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Goticaris
''Goticaris'' is an extinct genus of enigmatic Cambrian arthropod consisting of the single species ''Goticaris longispinosa'', known from the Orsten lagerstätten in southern Sweden. It appears to have several apomorphic features, notably including a large compound eye. Etymology The genus name ''Goticaris'' is in reference to the Gotes, a tribe which inhabited southern Sweden in the “Dark Ages”. The species name ''longispinosa'' refers to the long caudal spine. Description Originally, ''Goticaris'' was estimated to be approximately long, but new specimens helped infer the new size at long. The head of ''Goticaris'' has an unusual anterior projection of the head that bears a single large and what are possibly two smaller stalked compound eyes. There are four pairs of appendages on its head. The first pair of appendages are treated as antennae, and the other appendages on head are biramous. The mouth opens on the ventral surface in front of the second pair of appenda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambropachycope
''Cambropachycope'' is an extinct genus of enigmatic Cambrian arthropod that includes the single species ''Cambropachycope clarksoni'', known from the Orsten lagerstätten in southern Sweden. It appears to have several apomorphic features, notably including a single large compound eye. Etymology The genus name ''Cambropachycope'' refers to the large unilobed eye, alongside it originating from the Cambrian period. The specific name ''clarksoni'' honours E. N. K. Clarkson. Description Cambropachycope diagrammatic reconstruction.png, Diagram of ''Cambropachycope'' Cambropachycopidae size comparison.svg, Size diagram, compared to '' Goticaris'' Originally, ''Cambropachycope'' was determined to be approximately long based on the specimens known up to that time, however, the discovery of new specimens helped infer the new size to be approximately long (3 mm head and abdomen, and 1 mm telson). The head of ''Cambropachycope'' has an unusual anterior projection that bears a sing ... [...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] |
Arthropod
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metamerism (biology), metameric) Segmentation (biology), segments, and paired jointed appendages. 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. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior Organ (anatomy), organs. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. They have ladder-like nervous systems, with paired Anatomical terms of location#Dorsal and ventral, ventral Ventral nerve cord, nerve cord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Arthropod 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 Arthropods
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, Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new Convergent boundary, convergent plate boundaries and Volcanic arc, 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, life on Earth; prior to the Period, the majority of living organisms were small, Unicellular organism, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bythotrephes Longimanus
''Bythotrephes longimanus'' (also ''Bythotrephes cederstroemi''), or the spiny water flea, is a planktonic crustacean less than long. It is native to fresh waters of Northern Europe and Asia, but has been accidentally introduced and widely distributed in the Great Lakes area of North America since the 1980s.''Bythotrephes longimanus'' USGS NAS – Nonindigenous Aquatic Species ''Bythotrephes'' is typified by a long abdominal spine with several barbs which protect it from predators. Description and taxonomy ''Bythotrephes longimanus'' is a cladoceran crustacean (water flea) recognizable with its straight tail spine averaging about 70% of its length. Adult individuals have one to three pairs of barbs on the ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplostraca
The Diplostraca or Cladocera, commonly known as water fleas, is a superorder of small, mostly freshwater crustaceans, most of which feed on microscopic chunks of organic matter, though some forms are predatory. Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, though several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandibulata
The clade Mandibulata constitutes one of the major subdivisions of the phylum Arthropoda, alongside Chelicerata. Mandibulates include the crustaceans, myriapods (centipedes and millipedes, among others), and all true insects. The name "Mandibulata" refers to the mandibles, a modified pair of limbs used in food processing, the presence of which are characteristic of most members of the group. The mandibulates are divided between the extant groups Myriapoda (millipedes and centipedes, among others) and Pancrustacea (including crustaceans and hexapods, the latter group containing insects). Molecular phylogenetic studies suggest that the living arthropods are related as shown in the cladogram below. Crustaceans do not form a monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martinssonia
''Martinssonia'' is an extinct genus of Cambrian arthropod from the Orsten Lagerstätte. Description ''Martinssonia'' is a small (roughly 1.5 mm long) arthropod, with eight pairs of appendages and ten segments including the eyeless head. It has a pair of antennae, twelve biramous appendages on its head and front two body segments and a final pair of uniramous appendages on its third segment. ''Martinssonia'' also seems to have a pleotelson The telson () is the hindmost division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on account of ..., similar to modern crustacean larvae. Ecology ''Martinssonia'' was presumably a benthic detritivore, stirring up food particles from the seafloor. Etymology ''Martinssonia'' is named for Anders Martinsson, a former Professor of Palaeobiology at Uppsala University in Sweden. The specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henningsmoenicaris
''Henningsmoenicaris'' is an extinct genus of Cambrian arthropods from the Orsten of Sweden. It was formerly named ''Henningsmoenia'', however this name was preoccupied by an ostracod Ostracods, or ostracodes, are a Class (biology), class of the crustacean, Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant taxon, extant) have been identified,Brandão, S.N.; Antoni ..., therefore it was renamed. Its genus name translates to "Henningsmoen's shrimp" after G. Henningsmoen. The genus contains a single species, ''Henningsmoenicaris scutula'', with the specific name, ''scutula'' referencing the large, bowl-shaped carapace. Morphology ''Henningsmoenicaris'' unusually had an almost 360° field of vision, with two extremely long stalked eyes facing in almost all directions at once, even ''inwards'' to give depth perception to the opposite eye. Aside from this, it is a relatively "ordinary" Orsten arthropod with a large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tergum
A ''tergum'' (Latin for "the back"; : ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ... segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'margin'. A given tergum may be divided into hardened plates or sclerites commonly referred to as tergites. In a thoracic segment, for example, the tergum may be divided into an anterior notum and a posterior scutellum. Lateral extensions of a tergite are known as paranota (Greek for "alongside the back") or ''carinae'' (Latin for "keel"), exemplified by the flat-backed millipedes of the order Polydesmida. Kinorhynchs have tergal and sternal plates too, though seemingly not homologous with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancrustacea
Pancrustacea is the clade that comprises all crustaceans and all hexapods (insects and relatives). This grouping is contrary to the Atelocerata hypothesis, in which Hexapoda and Myriapoda are sister taxa, and Crustacea are only more distantly related. As of 2010, the Pancrustacea taxon was considered well accepted, with most studies recovering Hexapoda within Crustacea. The clade has also been called Tetraconata, referring to having a four-part cone in the ommatidium. The term "Tetraconata" is preferred by some scientists in order to avoid confusion with the use of "pan-" to indicate a clade that includes a crown group and all of its stem group representatives. Molecular studies A monophyletic Pancrustacea has been supported by several molecular studies, in most of which the subphylum Crustacea is paraphyletic with regard to hexapods (that is, that hexapods, including insects, are derived from crustacean ancestors). This means that within Pancrustacea, only some members are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
