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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] |
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] |
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] |
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] |
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] |
Shoulder Blade
The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side of the body being roughly a mirror image of the other. The name derives from the Classical Latin word for trowel or small shovel, which it was thought to resemble. In compound terms, the prefix omo- is used for the shoulder blade in medical terminology. This prefix is derived from ὦμος (ōmos), the Ancient Greek word for shoulder, and is cognate with the Latin , which in Latin signifies either the shoulder or the upper arm bone. The scapula forms the back of the shoulder girdle. In humans, it is a flat bone, roughly triangular in shape, placed on a posterolateral aspect of the thoracic cage. Structure The scapula is a thick, flat bone lying on the thoracic wall that provides an attachment for three groups of muscles: intrins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Bulla
The tympanic part of the temporal bone is a curved plate of bone lying below the squamous part of the temporal bone, in front of the mastoid process, and surrounding the external part of the ear canal. It originates as a separate bone (tympanic bone), which in some mammals stays separate through life. Evolutionarily, a portion of it is derived from the angular bone of the reptilian lower jaw. Surfaces Its postero-superior surface is concave, and forms the anterior wall, the floor, and part of the posterior wall of the bony ear canal. Medially, it presents a narrow furrow, the ''tympanic sulcus'', for the attachment of the tympanic membrane. Its antero-inferior surface is quadrilateral and slightly concave; it constitutes the posterior boundary of the mandibular fossa, and is in contact with the retromandibular part of the parotid gland. Borders Its lateral border is free and rough, and gives attachment to the cartilaginous part of the ear canal. Internally, the tympani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeocete
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] |
Neck Vertebra
In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid species, the cervical vertebrae bear cervical ribs. In lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The vertebral transverse processes of mammals are homologous to the cervical ribs of other amniotes. Most mammals have seven cervical vertebrae, with the only three known exceptions being the manatee with six, the two-toed sloth with five or six, and the three-toed sloth with nine. In humans, cervical vertebrae are the smallest of the true vertebrae and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process, through which the vertebral artery, vertebral veins, and in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracic Vertebra
In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical and lumbar vertebrae; they increase in size going towards the lumbar vertebrae, with the lower ones being much larger than the upper. They are distinguished by the presence of facets on the sides of the bodies for articulation with the heads of the ribs, as well as facets on the transverse processes of all, except the eleventh and twelfth, for articulation with the tubercles of the ribs. By convention, the human thoracic vertebrae are numbered T1–T12, with the first one (T1) located closest to the skull and the others going down the spine toward the lumbar region. General characteristics These are the general characteristics of the second through eighth thoracic vertebrae. The first and ninth through twelfth vertebrae contain certain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Oligocene
The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage of the Miocene). Stratigraphic definition The Chattian was introduced by Austrian palaeontologist Theodor Fuchs in 1894. Fuchs named the stage after the Chatti, a Germanic tribe.Berry, Edward W"The Mayence Basin, a Chapter of Geologic History" ''The Scientific Monthly'', Vol. 16, No. 2, February 1923. pp. 114. Retrieved March 18, 2020. The original type locality was near the German city of Kassel. The base of the Chattian is at the extinction of the foram genus ''Chiloguembelina'' (which is also the base of foram biozone P21b). An official GSSP for the Chattian Stage was ratified in October of 2016. The top of the Chattian Stage (which is the base of the Aquitanian Stage, Miocene Series and Neogene System) is at the first appearance of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elbow Joint
The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the medial epicondyles of the humerus. The elbow joint is a hinge joint between the arm and the forearm; more specifically between the humerus in the upper arm and the radius and ulna in the forearm which allows the forearm and hand to be moved towards and away from the body. The term ''elbow'' is specifically used for humans and other primates, and in other vertebrates forelimb plus joint is used. The name for the elbow in Latin is ''cubitus'', and so the word cubital is used in some elbow-related terms, as in ''cubital nodes'' for example. Structure Joint The elbow joint has three different portions surrounded by a common joint capsule. These are joints between the three bones of the elbow, the humerus of the upper arm, and the radius and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blowhole (anatomy)
In cetology, the study of whales and other cetaceans, a blowhole is the hole (or spiracle) at the top of the head through which the animal breathes air. In baleen whales, these are in pairs. It is homologous with the nostril of other mammals, and evolved via gradual movement of the nostrils to the top of the head. The posterior placement of blowholes on cetacean heads is believed to minimize the energy used when breathing at the water's surface. As whales reach the water surface to breathe, they forcefully expel air through the blowhole. The exhalation is released into the comparably lower-pressure, colder atmosphere, and any water vapor condenses. This spray, known as the ''blow'', is often visible from far away as a white splash, which can also be caused by water resting on top of the blowhole. Purpose and mechanism Air sacs just below the blowhole allow whales to produce sounds for communication and, for toothed whales, echolocation. These air sacs are filled with air, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
