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Rehbachiella
''Rehbachiella'' is a genus of Cambrian crustacean comprising the only species ''Rehbachiella kinnekullensis''. It is a possible branchiopod from the Orsten of Sweden. Description ''Rehbachiella'' is roughly 1.7 mm long, with three pairs of cephalic appendages with curved spines pointing towards the mouth and eight to nine pairs of postmandibular appendages roughly identical to each other except for size and exopod length, together forming a filter apparatus. Unusually, ''Rehbachiella'' had over 30 larval stages and the most developed specimens found are still seemingly immature. Its thin carapace covers all limb-bearing segments, however there are five limbless segments extending past it, the most posterior bearing a furca alongside two protrusions that resemble undeveloped appendages. ''Rehbachiella'' has two compound eyes similar to its larval stages, as well as a large labrum. As many of its traits resemble those of Branchiopoda, it is tentatively placed as a stem-group br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branchiopoda
Branchiopoda, from Ancient Greek βράγχια (''bránkhia''), meaning "gill", and πούς (''poús''), meaning "foot", is a class (biology), class of crustaceans. It comprises Anostraca, fairy shrimp, clam shrimp, Diplostraca (or Cladocera), Notostraca, the Devonian ''Lepidocaris'' and possibly the Cambrian ''Rehbachiella''. They are mostly small, freshwater animals that feed on plankton and detritus. Description Members of the Branchiopoda are unified by the presence of gills on many of the animals' appendages, including some of the arthropod mouthparts, mouthparts. This is also responsible for the name of the group (from the , gills, akin to , windpipe; , foot). They generally possess compound eyes and a carapace, which may be a shell of two valves enclosing the trunk (as in most Cladocera), broad and shallow (as in the Notostraca), or entirely absent (as in the Anostraca). In the groups where the carapace prevents the use of the trunk limbs for swimming (Cladocera and clam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orsten
The Orsten fauna are fossilized organisms preserved in the Orsten lagerstätte of Cambrian (Late Miaolingian to Furongian) rocks, notably at Kinnekulle and on the island of Öland, all in Sweden. The initial site, discovered in 1975 by Klaus Müller and his assistants, exceptionally preserves soft-bodied organisms, and their larvae, who are preserved uncompacted in three dimensions. The fossils are phosphatized and silicified, thus the delicate chitinous cuticle and soft parts are not affected by acids, which act upon the limestone nodules within which the fossils have survived. Acids dissolve the limestone, revealing the microfossils in a recovery process called "acid etching". To recover the fossils, more than one and a half tons of Orsten limestone have been dissolved in acid, originally in a specifically designed laboratory in Bonn, more recently moved to Ulm. The insoluble residue is scanned by electron microscope. The phosphorus used to replace the fossils with calcium p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anostraca
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are referred to as fairy shrimp. They live in vernal pools and hypersaline lakes across the world, and they have even been found in deserts, ice-covered mountain lakes, and Antarctic ice. They are usually long (exceptionally up to ). Most species have 20 body segments, bearing 11 pairs of leaf-like ''phyllopodia'' (swimming legs), and the body lacks a carapace. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces, with the exception of '' Branchinecta gigas,'' or "giant fairy shrimp", which is itself a predator of other species of anostracans. They are an important food for many birds and fish, and some are cultured and harvested for use as fish food. There are 300 species spread across 8 families. Description The body of a fairy shrimp is elongated and divided into segments. The whole animal is typically long, but one species, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepidocaris
''Lepidocaris rhyniensis'' is an extinct species of crustacean. It is the only species known from the order Lipostraca, and is the only abundant animal in the Pragian-aged Rhynie chert deposits. It resembles modern Anostraca, to which it is probably closely related, although its relationships to other orders remain unclear. The body is long, with 23 body segments and 19 pairs of appendages, but no carapace. It occurred chiefly among charophytes, probably in alkaline vernal pool, temporary pools. Biostratigraphy and taxonomy All the known specimens of ''Lepidocaris rhyniensis'' have been excavated from the Rhynie chert deposits in Aberdeenshire, Scotland, which is a famous ', or site of exceptional preservation. ''Lepidocaris'' is the only abundant animal in the deposits, and is likely to be responsible for many of the frequent coprolites found in the rocks. ''Lepidocaris'' was species description, first described by David Joseph Scourfield, D. J. Scourfield in a 1926 paper in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinnekulle
Kinnekulle is a flat-topped mountain in the county of Västergötland, southwestern Sweden, on the eastern shore of lake Vänern. Its highest point is above sea level. The mountain is long and wide at the top. Geology Despite its enormous size, Kinnekulle is actually the smaller remnant of a much larger plateau, long ago worn down to a flat plain. Some 550 million years ago, in the Neoproterozoic, Neoproterozoic Era, the bottom-most rock of the plateau was under the sea. Layers of sedimentary rock formed over that layer from sand, mud, and sea animal remains. About 200 million years ago, during the Mesozoic, Mesozoic era, the area was uplifted above the sea. Tectonics, Tectonic activity forced molten lava through the sedimentary rock, creating sheetlike layers of diabase. These layers, when present, protected the softer sedimentary rock beneath them from erosion, resulting in mesa-like mountains such as Kinnekulle and its neighbours. History The historic town and ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Europe
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly increas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Crustacean Genera
Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins 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 years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by the 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. It is based on an old conception of history that without written records there could be no history. The most common conception today is that history is based on evidence, however the concept of prehistory hasn't been completely discarded. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Crustaceans
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
