|
Eoandromeda
''Eoandromeda'' is an Ediacaran organism consisting of eight radial spiral arms, and known from two taphonomic modes: the standard Ediacara type preservation in Australia, and as carbonaceous compressions from the Doushantuo formation of China, where it is abundant. Morphology A few dozen fossil specimens are known, ranging from about 1 to 4 cm in diameter; they are circular in outline and their eight arms, with closed ends, spiral either clockwise or counterclockwise. Ridges cut across both the inside and outside of the spiral arms. The arms of the Australian individuals are longer and more tightly coiled than those of the Chinese, despite the Australian individuals not attaining as large a diameter; they are more often kinked. Affinity The organism was first interpreted as a trace fossil, and has also been considered to represent an agglutinating foraminiferan. However, the discovery of the Chinese fossils, which have preserved organic matter, ruled out these interpr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eoandromeda
''Eoandromeda'' is an Ediacaran organism consisting of eight radial spiral arms, and known from two taphonomic modes: the standard Ediacara type preservation in Australia, and as carbonaceous compressions from the Doushantuo formation of China, where it is abundant. Morphology A few dozen fossil specimens are known, ranging from about 1 to 4 cm in diameter; they are circular in outline and their eight arms, with closed ends, spiral either clockwise or counterclockwise. Ridges cut across both the inside and outside of the spiral arms. The arms of the Australian individuals are longer and more tightly coiled than those of the Chinese, despite the Australian individuals not attaining as large a diameter; they are more often kinked. Affinity The organism was first interpreted as a trace fossil, and has also been considered to represent an agglutinating foraminiferan. However, the discovery of the Chinese fossils, which have preserved organic matter, ruled out these interpr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ctenophore
Ctenophora (; ctenophore ; ) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and they are the largest animals to swim with the help of cilia. Depending on the species, adult ctenophores range from a few millimeters to in size. Only 100 to 150 species have been validated, and possibly another 25 have not been fully described and named. The textbook examples are cydippids with egg-shaped bodies and a pair of retractable tentacles fringed with tentilla ("little tentacles") that are covered with colloblasts, sticky cells that capture prey. Their bodies consist of a mass of jelly, with a layer two cells thick on the outside, and another lining the internal cavity. The phylum has a wide range of body forms, including the egg-shaped cydippids with retractable tentacles that capture prey, the flat generally combless platyct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran
The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and the beginning of the Phanerozoic Eon. It is named after the Ediacara Hills of South Australia. The Ediacaran Period's status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. Although the period takes its name from the Ediacara Hills where geologist Reg Sprigg first discovered fossils of the eponymous Ediacaran biota in 1946, the type section is located in the bed of the Enorama Creek within Brachina Gorge in the Flinders Ranges of South Australia, at . The Ediacaran marks the first appearance of widespread multicellular fauna following the end of Snowball Earth glaciation events, the so-called Ediacaran biota, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charnia
''Charnia'' is a genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture (thus exhibiting glide reflection, or opposite isometry). The genus ''Charnia'' was named after Charnwood Forest in Leicestershire, England, where the first fossilised specimen was found. ''Charnia'' is significant because it was the first Precambrian fossil to be recognized as such. The living organism grew on the sea floor and is believed to have fed on nutrients in the water. Despite ''Charnia'' fern-like appearance, it is not a photosynthetic plant or alga because the nature of the fossilbeds where specimens have been found implies that it originally lived in deep water, well below the photic zone where photosynthesis can occur. Diversity Several ''Charnia'' species were described but only the type species ''C. masoni'' is considered valid. Some specimens of ''C. masoni'' were described as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bituminous Limestone
Bituminous limestone is limestone impregnated and sometimes deeply colored with bituminous matter derived from the decomposition of animal and plant remains entombed within the mass or in its vicinity. Uses The amount of bituminous matter or asphalt in the pores of the rock is sometimes sufficient to permit the material being used for asphalt pavements after simply powdering and heating it. Still better results are obtained by mixing it with bituminous sandstone. Sources In the United States, bituminous limestone has been found in Oklahoma, Texas, and Utah. Much bituminous limestone was also mined in Germany, Switzerland, and France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ..., from where large quantities of it were exported to the United States. Notes References *{{NIE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbial Mat
A microbial mat is a multi-layered sheet of microorganisms, mainly bacteria and archaea, or bacteria alone. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few survive in deserts. A few are found as endosymbionts of animals. Although only a few centimetres thick at most, microbial mats create a wide range of internal chemical environments, and hence generally consist of layers of microorganisms that can feed on or at least tolerate the dominant chemicals at their level and which are usually of closely related species. In moist conditions mats are usually held together by slimy substances secreted by the microorganisms. In many cases some of the bacteria form tangled webs of filaments which make the mat tougher. The best known physical forms are flat mats and stubby pillars called stromatolites, but there are also spherical forms. Microbial mats are the earliest form of life on Earth for which there is good fossi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeopascichnus
''Palaeopascichnus'' is an Ediacaran fossil comprising a series of lobes, first originating before the Gaskiers glaciation; it is plausibly a protozoan, but probably unrelated to the classical ' Ediacaran biota'. Once thought to represent a trace fossil, it is now recognized as a body fossil and corresponds to the skeleton of an agglutinating organism. See also * List of Ediacaran genera This is a list of all described Ediacaran genera, including the Ediacaran biota. It contains 227 genera. References {{reflist, 30em * Ediacaran The Ediacaran Period ( ) is a geological period that spans 96 million years from the end ... * Palaeopascichnid References Ediacaran life Incertae sedis Ediacaran Europe Geology of Ukraine {{Ediacaran-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hiemalora
''Hiemalora'' is a fossil of the Ediacaran biota, reaching around 3 cm in diameter, which superficially resembles a sea anemone. The genus has a sack-like body with faint radiating lines originally interpreted as tentacles, but discovery of a frond-like structure seemingly attached to some ''Heimalora'' has added weight to a competing interpretation: that it represents the holdfast of a larger organism. In 2020, a new study was published that described nine different from the Indreelva member, Digermulen Peninsula, Finnmark (Arctic Norway). The specimens described in the paper have high degrees of variation between morphologies and within the specimens that are though to be of the same species. Some of the representative fossils from that paper either show multiple Aspidella-like structures on the same specimen, or a Primocandelabrum-like cone visible in one of the fossils. All of the examples of fossils in the publication were determined to most likely represent the spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tribrachidium
''Tribrachidium heraldicum'' is a tri-radially symmetric fossil animal that lived in the late Ediacaran (Vendian) seas. In life, it was hemispherical in form. ''T. heraldicum'' is the best known member of the extinct group Trilobozoa. Etymology The generic name ''Tribrachidium'' is derived from combination of the grc, τρία (, "three") + la, brachium ("arm") + diminutive suffix . The specific name ''T. heraldicum'' references the similarity of the pattern of this fossil with the well-known heraldic triskelion design, such as the coat of arms of the Isle of Man. Occurrence ''Tribrachidium'' fossils were first discovered in the Ediacara Member of the Rawnslay Quartzite, Flinders Ranges in South Australia. This fossil is also known from the Mogilev Formation in the Dniester River Basin, Podolia, Ukraine and from the Verkhovka, Zimnegory and Yorga Formations in the White Sea area of the Arkhangelsk Region, Russia. Description ''T. heraldicum'' is preserved as negative impressio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rangea
''Rangea'' is a frond-like Ediacaran fossil with six-fold radial symmetry. It is the type genus of the rangeomorphs. ''Rangea'' was the first complex Precambrian macrofossil named and described anywhere in the world. ''Rangea'' was a centimetre- to decimetre-scale frond characterised by a repetitive pattern of self-similar branches and a sessile benthic lifestyle. Fossils are typically preserved as moulds and casts exposing only a leafy petalodium, and the rarity and incompleteness of specimens has made it difficult to reconstruct the three-dimensional (3D) morphology of the entire organism.Sharp, Alana C., Alistair R. Evans, Siobhan A. Wilson, and Patricia Vickers-Rich. "First Non-destructive Internal Imaging of Rangea, an Icon of Complex Ediacaran Life." Precambrian Research 299 (2017): 303-08. doi: 10.1016/j.precamres.2017.07.023 Fossilized ''Rangea'' consists of several vanes. Each vane has a foliate shape with a series of recessed furrows that run outwards at varying angles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pteridinium
''Pteridinium'' is an erniettomorph found in a number of Precambrian deposits worldwide. It is a member of the Ediacaran biota. Body plan The three-lobed body is generally flat such that only two lobes are visible. Each lobe consists of a number of parallel ribs extending back to the main axis where the three lobes come together. Even on well-preserved specimens, there is no sign of a mouth, anus, eyes, legs, antennae, or any other appendages or organs. The organism grew primarily by the addition of new units, probably at both ends, with the inflation of existing units contributing little to its growth. Ecology Specimens found in what is thought to be life positions indicate that the creature rested on — or possibly in — the sediment in shallow seas. No tracks are known that would seem to be consistent with a moving ''Pteridinium''. It is unclear whether it performed photosynthesis, or osmotically extracted nutrients from seawater. Occurrence Fossils are common in late Preca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
