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Oxyclaenus
''Oxyclaenus'' is a genus of arctocyonid from the Lower Palaeocene of North America. Originally named as a subgenus of ''Mioclaenus'', it is now regarded as a genus of its own. Three species (the type species ''O. cuspidatus'', ''O. simplex'' and ''O. antiquus''), are known, though several more have been named over the decades. Taxonomy Early history The genus ''Oxyclaenus'' was originally erected by Edward Drinker Cope in 1884, as one of two subgenera of '' Mioclaenus''. It was distinguished from the other subgenus, conventional ''Mioclaenus'', by the lack of an internal tubercle on the third premolar. Three species, ''O, cuspidatus'', ''O. simplex'' and the now-invalid ''O. ferox'', were also assigned to ''Oxyclaenus''. The type, ''O. cuspidatus'', was distinguished from ''Mioclaenus'' by having molars that were wider transversely (diagonally) than anteroposteriorly (from front-to-back). ''Oxyclaenus'' was elevated to genus level by William Berryman Scott in 1892, who crea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctocyonidae
Arctocyonidae (from Greek ''arktos'' and ''kyôn'', "bear/dog-like") is an extinct, possibly polyphyletic family of placental mammals which lived from the late Cretaceous to the early Eocene. They were initially regarded as creodonts, though have since been reassigned to an order of their own, the Arctocyonia. Some have suggested that arctocyonids are ancestral to modern-day artiodactyls, or that they form a sister group. However, more recent phylogenetic analyses suggest that arctocyonids may represent an artificial grouping of extinct ungulates, or that they might be an assemblage of unrelated placentals related to pangolins, pantodonts, and periptychids. Members of Arctocyonidae are characterised by long skulls, with large sagittal crests and very large canines. In the case of '' Arctocyon'' proper, the lower canines especially were large enough to require a diastema on the upper jaw to accommodate them. Arctocyonids varied considerably in size and morphology. Smaller gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loxolophus
''Loxolophus'' is a genus of large arctocyonid from the early Palaeocene of North America. Two species are currently recognised: the type species, ''Loxolophus hyattianus'', and ''L. priscus''. Taxonomy Early history The holotype of ''Loxolophus'' (AMNH 3121), a fragment of the left maxilla, was formally described by Edward Drinker Cope in 1885. Cope initially assigned it to '' Chriacus'', and gave it the binomial name ''C. hyattianus''. In the same paper, a single page later, he described ''Loxolophus adapinus.'' Subsequently, they turned out to represent the same taxon, which at some point thereafter was recombined as ''Loxolophus hyattianus''. A second species, ''L. priscus'', was named three years after the initial paper, also by Cope, who similarly assigned it to ''Chriacus''. Subsequently, it was reassigned to ''Protochriacus'' by William Berryman Scott in 1892, then synonymised with ''Chriacus pugnax'' by George Gaylord Simpson in 1935, and finally was assigned to '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeocene
The Paleocene ( ), or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact (Chicxulub impact) and possibly volcanism ( Deccan Traps), marked the beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. In the Paleocene, the continents of the Northern Hemispher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Lewis Gazin
Charles Lewis Gazin (1904—1995) was an American vertebrate paleontologist and paleobiology, paleobiologist. Biography Gazin was born in Colorado in 1904. He was close friends with the physicist Carl David Anderson, Carl Anderson from an early age. Both men attended California Institute of Technology together for bachelor's and graduate education and received their doctorates on the same day in 1930. During the same year he began working for the United States Geological Survey. He was named Assistant Curator in the Division of Vertebrate Paleontology at the Smithsonian Institution in 1932. Ten years later, in 1942 he became Associate Curator and in 1946, a Curator of the Division. He was named Senior Paleobiologist in 1967, and when his retirement came in 1970, he got a Paleobiologist Emeritus position. Twelve years later in 1982 he became a Curator Emeritus. He wrote ninety-nine works on vertebrate paleontology, most of which were focused on mammalian paleontology. Gazin serve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
