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Psarolepis
''Psarolepis'' (; ''psārolepis'', from Greek ψαρός 'speckled' and λεπίς 'scale') is a genus of extinct bony fish which lived around 397 to 418 million years ago ( Pridoli to Lochkovian stages). Fossils of ''Psarolepis'' have been found mainly in South China and described by paleontologist Xiaobo Yu in 1998. It is not known certainly in which group ''Psarolepis'' belongs, but paleontologists agree that it probably is a basal genus and seems to be close to the common ancestor of lobe-finned and ray-finned fishes.Benton, M. J. (2005): ''Vertebrate Palaeontology'', page 65. In 2001, paleontologist John A. Long compared ''Psarolepis'' with onychodontiform fishes and refer to their relationships. Description ''Psarolepis'' had a pair of 'parasymphysical tooth whorls', teeth which extend up at the front of the lower jaw. The head was made of several thick dermal plates and covered with deep pock-marks and large pores. Another trait is a large pectoral spine, just in f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xitun Formation
The Xitun Formation is a paleontology, palaeontological formation which is named after Xitun village in Qujing, a location in Northern and southern China, South China. This formation includes many remains of fossilized fish and plants of the Early Devonian Geologic period, period (Late Lochkovian). It was originally referred to as the Xitun Member of the Cuifengshan Formation (now the Cuifengshan Group). Fossil content Vertebrates Acanthodians Actinopterygians Chondrichthyes Jawless fish Placoderms Sarcopterygians Plants See also * List of fossil sites— ''(with link directory)'' References Geologic formations of China Devonian System of Asia Devonian China Devonian northern paleotropical deposits Paleontology in China {{China-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobe-finned Fish
Sarcopterygii (; ) — sometimes considered synonymous with Crossopterygii () — is a taxon (traditionally a class or subclass) of the bony fishes known as the lobe-finned fishes. The group Tetrapoda, a mostly terrestrial superclass including amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (with mammals being the only extant group), evolved from certain sarcopterygians; under a cladistic view, tetrapods are themselves considered a subgroup within Sarcopterygii. The known extant non-tetrapod sarcopterygians include two species of coelacanths and six species of lungfishes. Characteristics Early lobe-finned fishes are bony fish with fleshy, lobed, paired fins, which are joined to the body by a single bone. The fins of lobe-finned fishes differ from those of all other fish in that each is borne on a fleshy, lobelike, scaly stalk extending from the body. The scales of sarcopterygians are true scaloids, consisting of lamellar bone surro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiaobo Yu
Dr. Xiaobo Yu is a Chinese palaeontologist and professor on biological sciences. Yu is credited with first describing the lobe-finned fish ''Psarolepis'' romeri, a transitional species between fish and amphibians. Yu is currently a professor at Kean University Kean University () is a public university in Union Township, Union County, New Jersey, Union and Hillside, New Jersey. It is part of New Jersey's public system of higher education. Kean University was founded in 1855 in Newark, New Jersey, as th ... in Union, New Jersey. References * Yu, Xiaobo (June 1998). "A new porolepiform-like fish, Psarolepis romeri, gen. et sp. nov. (Sarcopterygii, Osteichthyes) from the Lower Devonian of Yunnan, China". Journal of Vertebrate Paleontology 18 (2): 261–274. External links University Home Page of Dr. Xiaobo Yu Chinese paleontologists Living people Kean University faculty Year of birth missing (living people) {{Paleontologist-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bony Fish
Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species. It is the largest class of vertebrates in existence today. The group Osteichthyes is divided into the ray-finned fish ( Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 425 million years old, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes. Osteichthyes can be compared to Euteleostomi. In paleontology the terms are synonymous. In ichthyology the difference is that Euteleostomi presents a cladistic view which includes the terrestrial tet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Fin
A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through convergent evolution they have independently evolved external superficial fish-like body plans adapted to their marine environments, including most numerously fish, but also mammals such as cetaceans (whales, dolphins, and porpoises), and even extinct ancient marine reptiles such as various known species of ichthyosaurs. Most species have only one dorsal fin, but some have two or three. Wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of large cetaceans to identify individuals in the field. The bony or cartilaginous bones that support the base of the dorsal fin in fish are called ''pterygiophores''. Functions The main purpose of the dorsal fin is to stabilize the animal against rollin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xishancun Formation
The Xishancun Formation is a geological formation located at Qujing, Yunnan, South China. Xishancun Formation has remains of petalichthyid and galeaspid fish and it represents the Early Devonian period (Early Lochkovian) of China. See also * List of fossil sites This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there. Many of t ... ''(with link directory)'' Geologic formations of China Devonian System of Asia Devonian China Devonian northern paleotropical deposits Paleontology in Yunnan {{China-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yulongsi Formation
The Yulongsi Formation is a palaeontological geological formation located at Qujing, in Yunnan Province of Southern China. Geology The formation is of the Pridoli epoch of the Late Silurian period, during the Paleozoic Era. See also * * * List of fossil sites This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there. Many of t ... — ''(with link directory)'' References Geologic formations of China Silurian System of Asia Silurian China Silurian paleontological sites Paleontology in Yunnan {{China-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Location Of Qujing Prefecture Within Yunnan (China)
In geography, location or place are used to denote a region (point, line, or area) on Earth's surface or elsewhere. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ambiguous boundary, relying more on human or social attributes of place identity and sense of place than on geometry. Types Locality A locality, settlement, or populated place is likely to have a well-defined name but a boundary that is not well defined varies by context. London, for instance, has a legal boundary, but this is unlikely to completely match with general usage. An area within a town, such as Covent Garden in London, also almost always has some ambiguity as to its extent. In geography, location is considered to be more precise than "place". Relative location A relative location, or situation, is described as a displacement from another site. An example is "3 miles northwest of Seattle". Absolute location An absolute locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentary
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear). It is connected to the temporal bones by the temporomandibular joints. The bone is formed prenatal development, in the fetus from a fusion of the left and right mandibular prominences, and the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, p. 59 The word "mandible" derives from the Latin word ''mandibula'', "jawbone" (literally "one used for chewing"), from ''wikt:mandere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onychodontida
Onychodontiformes (also known as Onychodontida and Struniiformes) is an order of prehistoric sarcopterygian fish that lived during the Devonian period. The onychodontiforms are generally regarded as early-diverging members of the coelacanth The coelacanths ( ) are fish belonging to the order Actinistia that includes two extant species in the genus ''Latimeria'': the West Indian Ocean coelacanth (''Latimeria chalumnae''), primarily found near the Comoro Islands off the east coast ... lineage. Phylogeny The following cladogram is adapted from Mondéjar-Fernández (2020). The study recovered Onychodontiformes as a paraphyletic group, which is shown in green: References External links Onychodontiformes at Palaeos Prehistoric lobe-finned fish Prehistoric fish orders Devonian bony fish Early Devonian first appearances Famennian extinctions Paraphyletic groups {{paleo-lobefinned-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order (biology)
Order ( la, wikt:ordo#Latin, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between Family_(biology), family and Class_(biology), class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
