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McKay Formation
The McKay Formation is a geologic formation in Oregon. It preserves fossils dating back to the Tortonian to Zanclean stages (Hemphillian) of the Neogene period.McKay Formation at Fossilworks.org at Fossil content [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platygonus Leptorhinus
''Platygonus'' ("flat head" in reference to the straight shape of the forehead) is an extinct genus of herbivorous peccaries of the family Tayassuidae, endemic to North and South America from the Miocene through Pleistocene epochs (10.3 million to 11,000 years ago), existing for about . ''P. compressus'' stood 2.5 feet (0.75 meters) tall. Description Most ''Platygonus'' species were similar in size to modern peccaries especially giant peccary, at around in body length, and had long legs, allowing them to run well. They also had a pig-like snout and long tusks which were probably used to fend off predators. Taxonomy While long thought to be the sister-lineage to the Chacoan peccary based on morphological similarities, a 2017 ancient DNA study which recovered mitochondrial DNA from ''Platygonus'' found that all living peccaries are more closely related to each other than they are to ''Platygonus''. The estimated divergence between ''Platygonus'' and all living peccaries wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermophilus Mckayensis
''Spermophilus'' is a genus of ground squirrels in the squirrel family. As traditionally defined the genus was very species-rich, ranging through Europe, Asia and North America, but this arrangement was found to be paraphyletic to the certainly distinct prairie dogs, marmots, and antelope squirrels. As a consequence, all the former ''Spermophilus'' species of North America have been moved to other genera, leaving the European and Asian species as true ''Spermophilus'' (the only exceptions are two Asian ''Urocitellus''). Some species are sometimes called susliks (or sousliks). This name comes from Russian суслик, ''suslik''. In some languages, a derivative of the name is in common usage, for example ''suseł'' in Polish. The scientific name of this genus means "seed-lovers" (gr. σπέρμα ''sperma'', genitive σπέρματος ''spermatos'' – seed; φίλος ''philos'' – friend, lover). Habitat and behavior As typical ground squirrels, ''Spermophilus'' live in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sciuridae
Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squirrels are indigenous to the Americas, Eurasia, and Africa, and were introduced by humans to Australia. The earliest known fossilized squirrels date from the Eocene epoch, and among other living rodent families, the squirrels are most closely related to the mountain beaver and to the dormice. Etymology The word ''squirrel'', first attested in 1327, comes from the Anglo-Norman which is from the Old French , the reflex of a Latin word , which was taken from the Ancient Greek word (; from ) 'shadow-tailed', referring to the long bushy tail which many of its members have. The native Old English word for the squirrel, , survived only into Middle English (as ) before being replaced. The Old English word is of Common Germanic origin, cognat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aplodontidae
The family Aplodontiidae also known as Aplodontidae, Haplodontiidae or Haploodontini is traditionally classified as the sole extant family of the suborder Protrogomorpha. It may be the sister family of the Sciuridae. There are fossils from the Oligocene until Miocene in Asia, from Oligocene in Europe and from the Oligocene until the present in North America, where there is the only living species: the mountain beaver (''Aplodontia rufa''). Systematics It includes the following genera: * '' Aplodontia'' Richardson, 1829 * †'' Altasciurus '' Korth, 2019 * †'' Ameniscomys'' Dehm, 1950 * †'' Ansomys'' Qiu, 1987 * †'' Dakotallomys'' Tedrow and Korth, 1999 * †'' Disallomys'' Korth, 2009 * †'' Ephemeromys'' Wang & Heissig, 1984 * †'' Haplomys'' Miller and Gidley, 1918 * †'' Leptoromys'' Tedrow and Korth, 1997 * †'' Liodontia'' Miller and Gidley, 1918 * †'' Meniscomys'' Cope, 1879 * †''Niglarodon'' Black, 1961 * †''Ninamys'' Vianey-Liaud, Rodrigues & Marivaux, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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