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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 ** List ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Chengjiang Biota Species By Phylum
This is a list of fossils found at Maotianshan Shales, whose most famous assemblage of organisms are referred to as the Chengjiang biota. Phylum Arthropod, Arthropoda 80 species, not counting Dinocarida, Nektaspida and Trilobita * ''Acanthomeridion, Acanthomeridion serratum'' * ''Alalcomenaeus'' * ''Almenia, Almenia spinosa'' * ''Apiocephalus, Apiocephalus elegans'' * ''Branchiocaris, Branchiocaris yunnanensis'' * ''Canadaspis, Canadaspis laevigata'' * ''Chengjiangocaris, Chengjiangocaris longiformis'' * ''Chuandianella, Chuandianella ovata'' * ''Cindarella, Cindarella eucalla'' * ''Clypecaris, Clypecaris pteroidea'' * ''Combinivalvula, Combinivalvula chengjiangensis'' * ''Comptaluta inflata'' * ''Comptaluta leshanensis'' * ''Cyathocepalus, Cyathocepalus bispinosus'' * ''Dianchia, Dianchia mirabilis'' * ''Diplopyge'' ** ''D. forcipatus'' ** ''D. minutus'' * ''Dongshanocaris, Dongshanocaris foliiformis'' * ''Ercaia, Ercaia minuscula'' * ''Ercaicunia, Ercaicunia multinodos ... [...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. Radiodonta, Radiodont's frontal appendages have controversial relationships to those of the megacheirans. They have been suggested to be Homology (biology), ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megacheira
Megacheira ("great hands") is an extinct class of predatory arthropods that possessed a pair of great appendages, hence the class name as well as the common name "great appendage arthropods". Their taxonomic position is controversial, with studies either considering them stem-group euarthropods, or stem-group chelicerates. Most of them were found in marine environments throughout the world from the lower to middle Cambrian. Megacheirans were important components of several faunas, including the Burgess, Wheeler and Maotianshan Shales Lagerstatten. Homology of great appendages The homology between megacheiran great appendages and cephalic appendages of other arthropods had been discussed for decades. There is controversy over whether they are homologous to both dinocaridid (radiodonts and gilled lobopodians) frontal appendages, the frontalmost appendages of ''Isoxys'' and chelicerates' chelicerae. Based on neuroanatomical evidences, many studies support their homology to ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forfexicaris Valida
''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 appendages, which closely resemble those of ''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 ...''. References Prehistoric arthropod genera Cambrian arthropods Maotianshan shales fossils {{paleo-arthropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nekton
Nekton or necton (from the ) refers to the actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms that were carried along by the current, the plankton. As a guideline, nektonic organisms have a high Reynolds number (greater than 1000) and planktonic organisms a low one (less than 10). However, some organisms can begin life as plankton and transition to nekton later on in life, sometimes making distinction difficult when attempting to classify certain plankton-to-nekton species as one or the other. For this reason, some biologists choose not to use this term. History The term was first proposed and used by the German biologist Ernst Haeckel in 1891 in his article ''Plankton-Studien'' where he contrasted it with plankton, the aggregate of passively floating, drifting, or somewhat motile organisms present in a body of water, primarily t ... [...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. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chengjiang Biota
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 Yunnan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Explosion
The Cambrian explosion, Cambrian radiation, Cambrian diversification, or the Biological Big Bang refers to an interval of time approximately in the Cambrian Period when practically all major animal phyla started appearing in the fossil record. It lasted for about 13 – 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well. Before early Cambrian diversification, most organisms were relatively simple, composed of individual cells, or small multicellular organisms, occasionally organized into colonies. As the rate of diversification subsequently accelerated, the variety of life became much more complex, and began to resemble that of today. Almost all present-day animal phyla appeared during this period, including the earliest chordates. A 2019 paper suggests that the timing should be expanded back to include the late Ediacaran, rather than just the n ... [...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] |
Mandibulata
Mandibulata, termed "mandibulates", is a clade of arthropods that comprises the extant subphyla Myriapoda (millipedes and others), Crustacea and Hexapoda (insects and others). Mandibulata is currently believed to be the sister group of the clade Arachnomorpha, which comprises the rest of arthropods (Chelicerata and Trilobita). The mandibulates constitute the largest and most varied arthropod group. The name "Mandibulata" refers to the mandibles or jaws, which are the characterizing feature of its member arthropods. Molecular phylogenetic studies suggest that the living arthropods are related as shown in the cladogram below. Crustaceans do not form a monophyletic group as insects and other hexapods have evolved from within them. See also *Atelocerata *Marrellomorpha *Myriochelata *Pancrustacea *Crustaceomorpha Crustaceomorpha is a proposed clade of arthropods that includes crustaceans and numerous extinct groups. Synapomorphies for the clade are that the larval antenna is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fortiforceps
''Fortiforceps'' is an extinct genus of Cambrian megacheiran arthropod known from the Chengjiang biota of Yunnan, China. It was originally described by Hou and Bergström in 1997,X. Hou and J. Bergström. 1997Arthropods of the Lower Cambrian Chengjiang fauna, southwest China Fossils & Strata 45:1-116 and redescribed in 2020. It was relatively small, at or less in length. The head has a large pair of stalked eyes, a pair of frontal projections, as well as a pair of great appendages, like other megacheirans, along with two other cephalic appendages. The trunk has either 20 or 22 segments, depending on the specimen. These segments have pronounced blade-like spines on their upper-outer edge. Each of the trunk segments (aside from the last, typically 20th segment) are associated with pairs of biramous The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acta Palaeontologica Polonica
''Acta Palaeontologica Polonica'' is a quarterly peer-reviewed open access scientific journal of paleontology and paleobiology. It was established by Roman Kozłowski in 1956. It is published by the Institute of Paleobiology of the Polish Academy of Sciences and edited by Richard L. Cifelli and Jarosław Stolarski. Abstracting and indexing ''Acta Palaeontologica Polonica'' is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2010 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 1.949, ranking it 11th out of 48 journals in the category "Paleontology". References External links * Institute of Paleobiology Paleontology journals Publications established in 1956 Polish Academy of Sciences academic journals Open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
