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Pygmy Right Whale
The pygmy right whale (''Caperea marginata'') is a species of baleen whale. It may be a member of the cetotheres, a family of baleen whales which until 2012 were thought to be extinct; ''C. marginata'' has otherwise been considered the monotypic taxon sole member of the family Neobalaenidae and is the only member of the genus ''Caperea''. First described by John Edward Gray in 1846, it is the smallest of the baleen whales, ranging between in length and in mass. Despite its name, the pygmy right whale may have more in common with the gray whale and rorquals than the bowhead and right whales. The pygmy right whale is found in temperate waters of the Southern Hemisphere, and feeds on copepods and euphausiids. Little is known about its population or social habits. Unlike most other baleen whales, it has rarely been subject to exploitation. Taxonomy During the 1839-43 voyage of James Clark Ross, naturalists found bones and baleen plates resembling a smaller version of the rig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Pleistocene
The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The Chibanian name was officially ratified in January 2020. It is currently estimated to span the time between 0.770 Ma (770,000 years ago) and 0.126 Ma (126,000 years ago), also expressed as 770–126 ka. It includes the transition in palaeoanthropology from the Lower to the Middle Palaeolithic over 300 ka. The Chibanian is preceded by the Calabrian and succeeded by the proposed Tarantian. The beginning of the Chibanian is the Brunhes–Matuyama reversal, when the Earth's magnetic field last underwent reversal. It ends with the onset of the Eemian interglacial period (Marine Isotope Stage 5). The term Middle Pleistocene was in use as a provisional or "quasi-formal" designation by the International Union of Geological Sciences (IUGS). W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Living Fossil
A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are of species-poor lineages, but they need not be. While the body plan of a living fossil remains superficially similar, it is never the same species as the remote relatives it resembles, because genetic drift would inevitably change its chromosomal structure. Living fossils exhibit stasis (also called "bradytely") over geologically long time scales. Popular literature may wrongly claim that a "living fossil" has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological changes. Scientific investigations have repeatedly discredited such claims. The minimal superficial changes to living fossils are mistakenly declared as an absence of evolution, but they are examples of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sei Whale
The sei whale ( , ; ''Balaenoptera borealis'') is a baleen whale, the third-largest rorqual after the blue whale and the fin whale. It inhabits most oceans and adjoining seas, and prefers deep offshore waters. It avoids polar and tropical waters and semi-enclosed bodies of water. The sei whale migrates annually from cool, subpolar waters in summer to temperate, subtropical waters in winter with a lifespan of 70 years. Reaching in length and weighing as much as , the sei whale consumes an average of of food every day; its diet consists primarily of copepods, krill, and other zooplankton. It is among the fastest of all cetaceans, and can reach speeds of up to (27 knots) over short distances. The whale's name comes from the Norwegian word for pollock, a fish that appears off the coast of Norway at the same time of the year as the sei whale. Following large-scale commercial whaling during the late 19th and 20th centuries, when over 255,000 whales were killed, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minke Whale
The minke whale (), or lesser rorqual, is a species complex of baleen whale. The two species of minke whale are the common (or northern) minke whale and the Antarctic (or southern) minke whale. The minke whale was first described by the Danish naturalist Otto Fabricius in 1780, who assumed it must be an already known species and assigned his specimen to ''Balaena rostrata'', a name given to the northern bottlenose whale by Otto Friedrich Müller in 1776. In 1804, Bernard Germain de Lacépède described a juvenile specimen of ''Balaenoptera acuto-rostrata''. The name is a partial translation of Norwegian ''minkehval'', possibly after a Norwegian whaler named Meincke, who mistook a northern minke whale for a blue whale. Taxonomy Most modern classifications split the minke whale into two species; * Common minke whale or northern minke whale (''Balaenoptera acutorostrata'') :and *Antarctic minke whale or southern minke whale (''Balaenoptera bonaerensis''). Taxonomists further categ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-finned Pilot Whale
The long-finned pilot whale (''Globicephala melas'') is a large species of oceanic dolphin. It shares the genus '' Globicephala'' with the short-finned pilot whale (''Globicephala macrorhynchus''). Long-finned pilot whales are known as such because of their unusually long pectoral fins. Taxonomy and naming Etymology Pilot whales get their name from the original belief that there was a "pilot" or lead individual in their groups.Olson, P.A. (2008). "Pilot whale ''Globicephala melas'' and ''G. muerorhynchus''". pp. 847–52 in ''Encyclopedia of Marine Mammals''. Perrin, W. F., Wursig, B., and Thewissen, J. G. M. (eds.). Academic Press; 2nd edition. Ridgway, S. H. (1998). ''Handbook of Marine Mammals: The second book of dolphins and the porpoises''. Volume 6, Elsevier. pp. 245–69. The name for the genus, "''Globicephala''" is derived from a combination of Latin ''globus'' ("globe") and Greek ''kephale'' ("head"). The specific name "''melas''" is Greek for "black". This species h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laryngeal Pouch
The laryngeal ventricle, (also called the ventricle of the larynx, laryngeal sinus, or Morgagni's sinus) in lexic.us. Updated 05 Mar 2000 is a fossa, situated between the and s on either side, and extending nearly their entire length. There is also a [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrous Part Of The Temporal Bone
The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior, the components of the inner ear. The petrous portion is among the most basal elements of the skull and forms part of the endocranium. Petrous comes from the Latin word ''petrosus'', meaning "stone-like, hard". It is one of the densest bones in the body. The petrous bone is important for studies of ancient DNA from skeletal remains, as it tends to contain extremely well-preserved DNA. Base The base is fused with the internal surfaces of the squamous and mastoid parts. Apex The apex, which is rough and uneven, is received into the angular interval between the posterior border of the great wing of the sphenoid bone and the basilar part of the occipital bone; it presents the anterior or internal openin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supraoccipital Shield
The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cerebrum. At the base of skull in the occipital bone, there is a large oval opening called the foramen magnum, which allows the passage of the spinal cord. Like the other cranial bones, it is classed as a flat bone. Due to its many attachments and features, the occipital bone is described in terms of separate parts. From its front to the back is the basilar part, also called the basioccipital, at the sides of the foramen magnum are the lateral parts, also called the exoccipitals, and the back is named as the squamous part. The basilar part is a thick, somewhat quadrilateral piece in front of the foramen magnum and directed towards the pharynx. The squamous part is the curved, expanded plate behind the foramen magnum and is the largest part o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Fin
A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through convergent evolution they have independently evolved external superficial fish-like body plans adapted to their marine environments, including most numerously fish, but also mammals such as cetaceans (whales, dolphins, and porpoises), and even extinct ancient marine reptiles such as various known species of ichthyosaurs. Most species have only one dorsal fin, but some have two or three. Wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of large cetaceans to identify individuals in the field. The bony or cartilaginous bones that support the base of the dorsal fin in fish are called ''pterygiophores''. Functions The main purpose of the dorsal fin is to stabilize the animal against rollin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Callosity
A callosity is another name for callus, a piece of skin that has become thickened as a result of repeated contact and friction. Primates All Old World monkeys, gibbons, and some chimpanzees have pads on their rears known as ischial callosities. Ischial relates to the ischium: it forms the lower and back part of the hip bone. The pads enable the monkeys to sleep sitting upright on thin branches, beyond reach of predators, without falling. The ischial callosities are one of the most distinctive pelvic features which separates Old World monkeys from New World monkeys. Right whales In whales, the term ''callosity'' refers to the rough, calcified skin patches found on the heads of the three species of right whales. These callosities are a characteristic feature of the whale genus ''Eubalaena''; because they are found on the head of the whale and appear white against the dark background of the whale's skin, they make it very easy to identify these species. The callosities th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Minke Whale
The Antarctic minke whale or southern minke whale (''Balaenoptera bonaerensis'') is a species of minke whale within the suborder of baleen whales. It is the second smallest rorqual after the common minke whale and the third smallest baleen whale. Although first scientifically described in the mid-19th century, it was not recognized as a distinct species until the 1990s. Once ignored by the whaling industry due to its small size and low oil yield, the Antarctic minke was able to avoid the fate of other baleen whales and maintained a large population into the 21st century, numbering in the hundreds of thousands.Branch, T. A. (2006). "Abundance estimates for Antarctic minke whales from three completed circumpolar sets of surveys, 1978/79 to 2003/04". ''Paper'' SC/58/IA18 ''submitted to the International Whaling Commission Scientific Committee'', pp. 1–28. Surviving to become the most abundant baleen whale in the world, it is now one of the mainstays of the industry alongside its c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Minke Whale
The common minke whale or northern minke whale (''Balaenoptera acutorostrata'') is a species of minke whale within the suborder of baleen whales. It is the smallest species of the rorquals and the second smallest species of baleen whale. Although first ignored by whalers due to its small size and low oil yield, it began to be exploited by various countries beginning in the early 20th century. As other species declined larger numbers of common minke whales were caught, largely for their meat. It is now one of the primary targets of the whaling industry. There is a dwarf form in the Southern Hemisphere. This species is known in the fossil record from the Pliocene epoch to the Quaternary period (age range: 3.6 million years ago to present day). Vernacular names The origins of the species' common name are obscure. One of the first references to the name came in Henrik Johan Bull's account of his 1893–95 voyage to the Antarctic, when he mentioned catching a small whale "called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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