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Mongolarachne
''Mongolarachne'' is an extinct genus of spiders placed in the monogeneric family Mongolarachnidae. The genus contains only one species, ''Mongolarachne jurassica'', described in 2013, which is presently the largest fossilized spider on record. The type species was originally described as ''Nephila jurassica'' and placed in the living genus ''Nephila'' which contains the golden silk orb-weavers. Subsequently it was determined to be stem-orbicularian, i.e. a relative of the group Orbiculariae, which contains the family Nephilidae, but also several other families, such as Theridiidae, Theridiosomatidae or Uloboridae. The species is known only from the Middle Jurassic Jiulongshan Formation, part of the Daohugou Beds, near the village of Daohugou in Ningcheng County, northeastern China and the Yixian Formation. A second putative species, '' Mongolarachne chaoyangensis'', was described in 2019, but it was subsequently shown to be a forgery based on a fossil crayfish. Jorg W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mongolarachne Chaoyangensis
''Cricoidoscelosus'' is an extinct genus of crayfish discovered in the Yixian Formation in China, with only the type species, ''C. aethus'', known, that may be one of, if not, the oldest known fossil crayfish to date.Taylor, R.S., Schram, F.R. & Shen, Y.B. (1999) A new crayfish family (Decapoda: Astacida) from the Upper Jurassic of China, with a reinterpretation of other Chinese crayfish taxa, ''Paleontological Research'', 3, 121–136. ''Cricoidoscelosus'' was initially believed to be Late Jurassic ( Tithonian) in age, but it is now confirmed to have been Early Cretaceous (Barremian- Aptian) in age. Taxonomy "''Mongolarachne''" ''chaoyangensis'' In 2019, a supposed new species of the spider ''Mongolarachne, "Mongolarachne" chaoyangensis'' was described from the Yixian Formation in China. However, in a later publication that same year, when the specimen was subject to fluorescence microscopy A fluorescence microscope is an optical microscope that uses fluorescence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crayfish
Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mudbugs, baybugs or yabbies. Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea. They breathe through feather-like gills. Some species are found in brooks and streams, where fresh water is running, while others thrive in swamps, ditches, and paddy fields. Most crayfish cannot tolerate polluted water, although some species, such as ''Procambarus clarkii'', are hardier. Crayfish feed on animals and plants, either living or decomposing, and detritus. The term "crayfish" is applied to saltwater species in some countries. Terminology The name "crayfish" comes from the Old French word ' (Modern French '). The word has been modified to "crayfish" by association with "fish" (folk etymology). The largely American ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,British Geological Survey. 2011Stratigraphic framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf: research report RR/11/06 British Geological Survey, Keyworth, Nottingham. the Daohugou Beds in China, the Itat Formation in Russia, and the Isalo III Formation of western Madagascar. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subduction zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daohugou
The Haifanggou Formation (), also known as the Jiulongshan Formation (), is a fossil-bearing rock deposit located near Daohugou () village of Ningcheng County, in Inner Mongolia, northeastern China. The formation consists of coarse conglomerates, sandstone, mudstone, and thin coal layers deposited in deltaic and lacustrine environments. The formation dates to the Callovian of the Middle Jurassic to the Oxfordian of the Late Jurassic. The most prominent locality of the Haifanggou Formation are the Daohugou Beds, located near the village of Daohugou in southeastern Inner Mongolia. Other localities include Wuhuaxigou, Chentaizi, Jiangzhangzi, Wubaiding, Guancaishan, Haifenggou, Fanzhangzi, and Zhuanshanzi. Dating Daohugou bed The age of the Daohugou bed has been debated, and a number of studies, using different methodologies, have reached conflicting conclusions. Various papers have placed the fossils here as being anywhere from the Middle Jurassic period (169 million ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock containing 25% to 75% ash is described as tuffaceous (for example, ''tuffaceous sandstone''). Tuff composed of sandy volcanic material can be referred to as volcanic sandstone. Tuff is a relatively soft rock, so it has been used for construction since ancient times. Because it is common in Italy, the Romans used it often for construction. The Rapa Nui people used it to make most of the ''moai'' statues on Easter Island. Tuff can be classified as either igneous or sedimentary rock. It is usually studied in the context of igneous petrology, although it is sometimes described using sedimentological terms. Tuff is often erroneously called tufa in guidebooks and in television programmes. Volcanic ash The material that is expelled in a volcanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compression Fossil
A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason for this is that physical compression of the rock often leads to distortion of the fossil. The best fossils of leaves are found preserved in fine layers of sediment that have been compressed in a direction perpendicular to the plane of the deposited sediment. Since leaves are basically flat, the resulting distortion is minimal. Plant stems and other three-dimensional plant structures do not preserve as well under compression. Typically, only the basic outline and surface features are preserved in compression fossils; internal anatomy is not preserved. These fossils may be studied while still partially entombed in the sedimentary rock matrix where they are preserved, or once lifted out of the matrix by a peel or transfer technique. Compr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
