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Synechodontiformes
Synechodontiformes is an extinct order of prehistoric shark-like cartilaginous fish, known from the Permian to the Paleogene. They are considered to be members of Neoselachii, the group that contains modern sharks and rays. Their placement in the group is uncertain, some authors have considered them to be members of the modern shark group Galeomorphi, while others have considered them to represent a stem-group to modern sharks, with some suggesting that they are basal to the last common ancestor of modern sharks and rays. There is also disagreement about the relationships between Triassic and earlier members of the group, only known from isolated teeth, and those from the Jurassic onwards, with the similarity between the two groups possibly being superficial. The main shared characters of the group relate to teeth anatomy. The teeth roots have a distinctive pseudopolyaulacorhize vascularisation pattern, with a depression on the tooth root to where the nutritive grooves a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synechodus
''Synechodus'' is an extinct genus of shark belonging to the family Palaeospinacidae and order Synechodontiformes. It is known from 16 species primarily spanning from the Late Triassic to Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), .... The dentition is multicusped and was used for grasping.'''' Several species are known from skeletal remains, including the species ''Synechodus ungeri'' from the Late Jurassic of Germany, which shows that it was relatively short with large pectoral fins and a proportionally large head with a round snout.'''' This species is suggested to have reached a body length of . Skeletal remains are also known of the species ''Synechodus dubrisiensis'' from the Cretaceous of Europe. A skeleton of an indeterminate species is also known from the Earl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galeomorphi
Galeomorphi is a superorder of sharks. They are sometimes called galea or galean sharks. There are about 300 living species in 23 families. Galean sharks are divided into four orders: the Heterodontiformes, Orectolobiformes, Lamniformes, and Carcharhiniformes. The extinct, enigmatic Synechodontiformes are presently placed by some authors in the galeomorphs, but their taxonomic position still remains uncertain. Classification Order Heterodontiformes The bullhead sharks are a small order of basal modern sharks ( Neoselachii). All are relatively small, with the largest species being just in adult length. They are bottom feeders in tropical and subtropical waters. They appear in the fossil record in the Early Jurassic, well before any of the other galean sharks. However, they have never been common, and it is likely their origin lies even further back. There are nine living species in a single genus, ''Heterodontus'' and a single family. * Family Heterodontidae (Bullh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark
Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the Division (taxonomy), division Selachii and are the sister group to the Batoidea, Batomorphi (Batoidea, rays and skate (fish), skates). Some sources extend the term "shark" as an informal category including Extinction, extinct members of Chondrichthyes (cartilaginous fish) with a shark-like morphology, such as hybodonts. Shark-like chondrichthyans such as ''Cladoselache'' and ''Doliodus'' first appeared in the Devonian Period (419–359 million years), though some fossilized chondrichthyan-like scales are as old as the Ordovician, Late Ordovician (458–444 million years ago). The earliest confirmed modern sharks (Selachii) are known from the Early Jurassic around , with the oldest known member being ''Agaleus'', though records of true shar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoselachii
Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks ( division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by having five to seven pairs of gill slits opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch clades. The pelvic fins in males are modified to create claspers for the transfer of sperm. There is no swim bladder; instead, these fish maintain buoyancy with large livers rich in oil. The definition of the clade is unclear with respect to fossil chondrichthyans. Some authors consider it as equivalent to Neoselachii (the crown group clade including modern sharks, rays, and all other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeospinax
''Palaeospinax'' is an extinct genus of synechodontiform cartilaginous fish. Although several species have been described, the genus is considered ''nomen dubium'' because the type-specimen of the type species, ''Palaeospinax priscus'', from the Late Triassic-Early Jurassic of Europe lacks appropriate diagnostic characters to define the genus. Other species originally described as ''Synechodus ''Synechodus'' is an extinct genus of shark belonging to the family Palaeospinacidae and order Synechodontiformes. It is known from 16 species primarily spanning from the Late Triassic to Paleocene The Paleocene ( ), or Palaeocene, is a geol ...'' were transferred to the genus '' Palidiplospinax''. References Further reading * Palaeospinacidae Prehistoric cartilaginous fish genera Triassic cartilaginous fish Jurassic cartilaginous fish Cretaceous cartilaginous fish Paleocene cartilaginous fish Eocene cartilaginous fish Prehistoric fish of Europe Nomina dubia Fos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudonotidanidae
Pseudonotidanidae is an extinct family of prehistoric sharks in the order Hexanchiformes. It was formerly part of the extinct order Synechodontiformes Synechodontiformes is an extinct order of prehistoric shark-like cartilaginous fish, known from the Permian to the Paleogene. They are considered to be members of Neoselachii, the group that contains modern sharks and rays. Their placement .... References Prehistoric cartilaginous fish families Taxa described in 2004 Hexanchiformes Middle Jurassic first appearances Middle Jurassic extinctions {{paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. The Jurassic constitutes the second and middle period of the Mesozoic, Mesozoic Era as well as the eighth period of the Phanerozoic, Phanerozoic Eon and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic magmatic province, Central Atlantic Magmatic Province (CAMP). The beginning of the Toarcian Age started around 183 million years ago and is marked by the Toarcian Oceanic Anoxic Event, a global episode of Anoxic event, oceanic anoxia, ocean acidification, and elevated global temperatures associated with extinctions, likely caused by the eruption of the Kar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthacodontidae
Orthacodontidae is an extinct family of shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...s. It is disputed as to whether it belongs to the modern shark order Hexanchiformes, or the extinct order Synechodontiformes.'''' It contains two genera. Some other authors included it in Lamniformes. Species * '' Occitanodus'' Guinot, Cappetta & Adnet, 2014 ** '' Occitanodus sudrei'' Guinot, Cappetta & Adnet, 2014 * '' Sphenodus'' Agassiz, 1843 ** '' Sphenodus alpinus'' Gümbel, 1861 ** '' Sphenodus longidens'' Agassiz, 1843 ** '' Sphenodus lundgreni'' Davis, 1890 ** '' Sphenodus macer'' Quenstedt, 1852 ** '' Sphenodus nitidus'' Wagner, 1862 ** '' Sphenodus planus'' Agassiz, 1843 ** '' Sphenodus rectidens'' Emmons, 1858 ** '' Sphenodus robustidens'' Seguenza, 1900 ** '' Sphe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartilaginous Fish
Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeletons primarily composed of bone tissue. Chondrichthyes are aquatic vertebrates with paired fins, paired nares, placoid scales, conus arteriosus in the heart, and a lack of opercula and swim bladders. Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates. The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates and sawfish) and Holocephali ( chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class). Extant chondrichthyans range in size from the finless sleeper ray to the over whale shark. Anatomy Skeleton The skeleton is cartilaginous. The notochord is gradually replaced by a vertebral column during development, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexanchiformes
The Hexanchiformes Help:IPA/English, /hɛkˈsæŋkɪfɔːrmiːz/ are a primitive Order (biology), order of sharks, numbering just five extant species in two Family (biology), families, Chlamydoselachidae and Cow shark, Hexanchidae. Chlamydoselachidae are also known as frilled sharks, these sharks are very rare fishes and typically reside in deeper waters. Hexanchidae are also known as cow sharks and are the lesser known of the two types of Hexanchiformes and also reside in deep waters. Taxonomy Due to their primitive anatomy, hexanchiforms were previously considered the most Basal (phylogenetics), basal group of sharks. However, more recent phylogenetic studies indicate that while primitive, they in fact belong to the superorder Squalomorphi, which also contains Squalidae, dogfishes, angelsharks, and sawsharks, although they are thought to be the most basal member of the group. Description Hexanchiform sharks have one spineless dorsal fin located over or behind the pelvic fin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cisuralian
The Cisuralian, also known as the Early Permian, is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and dates between 298.9 ± 0.15 – 272.3 ± 0.5 Ma. In the regional stratigraphy of southwestern North America, the Cisuralian encompasses two series: the Wolfcampian (Asselian to mid-Artinskian) and Leonardian (mid-Artinskian to Kungurian). The series saw the appearance of beetles and flies and was a relatively stable warming period of about 21 million years. Name and background The Cisuralian is the first series or epoch of the Permian. The Cisuralian was preceded by the last Pennsylvanian epoch ( Gzhelian) and is followed by the Permian Guadalupian Epoch. The name "Cisuralian" was proposed in 1982, and approved by the International Subcommission on Permian Stratigraphy in 1996. The Cisuralian Epoch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antrigoulia
''Antrigoulia'' is an extinct genus of palaeospinacid shark from the Cretaceous period. It is named after a farm in the vicinity of the type locality called Mas d’Antrigoule. It is known from a single species consisting of isolated teeth from the Valanginian of France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ..., ''A. circumplicata''. The name is derived from the concentric folds on the labial side of its teeth.Guinot, Guillaume & Henri, Cappetta & Adnet, Sylvain. (2014). A rare elasmobranch assemblage from the Valanginian (Lower Cretaceous) of southern France. Cretaceous Research. 48. 54–84. 10.1016/j.cretres.2013.11.014. References Palaeospinacidae Prehistoric shark genera Monotypic prehistoric cartilaginous fish genera {{Paleo-cartilaginous-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
