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Novumbra Oregonensis
''Novumbra oregonensis'' is an extinct species of mudminnow from Oregon, USA. All fossils have been found in the lower member of the John Day Formation; the type specimens were found in the Knox Ranch leaf locality, and additional paratypes were found in the Bridge Creek flora locality. Similar to other mudminnows, its habitat would have been heavily vegetated waters, based on the presence of leaf imprints accompanying the fossils. ''Novumbra oregonensis'' differs from the only other member of the genus, the Olympic mudminnow The Olympic mudminnow (''Novumbra hubbsi'') is a fish native to the western lowlands of Washington: the Chehalis River basin, Deschutes River basin, and some Olympic Peninsula basins. It grows to 8 cm (about 3 in) in length, and is Was ..., by a larger head (the skull of the former goes into the standard length 3 times, while the latter's head goes into the standard length 3.5 times), and a significantly longer lower jaw. The pelvic, anal, and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Day Formation
The John Day Formation is a series of rock strata exposed in the Picture Gorge district of the John Day River basin and elsewhere in north-central Oregon in the United States. The Picture Gorge exposure lies east of the Blue Mountain uplift, which cuts southwest–northeast through the Horse Heaven mining district northeast of Madras. Aside from the Picture Gorge district, which defines the type, the formation is visible on the surface in two other areas: another exposure is in the Warm Springs district west of the uplift, between it and the Cascade Range, and the third is along the south side of the Ochoco Mountains. All three exposures, consisting mainly of tuffaceous sediments and pyroclastic rock rich in silica, lie unconformably between the older rocks of the Clarno Formation below and Columbia River basalts above. Stratigraphy The strata, which vary in age from 39 million years to 18 million years, were formed mainly from ashfalls from volcanoes due to a series of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olympic Mudminnow
The Olympic mudminnow (''Novumbra hubbsi'') is a fish native to the western lowlands of Washington: the Chehalis River basin, Deschutes River basin, and some Olympic Peninsula basins. It grows to 8 cm (about 3 in) in length, and is Washington's only known endemic freshwater fish species. Although they strongly resemble killifish, mudminnows are more closely related to pike and muskellunge. The Olympic mudminnow is the only living species in the genus '' Novumbra'', and one of eight living species worldwide in the paraphyletic family Umbridae. It predominantly resides in darkly stained tannic waters in the lower levels of lentic ecosystems, although may be found in clearwater swamps, and feeds on fish larvae, eggs, but more often small invertebrates. It prefers areas with mudbeds and dense vegetation, and has a remarkable tolerance for low oxygen levels. The Olympic mudminnow is listed as a sensitive species by the state of Washington. Although many populations are foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbridae
Umbridae is a family of fish in the order Esociformes, which contains pike, pickerel, and mudminnows. The single living genus, ''Umbra'', occupies weed-choked freshwater habitats in eastern North America and eastern Europe. While the family traditionally contained the genera ''Umbra'', '' Novumbra'', and ''Dallia'', recent genetic and paleontological research have recovered this grouping as paraphyletic, with ''Novumbra'' and ''Dallia'' being moved to the family Esocidae. Distribution Umbridae contains three extant species, all within the genus ''Umbra'': ''Umbra pygmaea'', ''Umbra limi'', and ''Umbra krameri''. ''U. pygmaea'' can be found across the eastern United States and southeastern Canada. ''U. limi'' ranges throughout the Great Lakes region and Mississippi River basin of North America. ''U. krameri'' can be found in the Danube and Dniester River basins of Europe. ''Umbra ''spp. are most commonly found in the Atlantic coast regions of North America, along the marshy, l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Ray-finned Fish
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
