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Forfexicaris
''Forfexicaris valida'' is a species of Lower Cambrian arthropod, the only species in the family Forfexicarididae. It is known from only two specimens from the Maotianshan shale '. Description ''F. valida'' had a bivalved carapace, like that seen in ostracod crustaceans, which was long and high. It had a pair of stalked eyes, and a pair of great appendage Great appendages are claw-like appendages which attach to the heads of the "great appendage arthropods", a name usually refers to Megacheira, a class of extinct arthropod characterized by a pair of "short-great appendages" bearing in front of the ...s, which closely resemble those of '' Occacaris''. References Prehistoric arthropod genera Cambrian arthropods Maotianshan shales fossils {{paleo-arthropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occacaris
''Occacaris oviformis'' is an extinct nektonic predatory arthropod from the Lower Cambrian Maotianshan shale Lagerstätte. It bears a superficial resemblance to the Cambrian arthropod, ''Canadaspis'', though, was much smaller, and had a pair of "great appendages", with which it may have grasped prey. It was originally considered to belong to Megacheira, however it is questioned in later study. It had a bivalved carapace that covered most of its body, leaving only the last two tergites of its trunk, with the telson jutting out of the posterior end of the carapace, and the eyes, antennae (possibly isolated endopod), and great appendages jutting out of the anterior end. The spines of the great appendages are paired, setting it apart from '' Forfexicaris valida'' and megacheirans like '' Fortiforceps foliosa''. Suggestions have been made that ''Occacaris'' is closely related to megacheirans, or to mandibulates. See also * Arthropod * Cambrian explosion * Chengjiang biota ** Li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Paleontology
The ''Journal of Paleontology'' is a peer-reviewed scientific journal covering the field of paleontology. It is published by the Paleontological Society. Indexing The ''Journal of Paleontology'' is indexed in: *BIOSIS Previews *Science Citation Index *The Zoological Record *GeoRef __NOTOC__ The GeoRef database is a bibliographic database that indexes scientific literature in the geosciences, including geology. Coverage ranges from 1666 to the present for North American literature, and 1933 to the present for the rest of t ... References Paleontology journals Publications established in 1927 Academic journals published by learned and professional societies Cambridge University Press academic journals Bimonthly journals Paleontological Society {{paleo-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Cambrian
The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arthropod cuticle, cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an exoskeleton, external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior Organ (anatomy), organs; it has an open circulatory system. Like their exteriors, the internal or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maotianshan Shale
The Maotianshan Shales are a series of Early Cambrian deposits in the Chiungchussu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales form one of some forty Cambrian fossil locations worldwide exhibiting exquisite preservation of rarely preserved, non-mineralized soft tissue, comparable to the fossils of the Burgess Shale. They take their name from Maotianshan Hill (, Literal meaning: Hat Sky Mountain) in Chengjiang County, Yunnan Province, China. The most famous assemblage of organisms are referred to as the Chengjiang biota for the multiple scattered fossil sites in Chengjiang. The age of the Chengjiang Lagerstätte is locally termed Qiongzhusian, a stage correlated to the late Atdabanian Stage in Siberian sequences of the middle of the Early Cambrian. The shales date to ≤. The shales also contain the slightly younger Guanshan biota from Malong District in Yun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagerstätte
A Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus delaying the decomposition of both gross and fine biological features until long after a durable impression was created in the surrounding matrix. ''Lagerstätten'' span geological time from the Neoproterozoic era to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Silurian Waukesha Biota, the Devonian Hunsrück Slates and Gogo Formation, the Carboniferous Mazon Creek, the Jurassic Posidonia Shale and Solnhofen Limestone, the Cretaceous Yixian, Santana, and Agua Nueva formations, the Eocene Green River Formation, the Miocene Foulden Maar and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carapace
A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron. Crustaceans In crustaceans, the carapace functions as a protective cover over the cephalothorax (i.e., the fused head and thorax, as distinct from the abdomen behind). Where it projects forward beyond the eyes, this projection is called a rostrum. The carapace is calcified to varying degrees in different crustaceans. Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera, ostracods, and isopods, but isopods only have a developed "cephalic shield" carapace covering the head. Arachnids In arachnids, the carapace is formed by the fusion of prosomal tergites into a single plate which carries the eyes, ocularium, ozopores (a pair of openings of the scent gland of Opilione ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostracod
Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typically around in size, but varying from in the case of '' Gigantocypris''. Their bodies are flattened from side to side and protected by a bivalve-like, chitinous or calcareous valve or "shell". The hinge of the two valves is in the upper (dorsal) region of the body. Ostracods are grouped together based on gross morphology. While early work indicated the group may not be monophyletic and early molecular phylogeny was ambiguous on this front, recent combined analyses of molecular and morphological data found support for monophyly in analyses with broadest taxon sampling. Ecologically, marine ostracods can be part of the zooplankton or (most commonly) are part of the benthos, living on or inside the upper layer of the sea floor. While Myod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans ( Remipedia, Cephalocarida, Branchiopoda) are more closely related to insects and the other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese spider crab with a leg span of up to and a mass of . Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Appendage
Great appendages are claw-like appendages which attach to the heads of the "great appendage arthropods", a name usually refers to Megacheira, a class of extinct arthropod characterized by a pair of "short-great appendages" bearing in front of the animal's head. In general, megacheiran's great appendage have 6 segments, with the two proximal segments forming a peduncle and the four finger-like distal segments forming a claw, both connected by an elbow joint. Great appendages have been interpreted as raptorial limbs involved in predation, with those of some genera such as ''Yohoia'' being structurally comparable to the raptorial maxillipeds of mantis shrimp. The great appendages of leanchoilid megacheirans such as ''Leanchoilia'' and ''Yawunik'' have elongated flagella, suggesting a sensory role alongside predatory function. Radiodont's frontal appendages have controversial relationships to those of the megacheirans. They have been suggested to be homologous with the antennule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Arthropod Genera
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] |
