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Zygorhiza Kochii
''Zygorhiza'' ("Yoke-Root") is an extinct genus of basilosaurid early whale known from the Late Eocene ( Priabonian, 38–34 Ma) of Louisiana, Alabama, and Mississippi, United States, and the Bartonian (43–37 Ma on the New Zealand geologic time scale) to the late Eocene of New Zealand (). Specimens reported from Europe are considered Dorudontinae ''incertae sedis''. ''Zygorhiza kochii'', along with ''Basilosaurus'' under the designation "prehistoric whales", is the state fossil of Mississippi. Taxonomic history Reichenbach (1847) erected ''Basilosaurus kochii'' for the posterior skull fragment MB Ma.43248, found in the Late Eocene (middle-late Priabonian) Ocala Limestone of Clarksville, Louisiana. Meanwhile, Muller (1851) erected a new subspecies of ''Zeuglodon brachyspondylus'', ''Z. brachyspondylus minor'', for not only MB Ma.43248 but also MB Ma.43247, TM 8501 (holotype of ''Zeuglodon hydrarchus'' Carus, 1849), and several vertebrae. In the late 19th century there was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basilosauridae
Basilosauridae is a family of extinct cetaceans. They lived during the middle to the early late Eocene and are known from all continents, including Antarctica. They were probably the first fully aquatic cetaceans.Buono M, Fordyce R.E., Marx F.G., Fernández M.S. & Reguero M. (2019). "Eocene Antarctica: a window into the earliest history of modern whales". ''Advances in Polar Science'' 30(3): p. 293-302. doi10.13679/j.advps.2019.0005/ref> The group is noted to be a paraphyletic assemblage of stem group whales from which the monophyletic Neoceti are derived. Characteristics Basilosaurids ranged in size from and were fairly similar to modern cetaceans in overall body form and function. Some genera tend to show signs of convergent evolution with mosasaurs by having long serpentine body shape, which suggests that this body plan seems to have been rather successful. Basilosaurid forelimbs have broad and fan-shaped scapulae attached to a humerus, radius, and ulna which are flatte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygorhiza
''Zygorhiza'' ("Yoke-Root") is an extinct genus of basilosaurid early whale known from the Late Eocene (Priabonian, 38–34 Ma) of Louisiana, Alabama, and Mississippi, United States, and the Bartonian (43–37 Ma on the New Zealand geologic time scale) to the late Eocene of New Zealand (). Specimens reported from Europe are considered Dorudontinae ''incertae sedis''. ''Zygorhiza kochii'', along with ''Basilosaurus'' under the designation "prehistoric whales", is the state fossil of Mississippi. Taxonomic history Reichenbach (1847) erected ''Basilosaurus kochii'' for the posterior skull fragment MB Ma.43248, found in the Late Eocene (middle-late Priabonian) Ocala Limestone of Clarksville, Louisiana. Meanwhile, Muller (1851) erected a new subspecies of ''Zeuglodon brachyspondylus'', ''Z. brachyspondylus minor'', for not only MB Ma.43248 but also MB Ma.43247, TM 8501 (holotype of ''Zeuglodon hydrarchus'' Carus, 1849), and several vertebrae. In the late 19th century there was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyoid
The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra. Unlike other bones, the hyoid is only distantly articulated to other bones by muscles or ligaments. It is the only bone in the human body that is not connected to any other bones nearby. The hyoid is anchored by muscles from the anterior, posterior and inferior directions, and aids in tongue movement and swallowing. The hyoid bone provides attachment to the muscles of the floor of the mouth and the tongue above, the larynx below, and the epiglottis and pharynx behind. Its name is derived . Structure The hyoid bone is classed as an irregular bone and consists of a central part called the body, and two pairs of horns, the greater and lesser horns. Body The body of the hyoid bone is the central part of the hyoid bone. *At the front, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Fossa
The temporal fossa is a fossa (shallow depression) on the side of the skull bounded by the temporal lines and terminating below the level of the zygomatic arch. Boundaries * Medial: frontal bone, parietal bone, temporal bone, and sphenoid bone. * Lateral: Temporal fascia * Anterior: Posterior surface of the frontal process of the zygomatic bone and the posterior surface of the zygomatic process of the frontal bone. * Superior: Pair of temporal lines (superior and inferior temporal lines) that arch across the skull from the zygomatic process of the frontal bone to the supramastoid crest of the temporal bone * Inferior: Zygomatic arch laterally and by the infratemporal crest of the greater wing of the sphenoid medially. Temporal & Infratemporal Fossa * Osteology * Temporal fossa, boundaries & contents * Infratemporal fossa, boundaries & contents * Muscles of mastication * Maxillary artery * Pterygoid venous plexus * Mandibular nerve * Temporomandibular Joint Contents * Tempo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittal Crest
A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are exceptionally strong jaw muscles. The sagittal crest serves primarily for attachment of the temporalis muscle, which is one of the main chewing muscles. Development of the sagittal crest is thought to be connected to the development of this muscle. A sagittal crest usually develops during the juvenile stage of an animal in conjunction with the growth of the temporalis muscle, as a result of convergence and gradual heightening of the temporal lines. Function A sagittal crest tends to be present on the skulls of adult animals that rely on powerful biting and clenching of their teeth, usually as a part of their hunting strategy. Skulls of some dinosaur species, including tyrannosaurs, possessed well developed sagittal crests. Among mammals, dogs, cats, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rostrum (anatomy)
Rostrum (from Latin ', meaning ''beak'') is a term used in anatomy for a number of phylogenetically unrelated structures in different groups of animals. Invertebrates * In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes. It is generally a rigid structure, but can be connected by a hinged joint, as seen in Leptostraca. * Among insects, the rostrum is the name for the piercing mouthparts of the order Hemiptera as well as those of the snow scorpionflies, among many others. The long snout of weevils is also called a rostrum. * Gastropod molluscs have a rostrum or proboscis. * Cephalopod molluscs have hard beak-like mouthparts referred to as the rostrum. File:Washington DC Zoo - Macrobrachium rosenbergii 6.jpg, Crustacean: the rostrum of the shrimp ''Macrobrachium rosenbergii'' is serrated along both edges. File:Gminatus australis with Beetle.jpg, Insect: assassin bug piercing its prey with its rostrum File:Architeuthis beak.jpg, Cephalopod: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygorhiza Kochii Teylers
''Zygorhiza'' ("Yoke-Root") is an extinct genus of basilosaurid early whale known from the Late Eocene (Priabonian, 38–34 Ma) of Louisiana, Alabama, and Mississippi, United States, and the Bartonian (43–37 Ma on the New Zealand geologic time scale) to the late Eocene of New Zealand (). Specimens reported from Europe are considered Dorudontinae ''incertae sedis''. ''Zygorhiza kochii'', along with ''Basilosaurus'' under the designation "prehistoric whales", is the state fossil of Mississippi. Taxonomic history Reichenbach (1847) erected ''Basilosaurus kochii'' for the posterior skull fragment MB Ma.43248, found in the Late Eocene (middle-late Priabonian) Ocala Limestone of Clarksville, Louisiana. Meanwhile, Muller (1851) erected a new subspecies of ''Zeuglodon brachyspondylus'', ''Z. brachyspondylus minor'', for not only MB Ma.43248 but also MB Ma.43247, TM 8501 (holotype of ''Zeuglodon hydrarchus'' Carus, 1849), and several vertebrae. In the late 19th century there was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stria
Stretch marks, also known as striae () or striae distensae, are a form of scarring on the skin with an off-color hue. Over time they may diminish, but will not disappear completely. Striae are caused by tearing of the dermis during periods of rapid growth of the body, such as during puberty or pregnancy, in which they usually form during the last trimester. Usually on the stomach, these striae also commonly occur on the breasts, thighs, hips, lower back, and buttocks. Pregnancy-related striae are known as ''striae gravidarum''. Striae may also be influenced by the hormonal changes associated with puberty, pregnancy, bodybuilding, or hormone replacement therapy. There is no evidence that creams used during pregnancy prevent stretch marks. Once they have formed there is no clearly effective treatment, though various methods have been attempted and studied. Signs and symptoms Striae, or "stretch marks", begin as reddish or purple lesions, which can appear anywhere on the body, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anastomosis
An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection may be normal (such as the foramen ovale (heart), foramen ovale in a fetus's heart) or abnormal (such as the atrial septal defect#Patent foramen ovale, patent foramen ovale in an adult's heart); it may be acquired (such as an arteriovenous fistula) or innate (such as the arteriovenous shunt of a metarteriole); and it may be natural (such as the aforementioned examples) or artificial (such as a surgical anastomosis). The reestablishment of an anastomosis that had become blocked is called a reanastomosis. Anastomoses that are abnormal, whether congenital disorder, congenital or acquired, are often called fistulas. The term is used in medicine, biology, mycology, geology, and geography. Etymology Anastomosis: medical or Modern Latin, from Gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cingulum (dentistry)
In dentistry, cingulum (Latin: girdle or belt) refers to an anatomical feature of the teeth. It refers to the portion of the teeth that forms a convex protuberance at the cervical third of the anatomic crown. It represents the lingual or palatal developmental lobe of these teeth.Ash, Major M. and Stanley J. Nelson. ''Wheeler’s Dental Anatomy, Physiology, and Occlusion.'' 8th edition. 2003. . In zoology and palaeontology, cingulum refers to this feature only in the upper teeth. When this occurs in the lower teeth it is called the cingulid A cingulid is a term used when describing teeth, it refers to a ridge that runs around the base of the crown of a lower tooth (the equivalent on the upper teeth is the cingulum). The presence or absence of a cingulid is often a diagnostic featur .... References Teeth {{dentistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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