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Macrorhizodus Nolfi
''Macrorhizodus'' is an extinct genus of Mackerel shark which lived during the early to middle Eocene epoch of the Paleogene period. It is often considered ancestral to ''Isurus'' and sometimes considered part of it. ''Macrorhizodus'' is also likely ancestral to ''Cosmopolitodus''. It seems to be related to ''Isurolamna''. It is known from isolated teeth and vertebral centra as well as at least two associated dentitions. It is an incredibly widespread shark, known from every continent except Australia. This includes a report from Antarctica. Species The genus is composed of the following species: This genus appears to have undergone anagenesis Anagenesis is the gradual evolution of a species that continues to exist as an interbreeding population. This contrasts with cladogenesis, which occurs when there is branching or splitting, leading to two or more lineages and resulting in separate ..., making it difficult to draw lines between species. Some authors prefer to lump and oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrorhizodus Falcatus
''Macrorhizodus'' is an extinct genus of Mackerel shark which lived during the early to middle Eocene epoch of the Paleogene period. It is often considered ancestral to ''Isurus'' and sometimes considered part of it. ''Macrorhizodus'' is also likely ancestral to ''Cosmopolitodus''. It seems to be related to ''Isurolamna''. It is known from isolated teeth and vertebral centra as well as at least two associated dentitions. It is an incredibly widespread shark, known from every continent except Australia. This includes a report from Antarctica. Species The genus is composed of the following species: This genus appears to have undergone anagenesis Anagenesis is the gradual evolution of a species that continues to exist as an interbreeding population. This contrasts with cladogenesis, which occurs when there is branching or splitting, leading to two or more lineages and resulting in separate ..., making it difficult to draw lines between species. Some authors prefer to lump and oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrorhizodus Americana
''Macrorhizodus'' is an extinct genus of Mackerel shark which lived during the early to middle Eocene epoch of the Paleogene period. It is often considered ancestral to ''Isurus'' and sometimes considered part of it. ''Macrorhizodus'' is also likely ancestral to ''Cosmopolitodus''. It seems to be related to ''Isurolamna''. It is known from isolated teeth and vertebral centra as well as at least two associated dentitions. It is an incredibly widespread shark, known from every continent except Australia. This includes a report from Antarctica. Species The genus is composed of the following species: This genus appears to have undergone anagenesis, making it difficult to draw lines between species. Some authors prefer to lump and others to split. The early Oligocene species ''Macrorhizodus flandricus'' ascribed to this genus now usually considered to be a synonym of ''Isurus desori'', sometimes styled ''Isurus desori flandrica''. However, ''I. desori'' might itself be a junior synon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrorhizodus Praecursor
''Macrorhizodus'' is an extinct genus of Mackerel shark which lived during the early to middle Eocene epoch of the Paleogene period. It is often considered ancestral to ''Isurus'' and sometimes considered part of it. ''Macrorhizodus'' is also likely ancestral to ''Cosmopolitodus''. It seems to be related to ''Isurolamna''. It is known from isolated teeth and vertebral centra as well as at least two associated dentitions. It is an incredibly widespread shark, known from every continent except Australia. This includes a report from Antarctica. Species The genus is composed of the following species: This genus appears to have undergone anagenesis Anagenesis is the gradual evolution of a species that continues to exist as an interbreeding population. This contrasts with cladogenesis, which occurs when there is branching or splitting, leading to two or more lineages and resulting in separate ..., making it difficult to draw lines between species. Some authors prefer to lump and oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrorhizodus Nolfi
''Macrorhizodus'' is an extinct genus of Mackerel shark which lived during the early to middle Eocene epoch of the Paleogene period. It is often considered ancestral to ''Isurus'' and sometimes considered part of it. ''Macrorhizodus'' is also likely ancestral to ''Cosmopolitodus''. It seems to be related to ''Isurolamna''. It is known from isolated teeth and vertebral centra as well as at least two associated dentitions. It is an incredibly widespread shark, known from every continent except Australia. This includes a report from Antarctica. Species The genus is composed of the following species: This genus appears to have undergone anagenesis Anagenesis is the gradual evolution of a species that continues to exist as an interbreeding population. This contrasts with cladogenesis, which occurs when there is branching or splitting, leading to two or more lineages and resulting in separate ..., making it difficult to draw lines between species. Some authors prefer to lump and oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the lower Eocene. Events The Ypresian Age begins during the throes of the Paleocene–Eocene Thermal Maximum (PETM). The Fur Formation in Denmark, the Messel shales in Germany, the Oise amber of France and Cambay amber of India are of this age. The Eocene Okanagan Highlands are an uplands subtropical to temperate series of lakes from the Ypresian. Stratigraphic definition The Ypresian Stage was introduced in scientific literature by Belgian geologist André Hubert Dumont in 1850. The Ypresian is named after the Flemish city of Ypres in Belgium (spelled ''Ieper'' in Dutch). The definitions of the original stage were totally different from the modern ones. The Ypresian shares its name with the Belgian Ieper Grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santee Limestone
The Santee Limestone is a geologic formation in South Carolina. It preserves fossils dating back to the Paleogene period. See also * List of fossiliferous stratigraphic units in South Carolina This article contains a list of fossil-bearing stratigraphic units in the state of South Carolina, U.S. Sites See also * Paleontology in South Carolina References * {{DEFAULTSORT:Fossiliferous stratigraphic units in South Carolina Sou ... * Paleontology in South Carolina References * Limestone formations of the United States Paleogene geology of South Carolina {{SouthCarolina-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamnidae
The Lamnidae are the family of mackerel sharks known as white sharks. They are large, fast-swimming predatory fish found in oceans worldwide, though prefer environments with colder water. The name of the family is formed from the Greek word ''lamna'', which means "fish of prey", and was derived from the Greek legendary creature, the Lamia.: ''A source-book of biological names and terms'', 1944, Edmund Carroll Jaeger These sharks have pointed snouts, spindle-shaped bodies, and large gill openings. The first dorsal fin is large, high, stiff and angular or somewhat rounded. The second dorsal and anal fins are minute. The caudal peduncle has a couple of less distinct keels. The teeth are gigantic. The fifth gill opening is in front of the pectoral fin and spiracles are sometimes absent. They are powerful, heavily built sharks, sometimes weighing nearly twice as much as other sharks of comparable length from other families. Many sharks in the family are among the fastest-swimmin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortfin Mako Shark
The shortfin mako shark (; ; ''Isurus oxyrinchus''), also known as the blue pointer or bonito shark, is a large mackerel shark. It is commonly referred to as the mako shark, as is the longfin mako shark (''Isurus paucus''). The shortfin mako can reach a size of in length and weigh . The species is classified as Endangered by the IUCN. Etymology "Mako" comes from the Māori language, meaning either the shark or a shark tooth. Following the Māori language, "mako" in English is both singular and plural. The word may have originated in a dialectal variation, as it is similar to the common words for shark in a number of Polynesian languages—''makō'' in the Kāi Tahu Māori dialect, ''mangō'' in other Māori dialects, "mago" in Samoan, ''ma'o'' in Tahitian, and ''mano'' in Hawaiian. The first written usage is in Lee and Kendall's ''Grammar and vocabulary of the language of New Zealand'' (1820), which simply states, "Máko; A certain fish". Richard Taylor's ''A leaf fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anagenesis
Anagenesis is the gradual evolution of a species that continues to exist as an interbreeding population. This contrasts with cladogenesis, which occurs when there is branching or splitting, leading to two or more lineages and resulting in separate species. Anagenesis does not always lead to the formation of a new species from an ancestral species. When speciation does occur as different lineages branch off and cease to interbreed, a core group may continue to be defined as the original species. The evolution of this group, without extinction or species selection, is anagenesis. Hypotheses One hypothesis is that during the speciation event in anagenetic evolution, the original populations will increase quickly, and then rack up genetic variation over long periods of time by mutation and recombination in a stable environment. Other factors such as selection or genetic drift will have such a significant effect on genetic material and physical traits that a species can be ackno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dakhla, Western Sahara
Dakhla ( ar, الداخلة, Berber: Eddaxla / ⴷⴷⴰⵅⵍⴰ, es, Dajla, Villa Cisneros) is a city in the disputed territory of Western Sahara, currently occupied by Morocco. It is the capital of the claimed Moroccan administrative region Dakhla-Oued Ed-Dahab. It has a population of 106,277 and is on a narrow peninsula of the Atlantic Coast, the Río de Oro Peninsula, about south of Laayoune. History The area has been inhabited by Berbers since ancient times. Oulad Dlim is an Arab tribe of Himyari from Yemen that settled in the Sahara in the twelfth century. Dakhla was expanded by Spanish settlers during the expansion of their empire. The Spanish interest in the desert coast of Western Africa's Sahara arose as the result of fishing carried out from the nearby Canary Islands by Spanish fishers and as a result of the Barbary pirates menace. Spanish fishers were seal fur traders and hunters, fishers and whalers along the Saharan coast from Dakhla to Cabo Blanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Priabonian
The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene Epoch or Series. It spans the time between . The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage of the Oligocene. Stratigraphic definition The Priabonian Stage was introduced in scientific literature by Ernest Munier-Chalmas and Albert de Lapparent in 1893. The stage is named after the small hamlet of Priabona in the community of Monte di Malo, in the Veneto region of northern Italy. The base of the Priabonian Stage is at the first appearance of calcareous nannoplankton species ''Chiasmolithus oamaruensis'' (which forms the base of nanoplankton biozone NP18). An official GSSP was ratified in 2020, and was placed in the Alano di Piave section in Alano di Piave, Belluno, Italy. The top of the Priabonian Stage (the base of the Rupelian Stage and Oligocene Series) is at the extinction of foram genus ''Hantkenina''. Sometime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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