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Allodelphinidae
Allodelphinidae is a family of primitive platanistoid river dolphins found in marine deposits in the eastern North Pacific region, Alaska, and Japan. Description Kimura and Barnes (2016, pp. 3–4) diagnose the family as follows: Systematics ''Allodelphis'' and ''Zarhinocetus'' were formerly classified as members of Delphinidae and Squalodontidae in the original descriptions. In his overview of eastern North Pacific marine mammal assemblages, Lawrence Barnes noted that these two genera did not belong in those families and reassigned ''Allodelphis'' to Platanistidae, while removing ''Squalodon errabundus'' from ''Squalodon ''Squalodon'' is an extinct genus of whales of the Oligocene and Miocene epochs, belonging to the family Squalodontidae. Named by Jean-Pierre Sylvestre de Grateloup in 1840, it was originally believed to be an iguanodontid dinosaur but has sinc ...''. Barnes later realized that ''Allodelphis'' was more primitive than extinct members of Platanistid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arktocara
''Arktocara'' is an extinct genus of river dolphin from the Oligocene epoch of Alaska, containing one species, ''A. yakataga''. Having been discovered in 25-million-year-old strata near the 60th parallel north, it is perhaps the oldest-known crown toothed whale and the northmost river dolphin discovered. It was a member of the now-extinct family Allodelphinidae, along with the genera ''Allodelphis'', '' Goedertius'', '' Ninjadelphis'', and '' Zarhinocetus''. It measured approximately , comparable to its closest living relative, the South Asian river dolphin, which measures . However, the animal probably had an elongated beak and neck, so it may have been longer. The animal is known only from a partially preserved skull. Its ecology may have been similar to the modern-day Dall's porpoise, and it may have competed with contemporaneous delphinoids. Its remains were found in the Poul Creek Formation, which has also yielded several mollusk species. Taxonomy The type specimen, the on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allodelphis
''Allodelphis'' is an extinct genus of whale belonging to Allodelphinidae found in marine deposits of the eastern North Pacific. Description ''Allodelphis'' has a very elongated rostrum and a polydont, heterodont dentition. It differs from '' Ninjadelphis'' and '' Zarhinocetus'' in the following characters: wider dorsal opening of mesorostral canal anterior to dorsal nares, posterior part of rostrum anterior to dorsal nares not depressed, posterior ends of premaxillae less irregular and digitated, posterior ends of premaxillae extending posteriorly beyond level of posterior margins of corresponding nasal bones, nasal bones elevated anteriorly rather than tilting anteroventrally into posterior part of dorsal nares, nasal bones expanded in width anteriorly rather than narrow anteriorly, nasal bones not fused to each other at midline or to underlying frontal bones, instead having margins defined clearly by sutures, nasal bones and dorsal exposures of frontal bones at cranial vert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zarhinocetus
''Zarhinocetus'' is an extinct genus of whale from the Early to Middle Miocene of the eastern North Pacific. Description ''Zarhinocetus'' is a member of Allodelphinidae, a family of primitive dolphins related to the South Asian river dolphin, measuring in length. The rostrum is narrow and elongated, and the teeth are both polydont and heterodont. ''Zarhinocetus'' is distinguished from other allodelphinids in having a depressed medial part of dorsal surface of proximal part of rostrum, enlarged tubercle present on dorsolateral surface of maxilla anterior to antorbital notch, supraorbital process of frontal thicker dorsoventrally, anteroposteriorly-oriented crest present on dorsal surface of supraorbital process of maxilla, bony orbit of larger diameter, dorsal exposures of frontals on cranial vertex asymmetrical with midline suture located to left of cranial midline, zygomatic process of squamosal nearly rectangular in lateral view rather than arc shaped, nuchal crest curving ante ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platanistoidea
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 dolp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goedertius
''Goedertius'' is an extinct genus of river dolphin from the early Miocene (Burdigalian) Nye Formation The Nye Formation is a geologic formation in Oregon. It preserves fossils dating back to the Neogene period. See also * List of fossiliferous stratigraphic units in Oregon * Paleontology in Oregon The location of the state of Oregon Paleont ... of Oregon. Description ''Goedertius'' is distinguished from other allodelphinids by a depression on the posterior part of the rostrum, smaller nasal bones, wider dorsal opening of mesorostral canal on posterior part of rostrum, and dorsal exposures of frontals at cranial vertex smaller.Toshiyuki Kimura and Lawrence G. Barnes (2016). "New Miocene fossil Allodelphinidae (Cetacea, Odontoceti, Platanistoidea) from the North Pacific Ocean". Bulletin of the Gunma Museum of Natural History 20: 1–58. References Fossil taxa described in 2016 Miocene cetaceans Extinct mammals of North America River dolphins {{paleo-whal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ninjadelphis
''Ninjadelphis'' is an extinct genus of river dolphin from the early Miocene (Burdigalian) of Japan. The generic name refers to the fact that the type locality, Iga Iga may refer to: Arts and entertainment * Ambush at Iga Pass, a 1958 Japanese film * Iga no Kagemaru, Japanese manga series * Iga, a set of characters from the Japanese novel '' The Kouga Ninja Scrolls'' Biology * ''Iga'' (beetle), a gen ..., was a training center in Japan for ninja warriors. Description ''Ninjadelphis'' is distinguished from other allodelphinids by having a trapezoidal shaped exposure of frontals on cranial vertex, a nuchal crest partly overhanging posterior end of maxilla, a wider basioccipital, and basioccipital crests widely diverging posteriorly .Toshiyuki Kimura and Lawrence G. Barnes (2016). New Miocene fossil Allodelphinidae (Cetacea, Odontoceti, Platanistoidea) from the North Pacific Ocean. ''Bulletin of the Gunma Museum of Natural History'' 20: 1–58. References Fossil ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platanistidae
Platanistidae is a family of river dolphins containing the extant Ganges river dolphin and Indus river dolphin (both in the genus '' Platanista'') but also extinct relatives from marine deposits in the Neogene. The Amazon river dolphin, Yangtze river dolphin, and franciscana The La Plata dolphin, franciscana or toninha (''Pontoporia blainvillei'') is a species of dolphin found in coastal Atlantic waters of southeastern South America. It is a member of the river dolphin group and the only one that lives in the ocean ... were once thought to belong to Platanistidae (e.g. Simpson, 1945), but cladistic and DNA studies beginning in the 1990s showed that the former three taxa are more closely related to Delphinoidea than to the South Asian river dolphin. The extinct odontocete families Allodelphinidae and Squalodelphinidae are closely related to Platanistidae. Fossils from this clade have been found in deposits in North and South America, Europe, and Central Asia. References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rupelian
The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/Series. It spans the time between . It is preceded by the Priabonian Stage (part of the Eocene) and is followed by the Chattian Stage. Name The stage is named after the small river Rupel in Belgium, a tributary to the Scheldt. The Belgian Rupel Group derives its name from the same source. The name Rupelian was introduced in scientific literature by Belgian geologist André Hubert Dumont in 1850. The separation between the group and the stage was made in the second half of the 20th century, when stratigraphers saw the need to distinguish between lithostratigraphic and chronostratigraphic names. Stratigraphic definition The base of the Rupelian Stage (which is also the base of the Oligocene Series) is at the extinction of the foraminiferan genus ''Hantkenina''. An official GSSP for the base of the Rupelian has been assigned in 1992 (Massignano, Italy). The transitio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Langhian
The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene Epoch/Series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma (million years ago) during the Middle Miocene.GeoWhen (2007) The Langhian was a continuing warming period defined by Lorenzo Pareto in 1865, it was originally established in the Langhe area north of Ceva in northern Italy, hence the name. The Langhian is preceded by the Burdigalian and followed by the Serravallian Stage. Stratigraphic definition The base of the Langhian is defined by the first appearance of foraminifer species ''Praeorbulina glomerosa'' and is also coeval with the top of magnetic chronozone C5Cn.1n. A GSSP for the Langhian Stage was not yet established in 2009. The top of the Langhian Stage (the base of the Serravallian Stage) is at the first occurrence of fossils of the nanoplankton species ''Sphenolithus heteromorphus'' and is located in magnetic chronozone C5ABr. The Langhian is coeval with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squalodon
''Squalodon'' is an extinct genus of whales of the Oligocene and Miocene epochs, belonging to the family Squalodontidae. Named by Jean-Pierre Sylvestre de Grateloup in 1840, it was originally believed to be an iguanodontid dinosaur but has since been reclassified. The name ''Squalodon'' comes from ''Squalus'', a genus of shark. As a result, its name means "shark tooth". Its closest modern relative is the South Asian river dolphin (with its two subspecies the Ganges river dolphin and Indus river dolphin). Description Species of ''Squalodon'' are odontocetes that lived during the late Oligocene into the middle Miocene, about 28 to 15 million years ago. The genus ''Squalodon'' belongs to the order Odontoceti, the toothed whales. They are named after the shark ''Squalus'' because their cheek teeth look like the teeth of a squalus shark. The largest species, ''Squalodon whitmorei'', reached up to 5.5 meters in length. The unique-looking squalodontids were likely distributed throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squalodelphinidae
Squalodelphinidae is a family of primitive platanistoid river dolphins found in marine deposits in the eastern Pacific, western Atlantic, and Europe. Description Distinguishing features of Squalodelphinidae include a moderately elongated and tapered rostrum, posterior cheek teeth being single-rooted but retaining accessory denticles, and marked skull asymmetry. Members of the family can be differentiated from the South Asian river dolphin South Asian river dolphins are toothed whales in the genus ''Platanista'', which inhabit fresh water habitats in the northern Indian subcontinent. They were historically considered to be one species (''P. gangetica'') with the Ganges river dol ... by their shorter rostrum.O. Lambert, G. Bianucci, and M. Urbina. 2014. Huaridelphis raimondii, a new early Miocene Squalodelphinidae (Cetacea, Odontoceti) from the Chilcatay Formation, Peru. Journal of Vertebrate Paleontology 34(5):987-1004 References {{Taxonbar, from=Q21291935 Prehistoric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Toothed Whales
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] |
