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Carolinacetus
''Carolinacetus'' is an extinct protocetid early whale found in the Bartonian () Tupelo Bay Formation (, paleocoordinates ) in Berkeley County, South Carolina.. Retrieved July 2013. ''Carolinacetus'' is known from an incomplete cranium with portions of the right inner ear, a detached rostrum, and parts of both mandibles with 11 teeth. Preserved from the postcranium are 13 vertebrae and 15 ribs. The holotype was collected in 1994. Several anatomical features identifies ''Carolinacetus'' as a protocetid (and therefore as a member of Pelagiceti) including: external nares are located above the canine, the supraoccipital (in cetaceans, the part of the occipital bone located above the foramen magnum and directed backwards) is narrow and tubular, accessory cusps absent on M3, a broad connection between the ectotympanic bulla and the falciform process of the squamosal, axis vertebra with large vertebral foramen. In ''Carolinacetus'' the naral openings are located in front of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georgiacetus
''Georgiacetus'' is an extinct genus of ancient whale known from the Eocene period of the United States. Fossils are known from Georgia, Alabama, and Mississippi and protocetid fossils from the right time frame, but not yet confirmed as ''Georgiacetus'', have been found in Texas () and South Carolina (). created a new clade, Pelagiceti, for the common ancestor of Basilosauridae and all of its descendants, including Neoceti, the living cetaceans. He placed ''Georgiacetus'' near the base of this clade together with '' Eocetus'' and perhaps '' Babiacetus'' because of the assumed presence of a fluke and very compressed posterior caudal vertebrae in these genera. ''Georgiacetus'' is an extinct protocetid (early whale) which lived about and hunted the rich, Suwannee Current powered coastal sea which once covered the Southeastern United States. This was during the earliest Bartonian Stage of the Eocene Epoch (). Current research puts ''Georgiacetus'' as the link between the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protocetidae
Protocetidae, the protocetids, form a diverse and heterogeneous group of extinct cetaceans known from Asia, Europe, Africa, South America, and North America. Description There were many genera, and some of these are very well known (e.g., '' Rodhocetus''). Known protocetids had large fore- and hindlimbs that could support the body on land, and it is likely that they lived amphibiously: in the sea and on land. It is unclear at present whether protocetids had flukes (the horizontal tail fin of modern cetaceans). However, what is clear is that they are adapted even further to an aquatic life-style. In '' Rodhocetus'', for example, the sacrum – a bone that in land-mammals is a fusion of five vertebrae that connects the pelvis with the rest of the vertebral column – was divided into loose vertebrae. However, the pelvis retain a sacroiliac joint. Furthermore, the nasal openings are now halfway up the snout; a first step towards the telescoped condition in modern whale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeoceti
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and e ... [...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 tymp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils Of The United States
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the abso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nare
A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation. Fish do not breathe through noses, but they do have two (but cyclostomes have merged into one) small holes used for smelling, which can also be referred to as nostrils. In humans, the nasal cycle is the normal ultradian cycle of each nostril's blood vessels becoming engorged in swelling, then shrinking. The nostrils are separated by the septum. The septum can sometimes be deviated, causing one nostril to appear larger than the other. With extreme damage to the septum and columella, the two nostrils are no longer separated and form a single larger external opening. Like other tetrapods, humans have two external nostrils (anterior nares) and two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foramen
In anatomy and osteology, a foramen (; in Merriam-Webster Online Dictionary '. plural foramina, or foramens ) is an open hole that is present in extant or extinct s. Foramina inside the body of animals typically allow nerves, arteries, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axis (anatomy)
In anatomy, the axis (from Latin ''axis'', "axle") or epistropheus is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The axis' defining feature is its strong odontoid process (bony protrusion) known as the dens, which rises dorsally from the rest of the bone. Structure The body is deeper in front or in the back and is prolonged downward anteriorly to overlap the upper and front part of the third vertebra. It presents a median longitudinal ridge in front, separating two lateral depressions for the attachment of the longus colli muscles. Odontoid Process of Axis (Dens) The dens, also called the odontoid process or the peg, is the most pronounced projecting feature of the axis. The dens exhibits a slight constriction where it joins the main body of the vertebra. The condition where the dens is separated from the body of the axis is called ''os odontoideum'' and may cause nerve and circulation compression syndrom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squamosal
The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestral component of the dermal roof and is typically thin compared to other skull bones. The squamosal bone lies ventral to the temporal series and otic notch, and is bordered anteriorly by the postorbital. Posteriorly, the squamosal articulates with the quadrate and pterygoid bones. The squamosal is bordered anteroventrally by the jugal and ventrally by the quadratojugal. Function in reptiles In reptiles, the quadrate and articular bones of the skull articulate to form the jaw joint. The squamosal bone lies anterior to the quadrate bone. Anatomy in synapsids Non-mammalian synapsids In non-mammalian synapsids, the jaw is composed of four bony elements and referred to as a quadro-articular jaw because the joint is between the articular an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nare
A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation. Fish do not breathe through noses, but they do have two (but cyclostomes have merged into one) small holes used for smelling, which can also be referred to as nostrils. In humans, the nasal cycle is the normal ultradian cycle of each nostril's blood vessels becoming engorged in swelling, then shrinking. The nostrils are separated by the septum. The septum can sometimes be deviated, causing one nostril to appear larger than the other. With extreme damage to the septum and columella, the two nostrils are no longer separated and form a single larger external opening. Like other tetrapods, humans have two external nostrils (anterior nares) and two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectotympanic
The ectotympanic, or tympanicum, is a bony structure found in all mammals, located on the tympanic part of the temporal bone, which holds the tympanic membrane (eardrum) in place. In catarrhine primates (including humans), it takes a tube-shape. Its position and attachment to the skull vary between primates, and can be either inside or outside the auditory bulla. It is homologous with the angular bone of non-mammalian tetrapods Tetrapods (; ) are four-limb (anatomy), limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant taxon, extant and extinct amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (p .... References External links webref: Anthropology* * Skull Vertebrate anatomy {{Vertebrate anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
