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Qaisracetus
''Qaisracetus'' is an extinct protocetid early whale known from the Eocene (Lutetian, ) of Baluchistan, Pakistan (, paleocoordinates ). Etymology The genus is named after the Qaisrani Baloch tribe which assisted Gingerich and his team during their field work. "Qaisra" is also etymologically close to the royal title used in Persian and many Indo-European languages (e.g. Kaiser, Czar, Caesar). The species is named for Muhammad Arif, former paleontologist at the Geological Survey of Pakistan who contributed significantly to archaeocete paleontology in Pakistan. Description ''Qaisracetus'' is known from a dozen specimens, all found in or near the type locality. Among them are several well-preserved elements, including a well-preserved skull, partial skulls and braincases, several vertebrae including an almost complete sacrum, a left innominate, ribs, and partial limb elements. ''Qaisracetus'' is smaller than '' Pappocetus'' and ''Babiacetus'' but larger than ''Indocetus''. ''Q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protocetidae
Protocetidae, the protocetids, form a paraphyletic, 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 mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeoceti
Archaeoceti ("ancient whales"), or Zeuglodontes in older literature, is an obsolete 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 capabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodhocetus
''Rodhocetus'' (from ''Rodho'', the geological anticline at the type locality, and ''cetus'', Latin for whale) is an extinct genus of protocetid early whale known from the Lutetian of Pakistan. The best-known protocetid, ''Rodhocetus'' is known from two partial skeletons that taken together give a complete image of an Eocene whale that had short limbs with long hands and feet that were probably webbed and a sacrum that was immobile with four partially fused sacral vertebrae. It is one of several extinct whale genera that possess land mammal characteristics, thus demonstrating the evolutionary transition from land to sea. Description left, Size of ''Rodhocetus'' relative to a human. ''Rodhocetus'' was a small whale measuring long. Throughout the 1990s, a close relationship between cetaceans and mesonychians, an extinct group of cursorial, wolf-like ungulates, was generally accepted based on morphological analyses. In the late 1990s, however, cladistic analyses based on molec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocetus
''Eocetus'' is an extinct Protocetidae, protocetid Archaeoceti, early whale known from the early-late Eocene (Bartonian, ) Giushi Formation in Mokattam, Gebel Mokattam, (, paleocoordinates ) outside Cairo, Egypt. Fossil remains have also been discovered in the List of fossiliferous stratigraphic units in Western Sahara, Aridal Formation of the Sahara, Sahara Desert in southwestern Morocco. The type specimen was first named by Eberhard Fraas, Fraas as ''Mesocetus schweinfurthi''. However, the name ''Mesocetus'' was previously used causing a change to the species name to ''Eocetus schweinfurthi''. Since the genus was first described in the early 20th century, several other specimens, mostly isolated vertebrae, have been attributed to ''Eocetus'', but the taxonomic status of these widely distributed specimens remain disputed. Discovery and taxonomy described "''Mesocetus schweinfurthi''" based on a dorsoventrally compressed skull with only I2 ''in situ'', a specimen supposedly ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaviacetus
''Gaviacetus'' (from Latin ''Gavia'', "loon" and ''cetus'', "whale") is an extinct archaeocete whale that lived approximately . ''Gaviacetus'' was named for its characteristic narrow rostrum and the fast pursuit predation suggested by its unfused sacral vertebrae. Location The only known ''Gaviacetus razai'' specimen was found in Punjab, Pakistan. (, paleocoordinates ) Description The skull of ''Gaviacetus'' is characteristic of protocetids, but the rostrum is extremely narrow anterior to P3, suggesting some kind of trophic specialization. The well-preserved auditory bulla in 's specimen is dense like in other archaeocetes, is equipped with a prominent sigmoid process, but has 3-5 contacts with the rest of the cranium. Preserved alveoli (tooth sockets) show that ''Gaviacetus'' had double- and triple-rooted cheek teeth, but some controversy remains regarding the number of molars. Based on other cranial characters, concluded that ''Gaviacetus'' is a protocetid (more primitiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natchitochia
''Natchitochia'' is an extinct protocetid early whale known from the Middle Eocene (Bartonian, ) Cook Mountain Formation in Natchitoches Parish, Louisiana (, paleocoordinates ).. Retrieved July 2013. ''Natchitochia'' is known from three incomplete ribs and thirteen vertebrae of which four are thoracics, five lumbars, one sacral, two caudals, and one of indeterminable position. ''Natchitochia'' is significantly larger than most other early protocetids, except ''Eocetus'' and '' Pappocetus''. The vertebrae of ''Natchitochia'' are smaller than those of ''Eocetus'' and lack (1) elongated lumbar centra and (2) the ventral keel seen on the vertebrae of ''Pappocetus''. The ribs are smaller than those of ''Pappocetus''. The fragmentary specimen was collected in 1943 during a ground water survey and then sent to the United States National Museum where Remington Kellogg Arthur Remington Kellogg (5 October 1892 – 8 May 1969) was an American naturalist and a director of the United ... [...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 proto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachyostosis
Pachyostosis is a non-pathological condition in vertebrate animals in which the bones experience a thickening, generally caused by extra layers of lamellar bone. It often occurs together with bone densification ( osteosclerosis), reducing inner cavities. This joint occurrence is called pachyosteosclerosis. However, especially in the older literature, "pachyostosis" is often used loosely, referring to all osseous specializations characterized by an increase in bone compactness and/or volume. It occurs in both terrestrial and, especially, aquatic or semi-aquatic vertebrates. In aquatic animals, such as seacows (manatees and dugongs), ''Thalassocnus'', and plesiosaurs, pachyostosis in the thoracic region provides (or provided) ballast against the air-filled lungs. This maintains neutral buoyancy in aquatic habitats. Most giant deer showed pronounced pachyostosis of the mandible and skull. It has been suggested that this served to store minerals for antler growth. Many Pachycephal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." 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 isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel Phenotypic trait, character or character state that has evolution, evolved from its ancestral form (or Plesiomorphy and symplesiomorphy, plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxon, taxa and is therefore Hypothesis#Scientific hypothesis, hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies Homology (biology), homology. Examples of apomorphy are the presence of Terrestrial locomotion#Posture, erect gait, fur, Evolution of mammalian auditory ossicles, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a Terrestrial locomotion#Posture, sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protocetus
''Protocetus atavus'' ("first whale") is an extinct species of primitive cetacean from Egypt. It lived during the middle Eocene period 45 million years ago. The first discovered protocetid, ''Protocetus atavus'' was described by based on a cranium and a number of associated vertebrae and ribs found in middle Lutetian Tethys Ocean, Tethyan marine limestone from the Mokattam Formation at Gebel Mokattam near Cairo, Egypt. Description ''Protocetus'' are believed to have had a streamlined, whale-like body around long, but was probably primitive in some respects.Palmer D (ed.) (1999). ''The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals''. London: Marshall Editions. p. 230. . Many protocetids (like ''Maiacetus'', ''Rodhocetus'') possessed well developed Hip bone, innominates and hind limbs, often attached to the backbone with a sacrum. ''Protocetus'' are known to have had at least one sacral vertebrate,Gingerich P.D. (2010). "Cetacea". In Werdelin L & Sand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Microwear
Dental microwear analysis is a method to infer diet and behavior in extinct animals, especially in fossil specimens. It has been used on a variety of taxa, including hominids, victoriapithecids, amphicyonids, canids, ursids, hyaenids, hyaenodontids, equids, rhinocerotids, moschids, tragulids, diprotodontids, varanids, and elasmobranchs. Typically, the patterns of pits and scratches on the occlusal or buccal surface of the enamel are compared with patterns observed in extant species to infer ecological information. Hard foods in particular can lead to distinctive patterns (although see below). Microwear can also be used for inferring behavior, especially those related to the non-masticatory use of teeth as 'tools'. Other uses include investigating weaning in past populations. Methods used to collect data initially involved a microscope and manually collecting information on individual microwear features, but software to automatically collect data have improved markedly in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
