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Eolambia
''Eolambia'' (meaning "dawn lambeosaurine") is a genus of herbivorous hadrosauroid dinosaur from the early Late Cretaceous of the United States. It contains a single species, ''E. caroljonesa'', named by paleontologist James Kirkland in 1998. The type specimen of ''Eolambia'' was discovered by Carole and Ramal Jones in 1993; the species name honors Carole. Since then, hundreds of bones have been discovered from both adults and juveniles, representing nearly every element of the skeleton. All of the specimens have thus far been found in Emery County, Utah, in a layer of rock known as the Mussentuchit Member of the Cedar Mountain Formation. Measuring up to long, ''Eolambia'' is a large member of its group. While it closely approaches the Asian hadrosauroids ''Equijubus'', ''Probactrosaurus'', and ''Choyrodon'', in traits of the skull, vertebrae, and limbs, it may actually be more closely related to the North American ''Protohadros''. This grouping, based on the straightness of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadrosauroidea
Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to ''Iguanodon''. Their remains have been recovered in Asia, Europe, Africa and the Americas. Many primitive hadrosauroids, such as the Asian ''Probactrosaurus'' and ''Altirhinus'', have traditionally been included in a paraphyly, paraphyletic (unnatural grouping) "Iguanodontidae". With cladistics, cladistic analysis, the traditional Iguanodontidae has been largely disbanded, and probably includes only ''Iguanodon'' and perhaps its closest relatives. Classification The cladogram below follows an analysis by Andrew McDonald, 2012, and shows the position of Hadrosauroidea within Styracosterna. The cladogram below follows an analysis by Wu Wenhao and Pascal Godefroit (2012). Cladogram after Prieto-Marquez and Norell (2010). A phylogenetic analysis performed by Ramírez-Velasco ''et al.'' (2012) foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Choyrodon
''Choyrodon'' (meaning "Choir tooth" after where it was first discovered) is a genus of hadrosauroid dinosaur from the Early Cretaceous Albian-age Khuren Dukh Formation of Mongolia. The type and only species is ''Choyrodon barsboldi''. The generic name is derived from the city of Choyr, and ''-odon'', from Greek for tooth; the specific name ''barsboldi'' honours paleontologist Rinchen Barsbold. The material consists of a holotype partial skull and cervical ribs, with two other partial skulls both with associated postcranial material. It was found to be the sister taxon of ''Eolambia''. Three specimens are known: MPC-D 100/801 (the holotype), MPC-D 100/800 and MPC-D 100/803. See also * 2018 in paleontology * 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 contemporaneous events. Timelines can use any suitable scale repre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cedar Mountain Formation
The Cedar Mountain Formation is the name given to a distinctive sedimentary geologic formation in eastern Utah, spanning most of the early and mid-Cretaceous. The formation was named for Cedar Mountain (Utah), Cedar Mountain in northern Emery County, Utah, where William Lee Stokes first studied the exposures in 1944. Geology The formation occurs between the underlying Morrison Formation and overlying Naturita Formation (sometimes formerly called the Dakota Formation). It is composed of non-marine sediments, that is, sediments deposited in rivers, lakes and on flood plains. Based on various fossils and radiometric dating, radiometric dates, the Cedar Mountain Formation was deposited during the last half of the Early Cretaceous Epoch, about 127 - 98 million years ago (mya). It has lithography similar to the Burro Canyon Formation in the region. Dinosaur fossils occur throughout the formation, but their study has only occurred since the early 1990s. The dinosaurs in the lower part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Kirkland (paleontologist)
James Ian Kirkland (born August 24, 1954) is an American paleontologist and geologist. He has worked with dinosaur remains from the south west United States of America and Mexico and has been responsible for discovering new and important genera. He named (or worked with others in naming) ''Animantarx'', '' Cedarpelta'', '' Eohadrosaurus'' ('' nomen nudum'', now named ''Eolambia''), '' Jeyawati'', '' Gastonia'', ''Mymoorapelta'', '' Nedcolbertia'', ''Utahraptor'', ''Zuniceratops'', ''Europelta'' and ''Diabloceratops''. At the same site where he found '' Gastonia'' and ''Utahraptor'', Kirkland has also excavated fossils of the therizinosaur ''Falcarius''.Kirkland, Zanno, Sampson, Clark & DeBlieux 2005, pp. 84-87. Career Born August 24, 1954, Weymouth, Massachusetts. High School, Marshfield High School, Marshfield, Massachusetts. 1972 B.S. Geological Sciences, New Mexico Institute of Mining and Technology, Socorro, New Mexico. 1977 (Pres. Student Body, 1975-1976) M.S. Geology, Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1998 In Paleontology
Flora Lycophytes Lycophyte research *Wehr (1998) reports, without description, ''Selaginella'' species spikemoss fossils occurring in the Eocene Okanagan highlands Klondike Mountain Formation. Fungi Fungal research *Currah, Stockey, & LePage (1998) describe the a phyllachoralean " tar spot" parasitizing ''Uhlia'' palm leaves, and host for a hyperparasitic pleosporalean fungus. They note them to be one of the first occurrences of hyperparasitic relationships in the fossil record. Arthropods Insects Molluscs Bivalves Amphibians newly named anurans Archosauromorpha Dinosaurs * A paper in the journal ''Nature'' is published by Karen Chin and others announcing the earlier discovery of a "king-sized coprolite" attributed to ''Tyrannosaurus rex''. * ''Lourinhasaurus'' gastroliths documented.Dantas et al. (1998). Sanders, Manley, and Carpenter (2001), "Table 12.1" page 167. * ''Cedarosaurus'' gastroliths documented.Sanders and Carpenter (1998). Sanders, Manley, and Car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Precession
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis. In the absence of precession, the astronomical body's orbit would show axial parallelism. In particular, axial precession can refer to the gradual shift in the orientation of Earth's axis of rotation in a cycle of approximately 26,000 years.Hohenkerk, C.Y., Yallop, B.D., Smith, C.A., & Sinclair, A.T. "Celestial Reference Systems" in Seidelmann, P.K. (ed.) ''Explanatory Supplement to the Astronomical Almanac''. Sausalito: University Science Books. p. 99. This is similar to the precession of a spinning top, with the axis tracing out a pair of cones joined at their apices. The term "precession" typically refers only to this largest part of the motion; other changes in the alignment of Earth's axis—nutation and polar motion—are much smaller in magnitude. Earth's precession was historically called the precession of the equinoxes, because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodylomorpha
Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. During Mesozoic and early Cenozoic times, crocodylomorphs were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. The earliest and most primitive crocodylomorphs are represented by " sphenosuchians", a paraphyletic assemblage containing small-bodied forms with elongated limbs that walked upright, which represents the ancestral morphology of Crocodylomorpha. These forms persisted until the end of the Jurassic. During the Jurassic, Crocodylomorphs morphologically diversified into numerous niches, including into the aquatic and marine realms. Evolutionary history When their extinct species and stem group are examined, the crocodylian lineage (clade Pseudosuchia, formerly Crurotarsi) proves to have been a very diverse and adaptive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flowering Plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (). Like gymnosperms, angiosperms are seed-producing plants. They are distinguished from gymnosperms by characteristics including flowers, endosperm within their seeds, and the production of fruits that contain the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. The closest fossil relatives of flowering plants are uncertain and contentious. The earliest angiosperm fossils ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fern
A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except the lycopods, and differ from mosses and other bryophytes by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaves called megaphylls, that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae) and eusporangiate ferns, the latter group including horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns. Ferns first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrate Bone
The quadrate bone is a skull bone in most tetrapods, including amphibians, sauropsids (reptiles, birds), and early synapsids. In most tetrapods, the quadrate bone connects to the quadratojugal and squamosal bones in the skull, and forms upper part of the jaw joint. The lower jaw articulates at the articular bone, located at the rear end of the lower jaw. The quadrate bone forms the lower jaw articulation in all classes except mammals. Evolutionarily, it is derived from the hindmost part of the primitive cartilaginous upper jaw. Function in reptiles In certain extinct reptiles, the variation and stability of the morphology of the quadrate bone has helped paleontologists in the species-level taxonomy and identification of mosasaur squamates and spinosaurine dinosaurs. In some lizards and dinosaurs, the quadrate is articulated at both ends and movable. In snakes, the quadrate bone has become elongated and very mobile, and contributes greatly to their ability to swallow very ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudie, A. S., 2004, ''Encyclopedia of Geomorphology'', vol. 1. Routledge, New York. The soils usually consist of clays, silts, sands, and gravels deposited during floods. Because the regular flooding of floodplains can deposit nutrients and water, floodplains frequently have high soil fertility; some important agricultural regions, such as the Mississippi river basin and the Nile, rely heavily on the flood plains. Agricultural regions as well as urban areas have developed near or on floodplains to take advantage of the rich soil and fresh water. However, the risk of flooding has led to increasing efforts to control flooding. Formation Most floodplains are formed by deposition on the inside of river meanders and by overbank flow. Whereve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Convergence
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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