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Macroraptorial Sperm Whale
Macroraptorial sperm whales were highly predatory whales of the sperm whale superfamily (Physeteroidea) of the Miocene epoch (geology), epoch that hunted large marine mammals, including other whales, using their large teeth. They consist of six genera: ''Acrophyseter'', ''Albicetus'', ''Brygmophyseter'', ''Livyatan'', ''Scaldicetus'', and ''Zygophyseter''. All species are known by at least a skull, and are informally grouped without a family (biology), 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 . The term "macroraptorial" combines the prefixes "macro-", derived from the Greek "makros" (μακρός) (meaning "long", "large" or "great") and "raptorial" from both the Latin "rapere" (ra.pi.o and räpio) and (ra.pi.o and räːpio) and "raptus" (rap.tʊs and räpt̪ʊs̠) and (rap.tus and räpt̪us) in both Classica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Livyatan Melvillei Skull
''Livyatan'' is an extinct genus of macroraptorial Physeteroidea, sperm whale containing one known species: ''L. melvillei''. The genus name was inspired by the Bible, 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. Herman Melville often referred to whales as "Leviathans" in his book. It is mainly known from the Pisco Formation of Peru during the Tortonian stage of the Miocene Epoch (geology), epoch, about 9.9–8.9 million years ago (mya); however, finds of isolated teeth from other locations such as Chile, Argentina, the United States (California), South Africa and Australia imply that either it or a close relative survived into the Pliocene, around 5mya, and may have had a global presence. 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 rapto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bessho Formation
Bessho may refer to; Places * Bessho, a mountain in Norway *Bessho Station (Shiga), Japanese railway station *Ueda Electric Railway Bessho Line, Japanese railway line *Himeji-Bessho Station, Japanese railway station *Bessho Station (Hyōgo) was a railway station in Miki, Hyōgo Prefecture, Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends ..., Japanese railway station People * Bessho (surname) {{dab, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longissimus Muscle
The longissimus () 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 cervicis (transversal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multifidus Muscle
The multifidus (multifidus spinae; : ''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 located between the thoracic vertebrae and pelvis. They form the lower part of the back in humans, and the tail end of the back in quadrupeds. In humans, there are five lumbar vertebrae. The term is used to describe the anatomy of humans and quadrupeds, such as horses, pigs, or cattle. These bones are found in particular cuts of meat, including tenderloin or sirloin steak. Human anatomy In human anatomy, the five vertebrae are 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. General characteristics The adjacent figure depicts the general charac ... [...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 difficu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Masseter Muscle
In 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 zygomatic process of the maxilla, 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 t ... [...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 cres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrophyseter Deinodon
''Acrophyseter'' is a genus of extinct sperm whale that lived in the Late Miocene off the coast of what is now Peru. The genus comprises two species: ''A. deinodon'' and ''A. robustus''. It is part of a group of macroraptorial sperm whales that all share several features for hunting large prey, such as deeply rooted and thick teeth. ''Acrophyseter'' measured in length, making it the smallest macroraptorial sperm whale currently known. Because of its short pointed snout and strongly curved front teeth, it probably fed on the marine vertebrates of its time, such as seals and other whales. History of discovery All known fossils of ''Acrophyseter'', including those of the two named species, were discovered in the Pisco Formation, located in southern Peru. The type species, ''A. deinodon'', was described in 2008 by Olivier Lambert, Giovanni Bianucci and Christian De Muizon from a skull, catalogued MNHN SAS 1626, discovered in the Sud-Sacaco locality. This site is dated between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walrus
The walrus (''Odobenus rosmarus'') is a large pinniped marine mammal with discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. It is the only extant species in the family Odobenidae and genus ''Odobenus''. This species is subdivided into two subspecies: the Atlantic walrus (''O. r. rosmarus''), which lives in the Atlantic Ocean, and the Pacific walrus (''O. r. divergens''), which lives in the Pacific Ocean. Adult walrus are characterised by prominent tusks and whiskers, and considerable bulk: adult males in the Pacific can weigh more than and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walrus live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic bivalve molluscs. Walruses are relatively long-lived, social animals, and are considered to be a " keystone species" in the Arctic marine regio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ontocetus
''Ontocetus'' is an extinct genus of walrus, an aquatic carnivoran of the family Odobenidae, endemic to coastal regions of the southern North Sea and the southeastern coastal regions of the U.S. during the Miocene-Pleistocene. It lived from 13.6 mya—300,000 years ago, existing for approximately . Taxonomy The type species, ''Ontocetus emmonsi'', was named by Joseph Leidy in 1859 on the basis of a single tusk-like tooth (USNM 329064) collected by Ebenezer Emmons from the early Pliocene ( Zanclean) Yorktown Formation of North Carolina. In the meantime, marine mammals fossils were being unearthed in Neogene deposits in the vicinity of Antwerp, Belgium as well as Suffolk, England. One of these fossils was identified as an odobenid and named ''Alachtherium cretsii.'' in 1867. An isolated tooth (RBINS 2892) was named ''Trichechodon koninckii'' in 1871. The fossils from Suffolk were named ''Trichechodon huxleyi'' in 1865. For decades, however, ''Ontocetus'' was tossed aside as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
