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Tiktaalik
''Tiktaalik'' (; ) is a monospecific genus of extinct sarcopterygian (lobe-finned fish) from the Late Devonian Period, about 375 Mya (million years ago), having many features akin to those of tetrapods (four-legged animals). ''Tiktaalik'' is estimated to have had a total length of on the basis of various specimens. Unearthed in Arctic Canada, ''Tiktaalik'' is a non-tetrapod member of Osteichthyes (bony fish), complete with scales and gills—but it has a triangular, flattened head and unusual, cleaver-shaped fins. Its fins have thin ray bones for paddling like most fish, but they also have sturdy interior bones that would have allowed ''Tiktaalik'' to prop itself up in shallow water and use its limbs for support as most four-legged animals do. Those fins and other mixed characteristics mark ''Tiktaalik'' as a crucial Transitional fossil, transition fossil, a link in evolution from swimming fish to four-legged vertebrates. This and similar animals might be the common ancestors of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapod
A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetrapoda (). Tetrapods include all Neontology#Extant taxa versus extinct taxa, extant and Extinction, extinct amphibians and amniotes, with the latter in turn Evolution, evolving into two major clades, the Sauropsida, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (extinct pelycosaur, "pelycosaurs", therapsids and all extant mammals, including Homo sapiens, humans). Hox gene mutations have resulted in some tetrapods becoming Limbless vertebrate, limbless (snakes, legless lizards, and caecilians) or two-limbed (cetaceans, sirenians, Bipedidae, some lizards, kiwi (bird), kiwis, and the extinct moa and elephant birds). Nevertheless, they still qualify as tetrapods through their ancestry, and some retain a pair of ves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transitional Fossil
A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. Therefore, it cannot be assumed that transitional fossils are direct ancestors of more recent groups, though they are frequently used as models for such ancestors. In 1859, when Charles Darwin's ''On the Origin of Species'' was first published, the fossil record was poorly known. Darwin described the perceived lack of transitional fossils as "the most obvious and gravest objection which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neil Shubin
Neil Shubin (born December 22, 1960) is an American paleontologist, evolutionary biologist and popular science writer. He is the Robert R. Bensley Professor of Organismal Biology and Anatomy, Associate Dean of Organismal Biology and Anatomy and Professor on the Committee of Evolutionary Biology at the University of Chicago along with being the Provost of the Field Museum of Natural History. He is best known for his co-discovery of '' Tiktaalik roseae'' with Ted Daeschler and Farish Jenkins. Biography Raised in Overbrook Hills section of Lower Merion Township (contiguous to City of Philadelphia) and a graduate of Lower Merion High School, Shubin earned a A.B. from Columbia College of Columbia University in 1982 and a Ph.D. in organismic and evolutionary biology from Harvard University in 1987. He also studied at the University of California, Berkeley. Shubin was elected to the National Academy of Sciences in 2011. Shubin was ABC News' "Person of the Week" in April 2006 when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fram Formation
The Fram Formation is an Upper Devonian (Frasnian) sequence of rock strata on Ellesmere Island that came into prominence in 2006 with the discovery in its rocks of examples of the transitional fossil, ''Tiktaalik'', a sarcopterygian or lobe-finned fish showing many tetrapod characteristics. Fossils of '' Laccognathus embryi'', a porolepiform lobe-finned fish, and '' Qikiqtania'', a close relative of ''Tiktaalik'', were also found in the formation. The Fram Formation is a Middle to Upper Devonian clastic wedge forming an extensive continental facies consisting of sediments derived from deposits laid down in braided stream systems that formed some 375 million years ago, Fossil pollen suggest that these rocks lie within the early and middle Frasnian Stage of the Devonian. at a time when the North American craton ("Laurentia") was straddling the equator. Paleobiota Vertebrates See also * List of fossiliferous stratigraphic units in Nunavut * Escuminac Formation, another Frasnia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcopterygian
Sarcopterygii (; )—sometimes considered synonymous with Crossopterygii ()—is a clade (traditionally a class or subclass) of vertebrate animals which includes a group of bony fish commonly referred to as lobe-finned fish. These vertebrates are characterised by prominent muscular limb buds (lobes) within their fins, which are supported by articulated appendicular skeletons. This is in contrast to the other clade of bony fish, the Actinopterygii, which have only skin-covered bony spines supporting the fins. The tetrapods, a mostly terrestrial clade of vertebrates, are now recognized as having evolved from sarcopterygian ancestors and are most closely related to lungfishes. Their paired pectoral and pelvic fins evolved into limbs, and their foregut diverticulum eventually evolved into air-breathing lungs. Cladistically, this would make the tetrapods a subgroup within Sarcopterygii and thus sarcopterygians themselves. As a result, the phrase "lobe-finned fish" normally re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farish Jenkins
Farish Alston Jenkins (May 19, 1940 – November 11, 2012) was a professor at Harvard University who studied and taught paleontology. His discoveries included a transitional creature with characteristics of both fish and land animals, '' Tiktaalik roseae,'' and one of the earliest known frogs, ''Prosalirus bitis''. Early life Farish Jenkins was born in Manhattan on May 19, 1940. He was the oldest of three sons of a marketing executive but was raised by his grandmother in Colorado while his father served in World War II. Jenkins studied geology at Princeton, where he met his wife Eleanor Tracy. He served in the United States Marine Corps for four years, where he became a captain. After arriving to Yale in 1964 to continue his studies in geology, Jenkins took a trip to Nairobi where he is said to have taken his first interest in live animal research: "At the time, black rhinos in the bush were as thick as rats in a dump. With my camera set on self-timer, I managed to p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ted Daeschler
Edward B. 'Ted' Daeschler is an American vertebrate paleontologist and Associate Curator and Chair of Vertebrate Biology at the Academy of Natural Sciences in Philadelphia. He is a specialist in fish paleontology, especially in the Late Devonian, and in the development of the first limbed vertebrates. He is the discoverer of the transitional fossil tetrapod '' Hynerpeton bassetti'', and a Devonian fish-like specimen of '' Sauripterus taylori'' with fingerlike appendages, and was also part of a team of researchers that discovered the transitional fossil ''Tiktaalik''. He received a Ph.D. from the University of Pennsylvania in 1998. He has held recent research grants from the National Science Foundation, the National Geographic Society, and other donors. He is also known for his work on the preservation of natural history collections."Endangered collections" by Rex Dalton Nature 446, 605-606 (5 April 2007) He is a professor at Drexel University in the Department of Biodiversity, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2006 In Paleontology
Plants Ferns and fern allies Angiosperms Arthropods Crustaceans Insects Molluscs Cephalopods Tetrapodomorphs Amphibians Newly named temnospondylians Newly named amphibians Ichthyosaurs Lepidosauromorphs Newly named basal lepidosauromorphs Newly named plesiosaurs Newly named squamates Turtles Archosauromorphs Newly named crurotarsans Newly named dinosaurs * Vickaryous, M K., 2006, New information on the cranial anatomy of Edmontonia rugosidens Gilmore, a Late Cretaceous nodosaurid dinosaur from Dinosaur Provincial Park, Alberta: JVP, v. 26, n. 4: 1011–1013. Data are courtesy of George Olshevky's dinosaur genera list. Newly named birds Newly named pterosaurs Synapsids Non-mammalian Mammals Trace fossils * The trace fossil genera ''Nihilichnus'' (''Nihilichnus nihilicus'' and ''Nihilichnus mortalis''), ''Machichnus'' (''Machichnus regularis,'' ''Machichnus multilineatus'', and ''Machichnus bohemicus'') and ''Brutalichnus'' (''Brutalic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellesmere Island
Ellesmere Island (; ) is Canada's northernmost and List of Canadian islands by area, third largest island, and the List of islands by area, tenth largest in the world. It comprises an area of , slightly smaller than Great Britain, and the total length of the island is . Lying within the Arctic Archipelago, Ellesmere Island is considered part of the Queen Elizabeth Islands. Cape Columbia at is the most northerly point of land in Canada and one of the most northern points of land on the planet (the most northerly point of land on Earth is the nearby Kaffeklubben Island of Greenland). The Arctic Cordillera mountain system covers much of Ellesmere Island, making it the most mountainous in the Arctic Archipelago. More than one-fifth of the island is protected as Quttinirpaaq National Park. In 2021, the population of Ellesmere Island was recorded at 144. There are three settlements: Alert, Nunavut, Alert, Eureka, Nunavut, Eureka, and Grise Fiord. Ellesmere Island is administered as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Museum
The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educational and scientific programs, and its extensive scientific specimen and artifact collections. The permanent exhibitions, which attract up to 2 million visitors annually, include fossils, current cultures from around the world, and interactive programming demonstrating today's urgent conservation needs. The museum is named in honor of its first major benefactor, Marshall Field, the department-store magnate. The museum and its collections originated from the 1893 World's Columbian Exposition and the artifacts displayed at the fair. The museum maintains a temporary exhibition program of traveling shows as well as in-house produced topical exhibitions. The professional staff maintains collections of over 24 million specimens and objects ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academy Of Natural Sciences
The Academy of Natural Sciences of Drexel University, formerly the Academy of Natural Sciences of Philadelphia, is the oldest natural science research institution and museum in the Americas. It was founded in 1812, by many of the leading naturalists of the young American republic with an expressed mission of "the encouragement and cultivation of the sciences". It has sponsored expeditions, conducted original environmental and systematics research, and amassed natural history collections containing more than 17 million specimens. The Academy also organizes public exhibits and educational programs for both schools and the general public. History During the first decades of the United States, Philadelphia was the cultural capital and one of the country's commercial centers. Two of the city's institutions, the Library Company and the American Philosophical Society, were centers of enlightened thought and scientific inquiry. The increasing sophistication of the earth and life sci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding Carboniferous period at Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of life on land occurred during the Devonian, as free- sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants ( pteridospermatophytes) appeared. This rapid evolution and colonization process, which had begun during the Silurian, is known as the Silurian-Devonian Terrestrial Rev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
