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Auroracetus
''Auroracetus'', from ''Aurora'' (the location the holotype was discovered, Aurora N.C.) and the Latin ''cetus'' (whale), is a genus of Pontoporiidae, the river dolphins, and contains one extinct species. The species ''Auroracetus bakerae'' was published in 2009. Taxonomic history Holotype specimen The original specimen of ''A. bakerae'' was donated to the Smithsonian by Aura Baker, aided by Wayne Baker. The specimen consists of a fragmentary skull from a juvenile individual. The nasal passages (the nose or "blowhole") as well as the back of the skull were preserved, however the rostrum and basicranium were not. Classification as a new genus and species was based on the odd shape of its nasal bones, the lack of any ridge along the edges of the skull as seen in other river dolphins, and the width of the sutures, or spaces, between facial bones. The specimen was collected from the Lee Creek Mine in Aurora, North Carolina. The skull was reconstructed by Matthew Gibson, and formall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Dolphins
River dolphins are a polyphyletic group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which itself is a paraphyletic group within the infraorder Cetacea. Extant river dolphins are placed in two superfamilies, Platanistoidea and Inioidea. They comprise the families Platanistidae (the South Asian dolphins), the recently extinct Lipotidae (Yangtze river dolphin), Iniidae (the Amazonian dolphins) and Pontoporiidae. There are five extant species of river dolphins. River dolphins, alongside other cetaceans, belong to the clade Artiodactyla, with even-toed ungulates, and their closest living relatives the hippopotamuses, from which they diverged about 40 million years ago. Specific types of Dolphins can be pink. River dolphins are relatively small compared to other dolphins, having evolved to survive in warm, shallow water and strong river currents. They range in size from the long South Asian river dol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Dolphin
River dolphins are a polyphyletic group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which itself is a paraphyletic group within the infraorder Cetacea. Extant river dolphins are placed in two superfamilies, Platanistoidea and Inioidea. They comprise the families Platanistidae (the South Asian dolphins), the recently extinct Lipotidae (Yangtze river dolphin), Iniidae (the Amazonian dolphins) and Pontoporiidae. There are five extant species of river dolphins. River dolphins, alongside other cetaceans, belong to the clade Artiodactyla, with even-toed ungulates, and their closest living relatives the hippopotamuses, from which they diverged about 40 million years ago. Specific types of Dolphins can be pink. River dolphins are relatively small compared to other dolphins, having evolved to survive in warm, shallow water and strong river currents. They range in size from the long South Asian river ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Extinct Cetaceans
The list of extinct cetaceans features the extinct genera and species of the order Cetacea. The cetaceans ( whales, dolphins and porpoises) are descendants of land-living mammals, the even-toed ungulates. The earliest cetaceans were still hoofed mammals. These early cetaceans became gradually better adapted for swimming than for walking on land, finally evolving into fully marine cetaceans. This list currently includes only fossil genera and species. However, the Atlantic population of gray whales (''Eschrichtius robustus'') became extinct in the 18th century, and the baiji (or Chinese river dolphin, ''Lipotes vexillifer'') was declared " functionally extinct" after an expedition in late 2006 failed to find any in the Yangtze River. Suborder Archaeoceti Family Ambulocetidae (Eocene) * '' Ambulocetus'' * '' Himalayacetus'' * ''Gandakasia'' Family Basilosauridae (Late Eocene) * Basilosaurinae ** '' Basilosaurus'' ** '' Basiloterus'' ** '' Eocetus'' ** '' Platyosphys'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58See the 2014 version of the ICS geologic time scale million years ago. It is the second and most recent epoch of the Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georgia Southern University
Georgia Southern University (GS or Georgia Southern) is a public research university in the U.S. state of Georgia. The flagship campus is in Statesboro, and other locations include the Armstrong Campus in Savannah and the Liberty Campus in Hinesville. Founded back in 1906 as a land grant college, Georgia Southern is the fifth largest institution in the University System of Georgia and is the largest center of higher education within the southern half of Georgia. The institution offers over 140 different academic majors in a comprehensive array of baccalaureate, masters, and doctoral programs. The university has a combined enrollment of approximately 27,000 students from all 50 states and approximately 85 nations. Georgia Southern is classified among "R2: Doctoral Universities – High research activity" and a comprehensive university by the University System of Georgia. On the Statesboro Campus is the Center for Wildlife Education and the Lamar Q Ball Jr. Raptor Center, an edu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly '' Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the Museum of Comparative Zoology at Harvard University. In botany, an isotype is a duplicate of the holotype, where holotype and isotypes are often pieces from the same individual plant or samples from the same gathering. A holotype is not necessaril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution Of Cetaceans
The evolution of cetaceans is thought to have begun in the Indian subcontinent from even-toed ungulates 50 million years ago (mya) and to have proceeded over a period of at least 15 million years. Cetaceans are fully aquatic marine mammals belonging to the order Artiodactyla and branched off from other artiodactyls around 50 mya. Cetaceans are thought to have evolved during the Eocene (56-34 mya), the second epoch of the present-extending Cenozoic Era. Molecular and morphological analyses suggest Cetacea share a relatively recent closest common ancestor with hippopotami and that they are sister groups. Being mammals, they surface to breathe air; they have 5 finger bones (even-toed) in their fins; they nurse their young; and, despite their fully aquatic life style, they retain many skeletal features from their terrestrial ancestors.Thewissen, J. G. M., L. N. Cooper, J. C. George, and S. Bajpai. 2009. From land to water: the origin of whales, dolphins, and porpoises. Evol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Cetaceans
Cetacea is an infraorder that comprises the 94 species of whales, dolphins, and porpoises. It is divided into toothed whales (Odontoceti) and baleen whales (Mysticeti), which diverged from each other in the Eocene some 50 mya (unit), million years ago (mya). Cetaceans are descended from land-dwelling hoofed mammals, and the now extinct archaeocetes represent the several transitional phases from terrestrial to completely aquatic. Historically, cetaceans were thought to have descended from the wolf-like mesonychids, but cladistic analyses confirm their placement with even-toed ungulates in the order Cetartiodactyla. Whale populations were drastically reduced in the 20th century from intensive whaling, and the activity was globally banned in 1982. Smaller cetaceans are at risk of accidentally getting caught by fishing vessels using, namely, seine fishing, drift netting, or gill netting operations. Conventions The following is a list of currently existing (or, in the jargon of ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Monotypic Mammal Genera
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
