meaning "bird tails" in Greek) is a natural group which includes the common ancestor of ''Ichthyornis'', ''Hesperornis'', and all modern birds as well as all other descendants of that common ancestor. Classification Ernst Haeckel coined the name in 1866 and included in the group all "true birds" with the "characteristic tail morphology of all extant birds" (translation by Jacques Gauthier). This distinguishes the group from ''Archaeopteryx'', which Haeckel placed in another new group called Sauriurae. Said simply, modern birds have short, fused pygostyle tails, while ''Archaeopteryx'' retained the long tail characteristic of non-avian theropod dinosaurs.Haeckel, Ernst (1866). ''Generelle Morphologie der Organismen''. Berlin: Georg Reimer. Gauthier converted Ornithurae into a clade, giving it a branch-based definition: "extant birds and all other taxa, such as ''Ichthyornis'' and Hesperornithes, that are closer to extant birds than is ''Archaeopteryx''". Later he and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yanornithiformes
Yanornithiformes is an order of ornithuromorph birds from the early Cretaceous Period of China. All known specimens come from the Yixian Formation and Jiufotang Formation, dating to the early Aptian age, 124.6 to 120 million years ago. The family Songlingornithidae was first named by Hou in 1997 to contain the type genus, ''Songlingornis''.Hou, (1997). ''Mesozoic Birds of China''. Taiwan Provincial Feng Huang Ku Bird Park. Taiwan: Nan Tou. 228 pp. Clarke et al. (2006) was first to find a close relationship between ''Songlingornis'' and the "yanornithids", which had been previously named to contain the similar species ''Yanornis'' and ''Yixianornis''. At least one study has found the late Cretaceous Mongolian bird '' Hollanda'' to be a member of this group. The family Yanornithidae (now Songlingornithidae Songlingornithidae is a family of basal euornitheans from the Early Cretaceous of China. All known specimens come from the Jiufotang Formation and the Yixian Formation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patagopterygiformes
Patagopterygiformes is an extinct group of large terrestrial ornithuromorphs from the Late Cretaceous of South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout .... It contains at most three genera: '' Patagopteryx'', '' Alamitornis'' and possibly '' Kuszholia''. References Prehistoric euornitheans Late Cretaceous dinosaurs of South America Cretaceous Argentina Fossils of Argentina Taxa named by José Bonaparte {{Theropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambiortiformes
Ambiortiformes is a group of prehistoric ornithuromorphs. The first species to be included, '' Ambiortus dementjevi'', lived sometime during the Barremian age between 136.4 and 125 million years agoHoltz, Thomas R. Jr. (2012). ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'Winter 2011 Appendix(PDF). in today's Mongolia. ''A. dementjevi'' belongs to the Ornithuromorpha (the group containing modern birds but not enantiornithes), according to all published cladistic analyses. However, the exact position of the species within this group has been controversial. Most analyses have found it to be either an unresolved member of the Ornithurae, or a more primitive member of Ornithuromorpha. One 2006 study, for example, found it to be more primitive than ''Yanornis'' but more advanced than '' Hongshanornis'', or even a member of the specific group containing both ''Yanornis'' and ''Yixianornis''.You, Lamanna, Harris, Chiappe, O'Conno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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