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Leidyosuchus
''Leidyosuchus'' (meaning " Leidy's crocodile") is an extinct genus of alligatoroid from the Late Cretaceous of Alberta. It was named in 1907 by Lawrence Lambe, and the type species is ''L. canadensis''. It is known from a number of specimens from the middle Campanian age Dinosaur Park Formation. It was a medium-sized alligatorid, with a maximum skull length greater than 40 centimeters (16 in). A number of species had been assigned to this genus over the years, including: ''L. acutidentatus'' ( Sternberg, 1932), from the Paleocene of Saskatchewan; ''L. formidabilis'' ( Erickson, 1976), from the Paleocene of North Dakota and Wyoming; ''L. gilmorei'' (Mook, 1942), from the Campanian of Alberta; ''L. multidentatus'' (Mook, 1930); ''L. riggsi'' (Schmidt, 1938); ''L. sternbergii'' (Gilmore, 1910), from the Maastrichtian (Late Cretaceous) of Colorado, Montana, North Dakota, South Dakota, and Wyoming; and ''L. wilsoni'' (Mook, 1959), from the Eocene of Wyoming. However, in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borealosuchus
''Borealosuchus'' (meaning "boreal crocodile") is an extinct genus of crocodyliforms that lived from the Late Cretaceous to the Eocene in North America. It was named by Chris Brochu in 1997 for several species that had been assigned to ''Leidyosuchus''. The species assigned to it are: ''B. sternbergii'', the type species, from the Maastrichtian (Late Cretaceous) of Colorado, Montana, North Dakota, South Dakota, and Wyoming; ''B. acutidentatus'', from the Paleocene of Saskatchewan; ''B. formidabilis'', from the Paleocene of North Dakota; ''B. griffithi'', from the Paleocene of Alberta; and ''B. wilsoni'', from the Eocene of Wyoming. ''B. formidabilis'' is particularly well-known, represented by the remains of many individuals from the Wannagan Creek site in North Dakota. ''Borealosuchus'' was a mid-sized crocodyliform; ''B. acutidentatus'' reached up to in length with a skull. Taxonomy Six species of ''Borealosuchus'' are currently recognized. In order of their naming, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Listrognathosuchus
''Listrognathosuchus'' is an extinct genus of alligatoroid crocodilian. Fossils date back to the middle Paleocene epoch. In 1997, the generic name replaced that of ''Leidyosuchus'' for the species ''L. multidentatus'' (now the type species of ''Listrognathosuchus''). ''"L." multidentalis'' was first described by Charles Mook in 1930 on the basis of the holotype AMNH 5179, consisting of a partial vertebral column, mandible, partial left ilium, and left tibia, found from a locality in Torrejon Arroyo, New Mexico (then referred to as the Torrejon beds, and now thought to be part of the Nacimiento Formation). Phylogenetics The fragmentary nature of the material referable to ''Listrognathosuchus'' have made it hard to classify within Crocodylia, but it is now thought to be a relatively basal alligatoroid. ''Listrognathosuchus'' is closely related to '' Borealosuchus'', a more basal eusuchian that is not an alligatoroid, but rather a close relative of a monophyletic group of which the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alligatoroidea
Alligatoroidea is one of three superfamilies of crocodylians, the other two being Crocodyloidea and Gavialoidea. Alligatoroidea evolved in the Late Cretaceous period, and consists of the alligators and caimans, as well as extinct members more closely related to the alligators than the two other groups. Evolution The superfamily Alligatoroidea is thought to have split from the crocodile-gharial lineage in the late Cretaceous, about 80 million years ago, but possibly as early as 100 million years ago based on molecular phylogenetics. '' Leidyosuchus'' of Alberta is the earliest known genus. Fossil alligatoroids have been found throughout Eurasia as land bridges across both the North Atlantic and the Bering Strait have connected North America to Eurasia during the Cretaceous, Paleogene, and Neogene periods. Alligators and caimans split in North America during the early Tertiary or late Cretaceous (about 53 million to about 65 million years ago) and the latter reached Sout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur Park Formation
The Dinosaur Park Formation is the uppermost member of the Belly River Group (also known as the Judith River Group), a major geologic unit in southern Alberta. It was deposited during the Campanian stage of the Late Cretaceous, between about 76.5 and 74.4 million years ago. It was deposited in alluvial and coastal plain environments, and it is bounded by the nonmarine Oldman Formation below it and the marine Bearpaw Formation above it.Eberth, D.A. 2005. The geology. In: Currie, P.J., and Koppelhus, E.B. (eds), Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Indiana University Press: Bloomington and Indianapolis, p.54-82. . The Dinosaur Park Formation contains dense concentrations of dinosaur skeletons, both articulated and disarticulated, which are often found with preserved remains of soft tissues. Remains of other animals such as fish, turtles, and crocodilians, as well as plant remains, are also abundant. The formation has been named after Dinos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Lambe
Lawrence Morris Lambe (August 27, 1863 – March 12, 1919) was a Canadian geologist, palaeontologist, and ecologist from the Geological Survey of Canada (GSC). His published work, describing the diverse and plentiful dinosaur discoveries from the fossil beds in Alberta, did much to bring dinosaurs into the public eye and helped usher in the ''Golden Age of Dinosaurs'' in the province. During this period, between the 1880s and World War I, dinosaur hunters from all over the world converged on Alberta. ''Lambeosaurus'', a well-known hadrosaur, was named after him as a tribute, in 1923. In addition to paleontology, Lambe discovered a number of invertebrate species ranging from Canada to the Pacific Northwest. Lambe's contemporary discoveries were published in works such as ''Sponges From the Atlantic Coast of Canada'' and ''Catalogue of the recent marine sponges of Canada and Alaska''. Early life and education Lambe was born in Montreal on August 27, 1863. Lambe studied at the Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montana
Montana () is a U.S. state, state in the Mountain states, Mountain West List of regions of the United States#Census Bureau-designated regions and divisions, division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Provinces and territories of Canada, Canadian provinces of Alberta, British Columbia, and Saskatchewan to the north. It is the List of U.S. states and territories by area, fourth-largest state by area, the List of U.S. states and territories by population, eighth-least populous state, and the List of U.S. states and territories by population density, third-least densely populated state. Its state capital is Helena, Montana, Helena. The western half of Montana contains numerous mountain ranges, while the eastern half is characterized by western prairie terrain and badlands, with smaller mountain ranges found throughout the state. Montana has no official nickname but several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Dakota
South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota people, Dakota Sioux Native Americans in the United States, Native American tribes, who comprise a large portion of the population with nine Indian reservation, reservations currently in the state and have historically dominated the territory. South Dakota is the List of U.S. states and territories by area, seventeenth largest by area, but the List of U.S. states and territories by population, 5th least populous, and the List of U.S. states and territories by population density, 5th least densely populated of the List of U.S. states, 50 United States. As the southern part of the former Dakota Territory, South Dakota became a state on November 2, 1889, simultaneously with North Dakota. They are the 39th and 40th states admitted to the union; Pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and e ... [...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] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and diversification. However, such a correlation does not make a given case predicable, so ancestral characters should not be imputed ... [...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] |
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