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Dhedacetus
''Dhedacetus hyaeni'' is a protocetid cetacean from the middle Eocene (late Lutetian, 42 mya). It is the only species in the genus ''Dhedacetus''. The type specimen was recovered from the Indian Harudi Formation near the town of Dhedadi, Kutch. Description Only one skull and some vertebra are known. ''D. hyaeni'' is the smallest protocetid from Kutch. Its premolars and molars are about the same size as in other protocetids such as Babiacetus, Rodhocetus and Maiacetus. It has a long, broad snout and high ocular orbits. The genus name comes from the town close by and the species name comes from a local hyena Hyenas, or hyaenas (from Ancient Greek , ), are feliform carnivoran mammals of the family Hyaenidae . With only four extant species (each in its own genus), it is the fifth-smallest family in the Carnivora and one of the smallest in the clas .... References {{Archaeoceti Protocetidae Fossil taxa described in 2014 Prehistoric cetacean genera Fossils of India ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protocetid
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 whales. Th ... [...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 whales. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). 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'', "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 Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 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 Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Thewissen
Hans Thewissen is a Dutch-American paleontologist. His field work has discovered fossils for the steps in the transition from land to water in whales: '' Ambulocetus'', '' Pakicetus'', ''Indohyus'' and '' Kutchicetus''. He now studies modern bowhead and beluga whales in Alaska to learn about their biology and their implications for management and conservation. Early life Thewissen has always been interested in paleontology and natural history. His mother said that when Thewissen was a small boy, she had to sort through his pockets before laundry time to take out the rocks and worms he collected. His father used to take him to the town of Maastricht, and they collected fossils from the Maastrichtian period. 12th birthday present was a rock hammer, which has accompanied him on all collecting trips since. He grew up just 2 miles from Liessel, a fossil locale that yielded the first whales he ever collected. Educational background After finishing Gymnasium secondary education in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cetacean
Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver. While the majority of cetaceans live in marine environments, a small number exclusively reside in brackish water or fresh water. Having a cosmopolitan distribution, they can be found in some rivers and all of Earth's oceans, and many species inhabit vast ranges where they migrate with the changing of the seasons. Cetaceans are famous for their high intelligence and complex social behaviour as well as for the enormous size of some of the group's members, such as the blue whale which reaches a maximum confirmed length of 29.9 meters (98 feet) and a weight of 173 tonnes (190 short tons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lutetian
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene Subepoch. Stratigraphic definition The Lutetian was named after Lutetia, the Latin name for the city of Paris. The Lutetian Stage was introduced in scientific literature by French geologist Albert de Lapparent in 1883 and revised by A. Blondeau in 1981. The base of the Lutetian Stage is at the first appearance of the nanofossil ''Blackites inflatus'', according to an official reference profile (GSSP) established in 2011. Of two candidates located in Spain, the Gorrondatxe section was chosen.See thwebsite of Eustoquio Molinafor these candidates. The top of the Lutetian (the base of the Bartonian) is at the first appearance of calcareous nanoplankton species ''Reticulofenestra reticulata''. The Lutetian overlaps with the Geisel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Babiacetus
''Babiacetus'' is an extinct genus of early cetacean that lived during the late Lutetian middle Eocene of India ().. Retrieved April 2013. It was named after its type locality, the Harudi Formation in the Babia Hills (: paleocoordinates ), Kutch District, Gujarat, India. ''Babiacetus'' was named by in an abstract based on the specimen's type (GSI 19647, left and right dentaries with cheek teeth). Gingerich and colleagues found a skull (GSP-UM 3005, much of a skull and lower jaws) while collecting a skeleton of a new species of Protosiren (''Protosiren sattaensis'') in the Drazinda Formation (, paleocoordinates ) in the Sulaiman Range of Punjab, Pakistan. described both the original find and their new specimen. described '' B. mishrai'' from the specimen (RUSB 2512, a partial skull) collected in the Harudi Formation.. Retrieved March 2013. ''Babiacetus'' is one of the larger protocetids. Its hydrodynamic skull and pointed, anteroposteriorly (front-back) oriented incisor ... [...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 mesonychids, an extinct group of cursorial, wolf-like ungulates, was generally accepted based on morphological analyses. In the late 1990s, however, cladistic analyses based on molecula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maiacetus
''Maiacetus'' ("mother whale") is a genus of early middle Eocene (c. 47.5 mya) cetacean from the Habib Rahi Formation of Pakistan. Paleobiology The genus contains a single species, ''Maiacetus inuus'', first described in 2009 on the basis of two specimens, including a specimen which has been interpreted as a pregnant female and its fetus. This represents the first description of a fetal skeleton of an archaeocete. The position of the fetus (head-first) suggests that the animal gave birth on land."Earliest whales gave birth on land" '''', 3 February 2009 Modern whales generally give birth tail first, while land mammals give birth head first. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyena
Hyenas, or hyaenas (from Ancient Greek , ), are feliform carnivoran mammals of the family Hyaenidae . With only four extant species (each in its own genus), it is the fifth-smallest family in the Carnivora and one of the smallest in the class Mammalia. Despite their low diversity, hyenas are unique and vital components of most African ecosystems. Although phylogenetically closer to felines and viverrids, as part of suborder Feliformia, hyenas are behaviourally and morphologically similar to canids in several elements due to convergent evolution; both hyenas and canines are non-arboreal, cursorial hunters that catch prey with their teeth rather than claws. Both eat food quickly and may store it, and their calloused feet with large, blunt, nonretractable claws are adapted for running and making sharp turns. However, hyenas' grooming, scent marking, defecation habits, mating and parental behavior are consistent with the behavior of other feliforms. Hyenas feature prominently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
