Plagioolithus
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Plagioolithus
''Plagioolithus'' is an oogenus of fossil egg. It is from the Early Cretaceous of Japan. It was probably laid by a bird, making it the oldest known fossil bird egg. Description ''Plagioolithus'' is most notable for having a three-layered eggshell. This trait is widespread in modern birds, but is very rare among Mesozoic fossil eggs. No complete eggs have been found, so the size and shape of ''Plagioolithus'' eggs are unknown. Its eggshell is unornamented and very thin, measuring only 0.44 mm thick. The shell consists of a 0.18 mm mammillary layer (the innermost layer of the shell), a 0.18 mm continuous layer, and a 0.08 mm external layer. The pores are narrow, straight, and constant width throughout the shell. Parentage Because no embryos are known, the parent of ''Plagioolithus'' cannot be identified with certainty. It was formerly believed that triple-layered eggshells were unique to neognath birds, but some three-layered eggs have been found containing enant ...
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Kitadani Formation
The Kitadani Formation ( ja, 北谷層 ''Kitadani-sō'') is a unit of Lower Cretaceous sedimentary rock which crops out near the city of Katsuyama in Fukui Prefecture, Japan, and it is the primary source of Cretaceous-aged non-marine vertebrate fossils in Japan. Dinosaur remains are among the fossils that have been recovered from the formation, but it also preserves a diverse assemblage of plants, invertebrates, and other vertebrates.Weishampel, D.B.; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, D.B.; Dodson, P.; and Osmólska, H. (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. . Most, if not all, of the fossil specimens collected from the Kitadani Formation are reposited at the Fukui Prefectural Dinosaur Museum. The Kitadani Formation is a unit within the Tetori Group, a major sequence of Lower Cretaceous rocks that is distributed across Fukui, Ishikawa, and Gifu prefectures of western-central Honshu. The T ...
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Oogenus
Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of the once- developing embryo inside, in which case it also contains body fossils. A wide variety of different animal groups laid eggs that are now preserved in the fossil record beginning in the Paleozoic. Examples include invertebrates like ammonoids as well as vertebrates like fishes, possible amphibians, and reptiles. The latter group includes the many dinosaur eggs that have been recovered from Mesozoic strata. Since the organism responsible for laying any given egg fossil is frequently unknown, scientists classify eggs using a parallel system of taxonomy separate from but modeled after the Linnaean system. This "parataxonomy" is called ''veterovata''. History The first named oospecies was '' Oolithes bathonicae'', a name given provisi ...
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Fossil Egg
Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of the once- developing embryo inside, in which case it also contains body fossils. A wide variety of different animal groups laid eggs that are now preserved in the fossil record beginning in the Paleozoic. Examples include invertebrates like ammonoids as well as vertebrates like fishes, possible amphibians, and reptiles. The latter group includes the many dinosaur eggs that have been recovered from Mesozoic strata. Since the organism responsible for laying any given egg fossil is frequently unknown, scientists classify eggs using a parallel system of taxonomy separate from but modeled after the Linnaean system. This "parataxonomy" is called ''veterovata''. History The first named oospecies was '' Oolithes bathonicae'', a name given provisi ...
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Egg Fossils
Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of the once- developing embryo inside, in which case it also contains body fossils. A wide variety of different animal groups laid eggs that are now preserved in the fossil record beginning in the Paleozoic. Examples include invertebrates like ammonoids as well as vertebrates like fishes, possible amphibians, and reptiles. The latter group includes the many dinosaur eggs that have been recovered from Mesozoic strata. Since the organism responsible for laying any given egg fossil is frequently unknown, scientists classify eggs using a parallel system of taxonomy separate from but modeled after the Linnaean system. This "parataxonomy" is called ''veterovata''. History The first named oospecies was '' Oolithes bathonicae'', a name given provisi ...
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Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded by the Hauterivian and followed by the Aptian Stage.See Gradstein ''et al.'' (2004) or the online geowhen database (link below) Stratigraphic definitions The original type locality for the Barremian Stage is in the vicinity of the village of Barrême, Alpes-de-Haute-Provence, France. Henri Coquand defined the stage and named it in 1873. The base of the Barremian is determined by the first appearance of the ammonites ''Spitidiscus hugii'' and ''Spitidiscus vandeckii''. The end of the Barremian is determined by the geomagnetic reversal at the start of the M0r chronozone, which is biologically near the first appearance of the ammonite '' Paradeshayesites oglanlensis''. Regional equivalents The Barremian falls in the Gallic epoch, a su ...
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Koshisaurus
''Koshisaurus'' is a monospecific genus of basal hadrosauroid from the Kitadani Formation in Japan. The discovery of the genus suggests that hadrosauroids had higher diversity along the eastern margin of Asia in the Early Cretaceous. "Koshi" means an old Japanese regional name including Fukui prefecture where fossils of the genus were discovered. Description ''Koshisaurus'' was unlike most hadrosauroids due to the fact that it possessed an antorbital fossa, as well as three subsidiary ridges on its maxillary teeth, similar to those of '' Equijubus''. These ridges are also present on the also Asian genera '' Xuwulong'', ''Jinzhousaurus'' and '' Altirhinus''; but all three lack antorbital fossae, placing them as more advanced than ''Koshisaurus''., See also * Timeline of hadrosaur research A timeline is a display of a list of events in chronological order. It is typically a graphic design showing a long bar labelled with dates paralleling it, and usually contemporane ...
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Fukuiraptor
''Fukuiraptor'' ("thief of Fukui") was a medium-sized megaraptoran theropod dinosaur of the Early Cretaceous epoch (either Barremian or Aptian) that lived in what is now Japan. ''Fukuiraptor'' is known from the Kitadani Formation and possibly also the Sebayashi Formation. Description and history The type specimen is a partial skeleton (designated FPDM-V97122) discovered in the Kitadani quarry near Katsuyama in the Fukui prefecture. It is thought that this specimen was not mature and an adult may have been larger. The remains of many other individuals have been found in the quarry, with numerous humeri, femurs, and teeth being assigned to this species. However, the other individuals recovered from the same locality are mostly juveniles that were smaller than the holotype (Currie & Azuma, 2006), in the smallest case less than a quarter of the holotype's size. A tooth (NDC-P0001) discovered in a block of conglomerate from the Sebayashi Formation has been referred to ''F ...
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Fukuisaurus
''Fukuisaurus'' (meaning "Fukui lizard") is a genus of herbivorous ornithopod dinosaur that lived during the Early Cretaceous in what is now Japan. The type species is ''F. tetoriensis'', which was named and described in 2003. Discovery and naming Remains of ''Fukuisaurus'' were discovered in 1989, in Katsuyama, Fukui Prefecture, in rocks from the Kitadani Formation, dating to the Barremian. The type species, ''Fukuisaurus tetoriensis'', was described in 2003 by Yoshitsugu Kobayashi and Yoichi Azuma. The genus name refers to Fukui; the specific name to the geological Tetori Group. The type specimens or cotypes are FPDM-V-40-1, a right maxilla, and FPDM-V-40-2, a right jugal. Further elements of a skull and a right sternal plate had been recovered.Kobayashi, Y. and Azuma, Y. (2003). "A new iguanodontian (Dinosauria; Ornithopoda), form the lower Cretaceous Kitadani Formation of Fukui Prefecture, Japan". ''Journal of Vertebrate Paleontology'' 23(1): 166-175 Since 2003 much more ex ...
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Fukuititan
''Fukuititan'' (meaning "Fukui giant") is a genus of titanosauriform sauropod dinosaur that lived in the Early Cretaceous (either Barremian or Aptian age) in what is now Japan. It is known from FPDM-V8468, the associated partial skeleton of a single individual, recovered from the Kitadani Dinosaur Quarry (Kitadani Formation) of the Tetori Group, at Katsuyama City. The type species, ''Fukuititan nipponensis'', was described in 2010 by Japanese scientists Yoichi Azuma and Masateru Shibata of the Fukui Prefectural Dinosaur Museum The , located in Katsuyama, Fukui, Japan, is one of the leading dinosaur museums in Asia that is renowned for its exhibits of fossil specimens of dinosaurs and paleontological research. It is sited in the Nagaoyama Park ( Katsuyama Dinosaur For .... The discovery sheds light on Japanese titanosauriforms, which are poorly known in the region. References Early Cretaceous dinosaurs of Asia Fossil taxa described in 2010 Macronarians Fossils of ...
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Amiiform
Fish locomotion is the various types of animal locomotion used by fish, principally by swimming. This is achieved in different groups of fish by a variety of mechanisms of propulsion, most often by wave-like lateral flexions of the fish's body and tail in water, and in various specialised fish by motions of the fins. The major forms of locomotion in fish are: * Anguilliform, in which a wave passes evenly along a long slender body; * Sub-carangiform, in which the wave increases quickly in amplitude towards the tail; * Carangiform, in which the wave is concentrated near the tail, which oscillates rapidly; * Thunniform, rapid swimming with a large powerful crescent-shaped tail; and * Ostraciiform, with almost no oscillation except of the tail fin. More specialized fish include movement by pectoral fins with a mainly stiff body, opposed sculling with dorsal and anal fins, as in the sunfish; and movement by propagating a wave along the long fins with a motionless body, as in the knif ...
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Goniopholidid
Goniopholididae is an extinct family of moderate-sized semi-aquatic neosuchian crocodyliformes. Their bodyplan and morphology are convergent on living crocodilians. They lived across Laurasia (Asia, Europe and North America) between the Middle Jurassic (possibly Early Jurassic, see below) and the Late Cretaceous. Description Compared to modern crocodilians, goniopholidids are very unusual in several respects. They possessed two rows of rectangular, interlocking osteoderms like those of terrestrial crocodilymorphs like atoposaurids, that are relatively simple, do not extend far in their necks, as opposed to the ornate armours of modern crocodilians; likewise, unlike modern crocodilians but like many extinct forms like phytosaurs, they have ventral osteoderms as well. Their forelimbs are also proportionally very long, particularly in the humeri and wrist bones, being as long or longer than the hindlimbs, the opposite of the condition seen in modern crocodilians. Some like ''Anteoph ...
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Cryptodira
The Cryptodira ('' el, hidden neck'') are a suborder of Testudines that includes most living tortoises and turtles. Cryptodira differ from Pleurodira (side-necked turtles) in that they lower their necks and pull the heads straight back into the shells, instead of folding their necks sideways along the body under the shells' marginals. They include among their species freshwater turtles, snapping turtles, tortoises, softshell turtles, and sea turtles. Neck retraction The Cryptodira are characterized by retraction of the head in the vertical plane, which permits for primarily vertical movements and restricted lateral movements outside of the shell. These motions are largely due to the morphology and arrangement of cervical vertebrae. In all recent turtles, the cervical column consists of nine joints and eight vertebrae. Compared to the narrow vertebrae and the closely positioned zygapophyses of the pleurodires, the cryptodires’ vertebrae take on the opposite shape. Their ce ...
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