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Polyodontidae
Paddlefish (family Polyodontidae) are a family of ray-finned fish belonging to order Acipenseriformes, and one of two living groups of the order alongside sturgeons (Acipenseridae). They are distinguished from other fish by their elongated rostra, which are thought to enhance electroreception to detect prey. Paddlefish have been referred to as " primitive fish" because the Acipenseriformes are among the earliest diverging lineages of ray-finned fish, having diverged from all other living groups over 300 million years ago. Both living and fossil paddlefish are found almost exclusively in North America and China. Eight species are known: Six of those species are extinct, and known only from fossils (five from North America, one from China), one of the extant species, the American paddlefish (''Polyodon spathula''), is native to the Mississippi River basin in the U.S. The other is the Chinese paddlefish (''Psephurus gladius''), which was declared extinct in 2022 following a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Paddlefish
The Chinese paddlefish (''Psephurus gladius''; : literal translation: "white sturgeon"), also known as the Chinese swordfish, is an Extinction, extinct species of fish that was formerly native to the Yangtze and Yellow River basins in China. With records of specimens over and possibly in length, it was one of the List of largest fish, largest species of freshwater fish. It was the only species in the genus ''Psephurus'' and one of two Holocene, recent species of paddlefish (Polyodontidae), the other being the American paddlefish (''Polyodon spathula''). It was an anadromous species, meaning that it spent part of its adult life at sea, while migrating upriver to Spawn (biology), spawn. The Chinese paddlefish was officially declared extinct in 2022, with an estimated time of extinction to be by 2005, and no later than 2010, although it had become functionally extinct by 1993. The main cause of its extinction was the construction of the Gezhouba Dam, Gezhouba and Three Gorges Dam, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Paddlefish
The American paddlefish (''Polyodon spathula''), also known as a Mississippi paddlefish, spoon-billed cat, or spoonbill, is a species of ray-finned fish. It is the last extant taxon, living species of paddlefish (Polyodontidae). This family is most closely related to the sturgeons; together they make up the order (biology), order Acipenseriformes, which are one of the most Basal (phylogenetics), primitive living groups of ray-finned fish. Fossil records of other paddlefish species date back 125 million years to the Early Cretaceous, with records of ''Polyodon'' extending back 65 million years to the early Paleocene. The American paddlefish is a smooth-skinned freshwater fish with an almost entirely cartilage, cartilaginous skeleton and a paddle-shaped rostrum (anatomy), rostrum (snout), which extends nearly one-third its body length. It has been referred to as a freshwater shark because of its heterocercal tail or caudal fin resembling that of sharks, though it is not closely rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleopsephurus
''Paleopsephurus'' is an extinct genus of paddlefish (Polyodontidae). At present the genus contains the single species ''Paleopsephurus wilsoni''. The genus is known from the Late Cretaceous (Maastrichtian) aged Hell Creek Formation of Montana. History and classification The genus was described from three partial specimens currently residing in the collections of the University of Michigan Museum of Paleontology in Ann Arbor, Michigan, USA. Specimen number '' 22206 U.M.'' is a complete and well preserved skull with some denticles, pectoral girdle and pectoral fins. The second and third specimens were found in a block of matrix from the same location as ''2226 U.M.''. Specimen ''22207 U.M.'' is a portion of the caudal region of a paddlefish, while ''22208 U.M.'' is a partial shoulder with associated pectoral fin. While the specimens were found close to each other, it is impossible to determine if they represent a single individual, and as such were described as three separ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acipenseriformes
Acipenseriformes is an order (biology), order of basal (phylogenetics), basal Actinopterygii, ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct family (biology), families Chondrosteidae and Peipiaosteidae. They are the second earliest diverging group of living ray-finned fish after the bichirs. Despite being early diverging, they are highly Primitive (phylogenetics), derived, having only weakly Ossification, ossified skeletons that are mostly made of cartilage, and in modern representatives highly modified skulls. Description The axial skeleton of Acipenseriformes is only partially ossified, with the majority of the bones being replaced with cartilage. The notochord, usually only found in fish embryos, is unconstricted and retained throughout life. The premaxilla and maxilla bones of the skull present in other vertebrates have been lost. While larvae and early juvenile acipenseriforms have teeth, the adult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossopholis
''Crossopholis'' is an extinct fish known from the early Eocene (Ypresian) of North America, approximately 52 million years ago. It is a close relative of the contemporary American paddlefish, belonging to the paddlefish family Polyodontidae. History of discovery First described by Edward Drinker Cope in 1883, the first specimen consisted of an incomplete section of the fish's body and tail. In 1886, a partial skull was recovered by Cope. A nearly complete fossil wasn't recorded until 1980. This was due, in part, to the comparative rarity of the fossil as well as the similarities to other species found within the site. Classification A member of the family Polyodontidae, ''Crossopholis'' is most closely related to the American paddlefish. ''Crossopholis'' means "fringed scales"; a reference to the thousands of tiny (less than 0.5mm) scales which covered the body of the animal. Relationships of recent and fossil paddlefish genera, after Grande ''et al.'' (2002). Paleobiology T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sturgeon
Sturgeon (from Old English ultimately from Proto-Indo-European language, Proto-Indo-European *''str̥(Hx)yón''-) is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier Acipenseriformes, acipenseriform fish, which date back to the Early Jurassic period, some 174 to 201 million years ago. They are one of two living families of the Acipenseriformes alongside paddlefish (Polyodontidae). The family is grouped into five genera: ''Acipenser'', ''Huso'', ''Scaphirhynchus,'' ''Sinosturio'', and ''Pseudoscaphirhynchus''. Two species (''Adriatic sturgeon, H. naccarii'' and ''Dabry's sturgeon, S. dabryanus'') may be extinct in the wild, and one (''Syr Darya sturgeon, P. fedtschenkoi'') may be entirely extinct. Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. A Maastrichtian-age fossil found i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapsephurus
''Parapsephurus'' is an extinct genus of paddlefish in the family Polyodontidae. Currently the only known species in this genus is the type species, ''Parapsephurus willybemisi.'' ''P. willybemisi'' is known a nearly complete specimen from the Tanis locality of the Hell Creek Formation in North Dakota, USA, which dates to the late Maastrichtian stage of the Late Cretaceous, approximately 66 million years ago. The name ''Parapsephurus'' refers to the similarities between the short gill arches of this genus and the more recently extinct paddlefish '' Psephurus,'' also known as the Chinese paddlefish. The type species, ''P. willybemisi'', is named in honor of William E. Bemis, a professor of ecology and evolutionary biology and curator of fishes at Cornell University, who has conducted extensive research on paddlefish. The rostrum of the holotype specimen is around in length, with a total body length of around . The species is placed in the clade Polyodonti, which includes all pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protopsephurus
''Protopsephurus'' is an extinct genus of paddlefish containing the single species ''Protopsephurus liui,'' known from the Yixian, Jiufotang and Huajiying formations in Liaoning, northern China from the Barremian to Aptian ages of the Early Cretaceous period around 125-120 million years ago. It is currently the oldest and most basal paddlefish known. Description The species is known from numerous specimens ranging up to about long. The snout is shorter than that in any other known paddlefish, and is more sturgeon-like. The morphology of the skull roof is also more archaic than any other paddlefish. The axial skeleton is poorly ossified. Like other extinct polyodontids, it also has tiny non-interlocking scales approximately 1 mm in diameter called denticles that cover the trunk, which bear a fringe of spikes. Diet ''Protopsephurus'' is thought to have been piscivorous, feeding on smaller fish. One adult specimen of ''Protopsephurus'' has been observed with a specimen of '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piscivores
A piscivore () is a carnivorous animal that primarily eats fish. Fish were the diet of early tetrapod evolution (via water-bound amphibians during the Devonian period); insectivory came next; then in time, the more terrestrially adapted reptiles and synapsids evolved herbivory A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n .... Almost all predatory fish (most sharks, tuna, billfishes, Esox, pikes etc.) are obligated piscivores. Some non-piscine aquatic animals, such as whales, sea lions, and crocodilians, are not completely piscivorous; often also preying on invertebrates, marine mammals, waterbirds and even wading land animals in addition to fish, while others, such as the bulldog bat and gharial, are strictly dependent on fish for food. Some creatures, including cnidarians, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocercal
Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only by muscles. Fish fins are distinctive anatomical features with varying structures among different clades: in ray-finned fish (Actinopterygii), fins are mainly composed of bony spines or rays covered by a thin stretch of scaleless skin; in lobe-finned fish (Sarcopterygii) such as coelacanths and lungfish, fins are short rays based around a muscular central bud supported by jointed bones; in cartilaginous fish (Chondrichthyes) and jawless fish (Agnatha), fins are fleshy " flippers" supported by a cartilaginous skeleton. Fins at different locations of the fish body serve different purposes, and are divided into two groups: the midsagittal ''unpaired fins'' and the more laterally located ''paired fins''. Unpaired fins are predominant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 Megaannum#SI prefix multipliers, 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 Anoxic event#Cretaceous, early Aptian Oceanic Anoxic Event 1a (OAE1a) was 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 Plateau, Ontong Java-Manihiki Plateau, Manihiki-Hikurangi Plateau, Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Onto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have complex internal and external structures. They are lightweight yet strong and hard and serve multiple functions. Bone tissue (osseous tissue), which is also called bone in the uncountable sense of that word, is hard tissue, a type of specialised connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralisation of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
