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Megarachne
''Megarachne'' is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of ''Megarachne'' have been discovered in deposits of Late Carboniferous age, from the Gzhelian stage, in San Luis, Argentina. The fossils of the single and type species ''M. servinei'' have been recovered from deposits that had once been a freshwater environment. The generic name, composed of the Ancient Greek μέγας (''megas'') meaning "great" and Ancient Greek ἀράχνη (''arachne'') meaning "spider", translates to "great spider", because the fossil was misidentified as a large prehistoric spider. With a body length of , ''Megarachne'' was a medium-sized eurypterid. If the original identification as a spider had been correct, ''Megarachne'' would have been the largest known spider to have ever lived. Eurypterids such as ''Megarachne'' are often called "sea scorpions", but the strata in which ''Megarachne'' has been found indicates that it dwelled in freshwater and not in marine e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycteroptidae
Mycteroptidae are a family of eurypterids, a group of extinct chelicerate arthropods commonly known as "sea scorpions". The family is one of three families contained in the superfamily Mycteropoidea (along with Hibbertopteridae and Drepanopteridae), which in turn is one of four superfamilies classified as part of the suborder Stylonurina. Mycteroptids were sweep-feeding eurypterids known from the Late Carboniferous to the Late Permian. Description Mycteroptids were medium-sized to fairly large mycteropoids with parabolic prosoma and a hastate telson with paired ventral keels. They had a culticular ornament of scales or mucrones and unlike the hibbertopterids, appendage IV was non-spiniferous. The first and second opisthosomal tergites were strongly developed and elongated. The heads of mycteroptids were subtrapezoid in shape with small compound eyes. 1955. Merostomata. ''Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata'', P39. Mycteroptids only use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycteropoidea
Mycteropoidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina. Mycteropoids have been recovered from Europe, Russia, South America and South Africa. Mycteropoid specimens are often fragmentary, making it difficult to establish relationships between the included taxa. Only two mycteropoid taxa are known from reasonable complete remains, '' Hibbertopterus scouleri'' and ''H. wittebergensis''. Mycteropoids were large bizarre Eurypterids found from the Early Silurian to the end of the Permian period. They were sweep feeders, inhabiting freshwater swamps and rivers, feeding by raking through the soft sediment with blades on their anterior appendages to capture small invertebrates. Their morphology was so unusual that they have been thought to be an order separate to Eurypterida. Recent work however confirms them to be derived members o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous'' means "coal-bearing", from the Latin '' carbō'' ("coal") and '' ferō'' ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial animal life was well established by the Carboniferous Period. Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, became pentadactylous in and diversified during the Carboniferous, including early amphibian line ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hibbertopterus
''Hibbertopterus'' is a genus of eurypterid, a group of extinct aquatic arthropods. Fossils of ''Hibbertopterus'' have been discovered in deposits ranging from the Devonian period in Belgium, Scotland and the United States to the Carboniferous period in Scotland, Ireland, the Czech Republic and South Africa. The type species, ''H. scouleri'', was first named as a species of the significantly different ''Eurypterus'' by Samuel Hibbert in 1836. The generic name ''Hibbertopterus'', coined more than a century later, combines his name and the Greek word πτερόν (''pteron'') meaning "wing". ''Hibbertopterus'' was the largest eurypterid within the stylonurine suborder, with the largest fossil specimens suggesting that ''H. scouleri'' could reach lengths around 180–200 centimetres (5.9–6.6 ft). Though this is significantly smaller than the largest eurypterid overall, ''Jaekelopterus'', which could reach lengths of around , ''Hibbertopterus'' is likely to have been the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycterops
''Mycterops'' is a genus of prehistoric eurypterid of the family Mycteroptidae. ''Mycterops'' lived during the Carboniferous period in Europe and North America. Description Mycteroptids were medium-sized to fairly large. Their outer surface had numerous scales and reticulate ornamentation. Their first and possibly second tergites (dorsal surfaces of the abdominal sections) were strongly developed. Their legs resembled those of '' Stylonurus''. The prosoma (head) was subtrapezoid, with small compound eyes. 1955. Merostomata. ''Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata'', P39. Classification The three genera included in the ''Mycteroptidae'' - ''Mycterops'', '' Woodwardopterus'', and ''Megarachne'' - might represent different ontogenetic stages of each other based on the sizes of the referred specimens and the patterns of mucronation. This would sink the genera ''Woodwardopterus'' and ''Megarachne'' into ''Mycterops''. ''Mycterops whitei'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woodwardopterus
''Woodwardopterus'' is a genus of prehistoric eurypterid, or sea scorpion, classified as part of the family Mycteroptidae. The genus contains one confirmed species, ''W. scabrosus'', from the Carboniferous of Glencartholm, Scotland. Originally classified as ''Eurypterus scabrosus'', it was later found to be generically distinct and placed as a member of the family Mycteroptidae. Later in 2005, was assigned to its own genus, and linked to a new own family, Woodwardopteridae inside Mycteropoidea, probably as a sister taxon of ''Megarachne''. W. scarabrosus had carapace length about and estimated total length about . A possible second species, ?''W. freemanorum'' was named in 2021 and comes from the Changhsingian (Late Permian) beds of the Baralaba Coal Measures, Bowen Basin, central Queensland, Australia. This possible second species is important due to be the geologically youngest eurypterid discovered (at least 11 Ma younger than any previously known relative), showing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypterid
Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the Order (biology), order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 Myr, million years ago. The group is likely to have appeared first either during the Early Ordovician or Late Cambrian period. With approximately 250 species, the Eurypterida is the most diverse Paleozoic Chelicerata, chelicerate order. Following their appearance during the Ordovician, eurypterids became major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described. The Silurian genus ''Eurypterus'' accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event. They declined in numbers and diversity until becoming extinct during the Permian–Tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cuticle
A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structure, function, and chemical composition. Human anatomy In human anatomy, "cuticle" can refer to several structures, but it is used in general parlance, and even by medical professionals, to refer to the thickened layer of skin surrounding fingernails and toenails (the eponychium), and to refer to the superficial layer of overlapping cells covering the hair shaft ( cuticula pili), consisting of dead cells, that locks the hair into its follicle. It can also be used as a synonym for the epidermis, the outer layer of skin. Cuticle of invertebrates In zoology, the invertebrate cuticle or cuticula is a multi-layered structure outside the epidermis of many invertebrates, notably roundworms and arthropods, in which it forms an exoskeleton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Ornament
A biological ornament is a characteristic of an animal that appears to serve a decorative function rather than a utilitarian function. Many are secondary sexual characteristics, and others appear on young birds during the period when they are dependent on being fed by their parents. Ornaments are used in displays to attract mates, which may lead to the evolutionary process known as sexual selection. An animal may shake, lengthen, or spread out its ornament in order to get the attention of the opposite sex, which will in turn choose the most attractive one with which to mate. Ornaments are most often observed in males, and choosing an extravagantly ornamented male benefits females as the genes that produce the ornament will be passed on to her offspring, increasing their own reproductive fitness. As Ronald Fisher noted, the male offspring will inherit the ornament while the female offspring will inherit the preference for said ornament, which can lead to a positive feedback loop kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma (cephalothorax). It is a distinctive feature of the subphylum Chelicerata (arachnids, horseshoe crabs and others). Although it is similar in most respects to an abdomen (and is often referred to as such), the opisthosoma is differentiated by its inclusion of the respiratory organs (book lungs or book gills) and the heart. Segments The number of segments and appendages on the opisthosoma vary. Scorpions have 13, but the first is only seen during its embryological development. Other arachnids have fewer; harvestmen, for instance, have only ten. In general, appendages are absent or reduced, although in horseshoe crabs they persist as large plate-like limbs, called opercula or branchiophores, bearing the book gills, and that function in locomotion and gas exchange. In most chelicerates the opisthosomal limbs are greatly reduced and persist only as specialized structures, such as the silk-producing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carapace
A carapace is a Dorsum (biology), 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 (anatomy), rostrum. The carapace is Calcification, calcified to varying degrees in different crustaceans. Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera, ostracods, and Isopoda, 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 (animal anatomy), plate which carries the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquatic Ecosystem
An aquatic ecosystem is an ecosystem formed by surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic (slow moving water, including pools, ponds, and lakes); lotic (faster moving water, for example streams and rivers); and wetlands (areas where the soil is saturated or inundated for at least part of the time). Types Marine ecosystems Marine coastal ecosystem Marine surface ecosystem Freshwater ecosystems Lentic ecosystem (lakes) Lotic ecosystem (rivers) Wetlands Functions Aquatic ecosystems perform many important environmental functions. For example, they recycle nutrients, purify water, attenuate floods, recharge ground water and provide habitats for wildlife. Aquatic ecosystems are also used for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
