|
Jiufotang Fauna
The Jiufotang Formation () 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 dating, 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 a few have been formally described and named. Ornithischians Pterosaurs Saurischians A large titanosaur is present in the formation. Enantiornithines Euornithines Non-ornithothoracean theropods Crustaceans Plants See also * Yixian Formation * List of dinosa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium–lead Dating
Uranium–lead dating, abbreviated U–Pb dating, is one of the oldest and most refined of the radiometric dating schemes. It can be used to date rocks that formed and crystallised from about 1 million years to over 4.5 billion years ago with routine precisions in the 0.1–1 percent range. The method is usually applied to zircon. This mineral incorporates uranium and thorium atoms into its crystal structure, but strongly rejects lead when forming. As a result, newly-formed zircon crystals will contain no lead, meaning that any lead found in the mineral is radiogenic. Since the exact rate at which uranium decays into lead is known, the current ratio of lead to uranium in a sample of the mineral can be used to reliably determine its age. The method relies on two separate decay chains, the uranium series from 238U to 206Pb, with a half-life of 4.47 billion years and the actinium series from 235U to 207Pb, with a half-life of 710 million years. Decay routes Uranium decays to l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Historical Biology
''Historical Biology'' is a peer-reviewed scientific journal of paleobiology. It was established in 1988, and is published by Taylor & Francis. The journal is edited by Mark T. Young. Abstracting and indexing The journal is abstracted and indexed in the following databases. According to the ''Journal Citation Reports'', the journal has a 2023 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 1.4. References External links * Biology journals Taylor & Francis academic journals Academic journals established in 1988 Paleontology journals 8 times per year journals {{paleontology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamprey
Lampreys (sometimes inaccurately called lamprey eels) are a group of Agnatha, jawless fish comprising the order (biology), order Petromyzontiformes , sole order in the Class (biology), class Petromyzontida. The adult lamprey is characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin , which may mean "stone licker" ( "to lick" + "stone"), though the etymology is uncertain. "Lamprey" is sometimes seen for the plural form. About 38 extant species of lampreys are known, with around seven known extinct species. They are classified in three families—two small families in the Southern Hemisphere (Geotriidae, Mordaciidae) and one large family in the Northern Hemisphere (Petromyzontidae). Genetic evidence suggests that lampreys are more closely related to hagfish, the only other living group of jawless fish, than they are to jawed vertebrates, forming the superclass Cyclostomi. The oldest fossils of stem-group lampreys are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weichang Manchu And Mongol Autonomous County
Weichang Manchu and Mongol Autonomous County ( zh, s=围场满族蒙古族自治县) is a Manchu and Mongol autonomous county located in far northeastern Hebei province, China. It lies under the administration of Chengde City, and is the northernmost county of the province, bordering Inner Mongolia to the north. In terms of area, it is the largest county of Hebei, occupying an area of , though, as it is located in mountainous terrain, it is rather sparsely populated, , housing 423,676 people. The area has been historically home to Manchu soldiers, and the local dialect of Mandarin is similar to that of Beijing, though there is some Northeastern influence. History The area of the county was originally grazing grounds for Mongol tribes. In the early Qing Dynasty, the Auqan, Kharchin and Onnigud Mongols gave these lands as a gift to the Kangxi Emperor, who then created the Mulan Hunting Grounds in Weichang. Thereafter, it became hunting ground for the Qing royal family, Eig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caeruleum Miraculum
''Caeruleum'' is an extinct genus of lamprey from the Lower Cretaceous Jiufotang Formation of China. The genus contains two species, ''C. miraculum'' and ''C. gracilis'', known from various specimens including complete and partial bodies. Discovery and naming The first described ''Caeruleum'' fossil material was discovered in sediments of the Jiufotang Formation near Naizi (or Naitou) Mountain in Weichang County of Chengde City, Hebei Province, China. Various lamprey specimens were found in this formation. In 2023, Weijia Huang described ''Caeruleum miraculum'' as a new genus and species of lamprey based on several fossil remains. The holotype specimen, BMM 3770, consists of a complete animal preserved on a slab and counterslab. Several additional specimens of various levels of completion were also assigned to ''Caeruleum'' as paratypes. These include BMM 3771 (an incomplete specimen with a complete tail), BMM 3772 (the posterior end of an animal with a mutilated tail), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyphalosauridae
Choristodera (from the Greek χωριστός ''chōristos'' + δέρη ''dérē'', 'separated neck') is an extinct order of semiaquatic diapsid reptiles that ranged from the Middle Jurassic, or possibly Triassic, to the Miocene (168 to 20 or possibly 11.6 million years ago). Choristoderes are morphologically diverse, with the best known members being the crocodile-like neochoristoderes such as ''Champsosaurus''. Other choristoderans had lizard-like or long necked morphologies. Choristoderes appear to have been confined to the Northern Hemisphere, having been found in North America, Asia, and Europe, and possibly also North Africa. Choristoderes are generally thought to be derived neodiapsids that are close relatives or members of Sauria. History of discovery Choristodera was erected in 1876, originally as a suborder of Rhynchocephalia by Edward Drinker Cope to contain ''Champsosaurus,'' which was described from Late Cretaceous strata of Montana by Cope in the same paper. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
