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Macroraptorial Sperm Whale
Macroraptorial sperm whales were highly predatory whales of the sperm whale superfamily (Physeteroidea) of the Miocene epoch that hunted large marine mammals, including other whales, using their large teeth. They consist of five genera: ''Acrophyseter'', ''Albicetus'', '' Brygmophyseter'', '' Livyatan'', and '' Zygophyseter''. All species are known by at least a skull, and are informally grouped without a family designation. They were all likely the apex predator of their habitats, comparable to the modern day killer whale (''Orcinus orca''), and achieved great lengths, with one species–'' Livyatan''–measuring about . Discovery ''Zygophyseter'' was discovered in the Pietra Leccese Formation in Italy from a skull, teeth, and vertebrae; ''Brygmophyseter'' was discovered in the Bessho Formation in Japan from a nearly-complete skeleton; and ''Acrophyseter'' and ''Livyatan'' both originate from the Pisco Formation in Peru and are known by only a skull. ''Albicetus'' is discovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Livyatan Melvillei Skull
''Livyatan'' is an extinct genus of macroraptorial sperm whale containing one known species: ''L. melvillei''. The genus name was inspired by the biblical sea monster Leviathan, and the species name by Herman Melville, the author of the famous novel ''Moby-Dick'' about a white bull sperm whale. It is mainly known from the Pisco Formation of Peru during the Tortonian stage of the Miocene epoch, about 9.9–8.9 million years ago (mya); however, finds of isolated teeth from other locations such as Chile, Argentina, South Africa, and Australia imply that either it or a close relative survived into the Pliocene, around 5mya, and was present throughout the Southern Hemisphere. It was a member of a group of macroraptorial sperm whales (or "raptorial sperm whales") and was probably an apex predator, preying on whales, seals, and so forth. Characteristically of raptorial sperm whales, ''Livyatan'' had functional, enamel-coated teeth on the upper and lower jaws, as well as several fea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santa Barbara Light
Santa Barbara Lighthouse was a lighthouse in California, United States, on the Santa Barbara Harbor, California. History When Santa Barbara Lighthouse was established on December 1, 1856, it was typical of the other pioneer West Coast lights, with the tower rising through the center of the dwelling. The builder was George D. Nagle of San Francisco who received $8,000 for his efforts. The tower lantern was fitted with a fourth order lens and originally displayed a fixed red light, which in later years was changed to fixed white. * Historical Information by United States Coast Guard: Women lighthouse keepers were not uncommon in early American lighthouses. Santa Barbara is a premier example. When the lighthouse was officially established in 1856, Albert Johnson Williams was appointed as the initial keeper. After nine years of operating the facility he grew tired of his routine chores and handed over the duties to his wife. She proved so adept at keeping a good house that the go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagic Zone
The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the surface of the sea and the bottom. Conditions in the water column change with depth: pressure increases; temperature and light decrease; salinity, oxygen, micronutrients (such as iron, magnesium and calcium) all change. Marine life is affected by bathymetry (underwater topography) such as the seafloor, shoreline, or a submarine seamount, as well as by proximity to the boundary between the ocean and the atmosphere at the ocean surface, which brings light for photosynthesis, predation from above, and wind stirring up waves and setting currents in motion. The pelagic zone refers to the open, free waters away from the shore, where marine life can swim freely in any direction unhindered by topographical constraints. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longissimus Muscle
The longissimus ( la, the longest one) is the muscle lateral to the semispinalis muscles. It is the longest subdivision of the erector spinae muscles that extends forward into the transverse processes of the posterior cervical vertebrae. Structure Longissimus thoracis et lumborum The longissimus thoracis et lumborum is the intermediate and largest of the continuations of the erector spinae. In the lumbar region (longissimus lumborum), where it is as yet blended with the iliocostalis, some of its fibers are attached to the whole length of the posterior surfaces of the transverse processes and the accessory processes of the lumbar vertebrae, and to the anterior layer of the lumbodorsal fascia. In the thoracic region (longissimus thoracis), it is inserted, by rounded tendons, into the tips of the transverse processes of all the thoracic vertebrae, and by fleshy processes into the lower nine or ten ribs between their tubercles and angles. Longissimus cervicis The longissimus cer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multifidus Muscle
The multifidus (multifidus spinae : ''pl. multifidi'' ) muscle consists of a number of fleshy and tendinous fasciculi, which fill up the groove on either side of the spinous processes of the vertebrae, from the sacrum to the axis. While very thin, the multifidus muscle plays an important role in stabilizing the joints within the spine. The multifidus is one of the transversospinales. Located just superficially to the spine itself, the multifidus muscle spans three joint segments and works to stabilize these joints at each level. The stiffness and stability makes each vertebra work more effectively, and reduces the degeneration of the joint structures caused by friction from normal physical activity. These fasciculi arise: * ''in the sacral region:'' from the back of the sacrum, as low as the fourth sacral foramen, from the aponeurosis of origin of the sacrospinalis, from the medial surface of the posterior superior iliac spine, and from the posterior sacroiliac ligaments. * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumbar Vertebra
The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse process (since it is only found in the cervical region) and by the absence of facets on the sides of the body (as found only in the thoracic region). They are designated L1 to L5, starting at the top. The lumbar vertebrae help support the weight of the body, and permit movement. Human anatomy General characteristics The adjacent figure depicts the general characteristics of the first through fourth lumbar vertebrae. The fifth vertebra contains certain peculiarities, which are detailed below. As with other vertebrae, each lumbar vertebra consists of a ''vertebral body'' and a ''vertebral arch''. The vertebral arch, consisting of a pair of ''pedicles'' and a pair of ''laminae'', encloses the ''vertebral foramen'' (opening) and su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buccal Exostoses
A buccal exostosis is an exostosis (bone prominence) on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible. More commonly seen in the maxilla than the mandible, buccal exostoses are considered to be site specific. Existing as asymptomatic bony nodules, buccal exostoses don’t usually present until adult life, and some consider buccal exostoses to be a variation of normal anatomy rather than disease. Bone is thought to become hyperplastic, consisting of mature cortical and trabecular bone with a smooth outer surface. They are less common when compared with mandibular tori. Signs and symptoms Buccal exostoses are bony hamartomas, which are non- malignant, exophytic nodular outgrowths of dense cortical bone that are relatively avascular.’ Symptoms: Buccal exostoses generally tend to be asymptomatic and are usually painless. However, they may increase patient concern about poor aesthetics, inability to perform oral hygiene procedures due to difficul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Masseter Muscle
In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the strongest. Structure The masseter is a thick, somewhat quadrilateral muscle, consisting of three heads, superficial, deep and coronoid. The fibers of superficial and deep heads are continuous at their insertion. Superficial head The superficial head, the larger, arises by a thick, tendinous aponeurosis from the temporal process of the zygomatic bone, and from the anterior two-thirds of the inferior border of the zygomatic arch. Its fibers pass inferior and posterior, to be inserted into the angle of the mandible and inferior half of the lateral surface of the ramus of the mandible. Deep head The deep head is much smaller, and more muscular in texture. It arises from the posterior third of the low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporalis Muscle
In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomatic arch so it covers much of the temporal bone.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 98''Temporal'' refers to the head's temples. Structure In humans, the temporalis muscle arises from the temporal fossa and the deep part of temporal fascia. This is a very broad area of attachment. It passes medial to the zygomatic arch. It forms a tendon which inserts onto the coronoid process of the mandible, with its insertion extending into the retromolar fossa posterior to the most distal mandibular molar.Human Anatomy, Jacobs, Elsevier, 2008, page 194 In other mammals, the muscle usually spans the dorsal part of the skull all the way up to the medial line. There, it may be attached to a sagittal cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrophyseter Deinodon
''Acrophyseter'' is a genus of extinct sperm whales that lived in the Late Miocene off the coast of Peru comprising two species: ''A. deinodon'' and ''A. robustus''. It is part of a group of macroraptorial sperm whales which all shared several features for the purpose of hunting large prey, such as deeply-rooted and thick teeth. ''Acrophyseter'' measured , making it the smallest raptorial sperm whale. Because of its short pointed snout, and its strong curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales. Discovery The genus ''Acrophyseter'' houses two species. The type species, ''A. deinodon'', was discovered in the Sud-Sacaco locality of the Pisco Formation in Peru, dating back to the Tortonian– Messinian stages of the Miocene around 8.5–6.7 million years ago (mya); the holotype specimen, MNHN SAS 1626, represents a mature individual and consists of a skull and jaw with most of the teeth intact. The second species, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scaldicetus
''Scaldicetus'' is an extinct genus of highly predatory macroraptorial sperm whale. Although widely used for a number of extinct physeterids with primitive dental morphology consisting of enameled teeth, ''Scaldicetus'' as generally recognized appears to be a wastebasket taxon filled with more-or-less unrelated primitive sperm whales. Taxonomy ''Scaldicetus'' is known from the Miocene to Pleistocene deposits of Western Europe, the U.S. (California, Florida, Maryland, Virginia), Baja Peninsula, Peru, New South Wales, and Japan. However, ''Scaldicetus'' is probably a grade taxon, and fossil teeth assigned to it (largely due to the lack of distinguishing characteristics in fossil teeth alone) probably represent more-or-less unrelated sperm whales united by their primitive characteristics rather than actual ancestry. Consequently, this would inflate the genus's distribution. The name ''Scaldicetus caretti'' was coined in 1867 from numerous sperm whale teeth collected in Neoge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
