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Eomysticetus
''Eomysticetus'' is an extinct genus of baleen whale from the late Oligocene (Chattian) Chandler Bridge Formation of South Carolina. (148Mb) Taxonomy ''Eomysticetus'' is a member of the family Eomysticetidae, which also includes '' Micromysticetus'', '' Tohoraata'', '' Tokarahia'', and '' Yamatocetus''. There are two species of ''Eomysticetus'', ''E. whitmorei'' and ''E. carolinensis'', both from the Chandler Bridge Formation of South Carolina. Physical characteristics The skull was around in length. Like more evolved baleen whales, its jaws had baleen instead of teeth, meaning that it could filter plankton with its baleen plates. However, primitive baleen whales may have retained enamel coated teeth embedded in the gums, similar to modern sperm whales. Baleen whales, as a group, may be sensitive to low-frequency sounds. Unlike modern baleen whales, ''Eomysticetus'' had a blowhole that was positioned ahead of the eyes, and the characteristics of its vertebrae and flipper bon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eomysticetidae
Eomysticetidae is a family of extinct mysticetes belonging to Chaeomysticeti (toothless mysticetes). It is one of two families in the basal chaeomysticete clade Eomysticetoidea (the other being Cetotheriopsidae). Description Eomysticetids are united by the following combination of primitive and derived characters relative to more advanced chaeomysticetes (Balaenomorpha): zygomatic process without a supramastoid crest; reduction of the superior process of the periotic into a low ridge with anterior and posterior apices in medial or lateral view; blowholes situated ahead of the eyes; an elongated intertemporal region with long parietal and frontal exposures on the cranial vertex; elongated nasals; large coronoid processes of the mandibles; flat rostrum; laterally bowed mandibles; absence of functional teeth; and large mandibular foramina. Taxonomy There are seven genera of Eomysticetidae: ''Eomysticetus'', ''Matapanui'', ''Micromysticetus'', ''Tohoraata'', ''Tokarahia'', ''Wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baleen Whales
Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae (right and bowhead whales), Balaenopteridae (rorquals and the gray whale), and Cetotheriidae (the pygmy right whale). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychids, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago. Baleen whales range in size from the and pygmy right whale to the and blue whale, the largest known animal to have ever existed. They are sexually dimorphic. Baleen whales can have streamlined or large bodies, depending on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baleen Whale
Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae (right and bowhead whales), Balaenopteridae (rorquals and the gray whale), and Cetotheriidae (the pygmy right whale). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychids, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago. Baleen whales range in size from the and pygmy right whale to the and blue whale, the largest known animal to have ever existed. They are sexually dimorphic. Baleen whales can have streamlined or large bodies, depending on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tohoraata
''Tohoraata'' is a genus of eomysticetid baleen whale from the Late Oligocene (Chattian) of New Zealand. There are two recognized species, ''T. raekohao'' and ''T. waitakiensis''.Robert W. Boessenecker and R. Ewan Fordyce (2014). "A new Eomysticetid (Mammalia: Cetacea) from the Late Oligocene of New Zealand and a re-evaluation of ‘Mauicetus’ waitakiensis". Papers in Palaeontology. in press. doi:10.1002/spp2.1005. Classification ''Tohoraata'' is a member of the family Eomysticetidae, a family of primitive baleen-bearing mysticetes (chaeomysticetes). The type species, ''T. raekohao'', is based on OU 22178, a partial skull associated with a thoracic vertebra and five ribs, collected from the Maerewhenua Member of the Otekaike Limestone. On the other hand, ''T. waitakiensis'', is known from OMC GL 402, a partial skull and five neck vertebrae collected in the Kokoamu Greensand. It was originally described as a species of ''Mauicetus'', but was eventually recognized as more primi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yamatocetus
''Yamatocetus canaliculatus'' is an extinct species of eomysticetid baleen whale from the Late Oligocene of Japan. Taxonomy The holotype specimen, a partial skeleton, was discovered by curator Toshiyuki Kamei in October 1981 in the Ashiya Group of the Jinnobaru Formation on the island of Kyushu, and stored in the Kitakyushu Museum of Natural History and Human History. The genus name honors the old name of Japan, Yamato, and Latin ''cetus'', "whale." The species name translates to "with groove" in reference to the grooves in its mouth which indicate functional baleen. It was placed into the family Eomysticetidae, a primitive group of baleen whales. Description As in other baleen whales, the skull is wide and flat. The skull, along the sides, has several narrow, straight grooves–eight in total–and there are several foramina in the skull used as passage for blood vesselsthough not as many as modern baleen whales–which indicate it had baleen in its mouth. The skull cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chandler Bridge Formation
The Chandler Bridge Formation is a geologic formation in South Carolina. It preserves fossils dating back to the Chattian (Late Oligocene) of the Paleogene period, corresponding to the Arikareean in the NALMA classification.Chandler Bridge Formation at .org The formation overlies the and is overlain by the Edisto Formation. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Enamel
Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The other major tissues are dentin, cementum, and Pulp (tooth), dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. Calcium hardens the tooth enamel. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Mammals Of North America
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. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene Cetaceans
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basilosaurus
''Basilosaurus'' (meaning "king lizard") is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). First described in 1834, it was the first archaeocete and prehistoric whale known to science. Fossils attributed to the type species ''B. cetoides'' were discovered in the United States. They were originally thought to be of a giant reptile, hence the suffix "-saurus", Ancient Greek for "lizard". The animal was later found to be an early marine mammal, which prompted attempts at renaming the creature, which failed as the rules of zoological nomenclature dictate using the original name given. Fossils were later found of the second species, ''B. isis'', in 1904 in Egypt, Western Sahara, Morocco, Jordan, Tunisia, and Pakistan. Fossils have also been unearthed in the southeastern United States and Peru. ''Basilosaurus'' is considered to have been common in the Tethys Ocean. It was one of the largest, if not t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeocetes
Archaeoceti ("ancient whales"), or Zeuglodontes in older literature, is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene (). Representing the earliest cetacean radiation, they include the initial amphibious stages in cetacean evolution, thus are the ancestors of both modern cetacean suborders, Mysticeti and Odontoceti. This initial diversification occurred in the shallow waters that separated India and Asia , resulting in some 30 species adapted to a fully oceanic life. Echolocation and filter-feeding evolved during a second radiation . All archaeocetes from the Ypresian (56–47.8 mya) and most from the Lutetian (47.8–41.3 mya) are known exclusively from Indo-Pakistan, but Bartonian (41.3–38.0 mya) and Priabonian (38.0–33.9 mya) genera are known from across Earth, including North America, Egypt, New Zealand, and Europe. Although no consensus exists regarding the mode of locomotion of which cetaceans were capable during the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sperm Whale Family
Physeteroidea is a superfamily that includes three extant species of whales: the sperm whale, in the genus ''Physeter'', and the pygmy sperm whale and dwarf sperm whale, in the genus ''Kogia''. In the past, these genera have sometimes been united in a single family, the Physeteridae, with the two ''Kogia'' species in the subfamily Kogiinae; however, recent practice is to allocate the genus ''Kogia'' to its own family, the Kogiidae, leaving the Physeteridae as a monotypic (single extant species) family, although additional fossil representatives of both families are known. Characteristics The sperm whale (''Physeter macrocephalus'') is the largest species of toothed whale, with adult bulls (males) growing to be about long, and weighing about . The two kogiid species are much smaller, around in length, and weighing . The bodies of physeteroids are robustly proportioned, with paddle-shaped flippers. The lower jaw is always relatively small and thin relative to the upper jaw. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
