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Nautilus Praepompilius
''Nautilus praepompilius'' is an extinct species of nautilus. It lived from the Late Paleocene through Oligocene epochs. The first fossil specimens discovered in the Late Eocene to Oligocene-aged Chegan Formation of Kazakhstan: an additional, older specimen was found in the Late or Latest Paleocene-aged Pebble Point Formation in Victoria, Australia.Ward, P. D., et al. "The Paleocene cephalopod fauna from pebble point, Victoria (Australia)-fulcrum between two Eras." (2016): 391. ''N. praepompilius'' has been grouped into a single genus together with extant species based on their shared shell characters. It is morphologically closest to '' N. pompilius'', hence the name. The nepionic constriction shows that the hatching size was approximately 23 mm, close to that for ''N. pompilius'' (around 26 mm).Ward, P.D. & W.B. Saunders 1997''Allonautilus'': a new genus of living nautiloid cephalopod and its bearing on phylogeny of the Nautilida ''Journal of Paleontology'' 71(6): 1054 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chambered Nautilus
The chambered nautilus (''Nautilus pompilius''), also called the pearly nautilus, is the best-known species of nautilus. The shell, when cut away, reveals a lining of lustrous nacre and displays a nearly perfect equiangular spiral, although it is not a golden spiral. The shell exhibits countershading, being light on the bottom and dark on top. This is to help avoid predators, because when seen from above, it blends in with the darkness of the sea, and when seen from below, it blends in with the light coming from above. The range of the chambered nautilus encompasses much of the south Pacific; It has been found near reefs and on the seafloor off of the coasts of Australia, Japan, and Micronesia. The eyes of the chambered nautilus, like those of all ''Nautilus'' species, are more primitive than those of most other cephalopods; the eye has no lens and thus is comparable to a pinhole camera. The species has about 90 cirri (referred to as "tentacles", see ) that do not have suckers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Animals Of Asia
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognised as a formal stratigraphic term, 'Tertiary' is still widely found in earth science literature and remains in informal use. Paleogene is often abbreviated "Pg" (but the United States Geological Survey uses the abbreviation PE for the Paleogene on the Survey's geologic maps). During the Paleogene, mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene Animals
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene Animals
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic 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 13C in the atmosphere was exceptionally low in comparison with the more common isotope 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 Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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