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Arriagadoolithus
''Arriagadoolithus'' is the oogenus of fossil eggs which includes the eggs of the alvarezsaurid '' Bonapartenykus''. Fossils of the creature were found in Patagonia; it may have brooded on its eggs. Description ''Arriagadoolithus patagoniensis'' is known from two partial eggs both found associated with a skeleton of ''Bonapartenykus ultimus''. The eggs are about in maximum width, but the length of the eggs and whether or not they were symmetric are unknown. Unlike most non-avian dinosaur eggs,Laura E. Wilson, Karen Chin, Frankie D. Jackson, and Emily S. BrayII. Eggshell morphology and structure ''UCMP Online Exhibits: Fossil Eggshell'' ''Arriagadoolithus'' shell has three layers (external, prismatic, and mammillary). The shell is approximately thick. The outer surface of its eggshell is covered with two distinct ornamentation patterns: the unique dendro-reticulate ornament, made up of randomly interconnecting ridges with nodes along the ridges or where they intersect; and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arriagadoolithidae
Arriagadoolithidae is an oofamily of fossil eggs, representing the eggs of Alvarezsaurs. Description The eggs are well stratified with three layers: the external, the prismatic, and the mammillary. The connection between prismatic and external layers is abrupt. The eggshell is similar to that of birds, and has ornamentation similar to that of Elongatoolithids. History Previously, Arriagadoolithid eggs were considered to be Elongatoolithids, because the similarities in shell ornamentation. However, they have quite distinct eggshell structure, which was recognized by Jackson and Varricchio (2010) when they named a new oogenus, '' Triprismatoolithus''. The oofamily was first described in 2012, following the discovery of fossil eggs associated with the Alvarezsaur, ''Bonapartenykus''; Agnolin ''et al'' erected a new oogenus, ''Arriagadoolithus ''Arriagadoolithus'' is the oogenus of fossil eggs which includes the eggs of the alvarezsaurid ''Bonapartenykus''. Fossils of the creature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triprismatoolithus
''Triprismatoolithus'' is an oogenus of dinosaur egg native to Teton County, Montana. It is classified in the oofamily Arriagadoolithidae, the eggs of alvarezsaurs. Distribution ''Triprismatoolithus'' is known exclusively from Sevenmile Hill, a fossil site at the Two Medicine Formation in Teton County, Montana. It is the oldest known fossil egg site at that formation, dating to 80 million years ago, the early part of the Campanian. History Fossil eggs are common from the upper part of the Two Medicine formation, but it was not until 2010 that paleontologists discovered eggs in the lower part, including ''Triprismatoolithus''. They were discovered by two paleontologists from the University of Montana: Frankie D. Jackson and David J. Varricchio. It remained of uncertain classification (because no similar eggs were known) until 2012 when Agnolin '' et al.'' discovered similar eggs associated with ''Bonapartenykus'', which they classified with ''Triprismatoolithus'' in a new oofamily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bonapartenykus
''Bonapartenykus'' (meaning " José F. Bonaparte's claw") is a monospecific genus of alvarezsauroid dinosaur from Argentina that lived during the Late Cretaceous (Campanian-Maastrichtian) in what is now the upper Allen Formation of the Río Negro Province. The type and only species, ''Bonapartenykus ultimus'', is known from a nearly articulated but partial skeleton that was found in close association to two incomplete eggs and several clusters of eggshells belonging to the oogenus ''Arriagadoolithus''. ''Bonapartenykus'' was named in 2012 by Federico L. Agnolin, Jaime E. Powell, Fernando E. Novas and Martin Kundrát. ''Bonapartenykus'' has an estimated length of and weight of , making it the largest member of the clade Alvarezsauroidea. Discovery and Naming A partial skeleton of a theropod with eggs was collected in a surface of approximately 30 m2 in fluvial sandstones of the upper Allen Formation in northwestern Patagonia, Argentina. The locality has also produced specimen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bonapartenykus Ultimus
''Bonapartenykus'' (meaning "José F. Bonaparte's claw") is a monospecific genus of alvarezsauroid dinosaur from Argentina that lived during the Late Cretaceous (Campanian-Maastrichtian) in what is now the upper Allen Formation of the Río Negro Province. The type and only species, ''Bonapartenykus ultimus'', is known from a nearly articulated but partial skeleton that was found in close association to two incomplete eggs and several clusters of eggshells belonging to the oogenus ''Arriagadoolithus''. ''Bonapartenykus'' was named in 2012 by Federico L. Agnolin, Jaime E. Powell, Fernando E. Novas and Martin Kundrát. ''Bonapartenykus'' has an estimated length of and weight of , making it the largest member of the clade Alvarezsauroidea. Discovery and Naming A partial skeleton of a theropod with eggs was collected in a surface of approximately 30 m2 in fluvial sandstones of the upper Allen Formation in northwestern Patagonia, Argentina. The locality has also produced specimens o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 provis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur Reproduction
Dinosaur reproduction was relevant to archosaur physiology, with newborns hatching from eggs. Dinosaurs did not nurture their offspring as mammals typically do, and because dinosaurs did not nurse, it is likely that most dinosaurs were capable of surviving on their own after hatching. Medullary bone A discovery of features in a ''Tyrannosaurus rex'' skeleton provided more evidence that dinosaurs and birds evolved from a common ancestor and, for the first time, allowed paleontologists to establish the sex of a dinosaur. When laying eggs, female birds grow a special type of bone between the hard outer bone and the marrow of their limbs. This ''medullary'' bone, which is rich in calcium, is used to make eggshells. The presence of endosteally derived bone tissues lining the interior marrow cavities of portions of the ''Tyrannosaurus rex'' specimen's hind limb suggested that ''T. rex'' used similar reproductive strategies, and revealed the specimen to be female. Further research has fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Parataxa Described In 2012
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from . The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene). The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event) occurred at the end of this age. In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about wide colliding with Earth, ending the Cretaceous. Stratigraphic definitions Definition The Maastrichtian was introduced into scientific literature by Belgian geologist André Hubert Dumont in 1849, after studying rock strata of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.Gradstein ''et al.'' (2004) Stratigraphic definition The Santonian Stage was established by French geologist Henri Coquand in 1857. It is named after the city of Saintes in the region of Saintonge, where the original type locality is located. The base of the Santonian Stage is defined by the appearance of the inoceramid bivalve '' Cladoceramus undulatoplicatus''. The GSSP (official reference profile) for the base of the Santonian Stage is located near Olazagutia, Spain; it was ratified by the Subcommission on Cretaceous Stratigraphy in 2012. The Santonian's top (the base of the Campanian Stage) is informally marked by the extinction of the crinoid '' Marsup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
