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Planaterga
Planaterga is a clade of prosomapod euchelicerates including several synziphosurid genera (mainly bunodids and pseudoniscids) and the group Dekatriata (which in turn includes arachnids, chasmataspidids and eurypterid Eurypterids, often informally called sea scorpions, are a group of extinct marine arthropods that form the Order (biology), order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period, 467.3 Myr, mil ...s). Planaterga is defined by the opisthosoma with tergites broadest at third or fourth and lacking enlarged axial nodes, carapace (prosomal dorsal shield) with reduced genal spines, as well as somite VII (first opisthosomal segment) with reduced appendages and microtergite. References Middle Ordovician first appearances {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pasternakevia
''Pasternakevia'' is a genus of synziphosurine, a paraphyletic group of fossil chelicerate Arthropod, arthropods. ''Pasternakevia'' was regarded as part of the clade Planaterga. Fossils of the single and type species, ''P. podolica'', have been discovered in Deposition (geology), deposits of the Silurian Period (geology), period in Podolia, Ukraine. The prosoma of ''Pasternakevia'' covered by a smooth, semicircular carapace with rounded genal cornua (posterolateral corner of carapace). Within the 10-segmented opisthosoma, tergite of the first segment is reduced and usually hidden under the preceding carapace, while the second one is significantly arched and well-developed. All but the first tergite possess well-developed pleurae (lateral extension). A complete telson is yet to be discovered. References Synziphosurina Planaterga Silurian first appearances Silurian arthropods Fossils of Ukraine Fossil taxa described in 1987 {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prosomapoda
Prosomapoda is a clade of Chelicerata, euchelicerates including the groups Xiphosura (horseshoe crabs) and Planaterga (a group comprising Bunodidae, bunodids, Pseudoniscidae, pseudoniscids, Chasmataspidida, chasmataspidids, Eurypterida, eurypterids and Arachnida, arachnids), as well as several basal Synziphosurina, synziphosurid genera. The clade is defined by the lack of exopods (outer branches) of prosomal appendage II-V in the adult instar, where in contrast the exopods of appendage II-V are well-developed in the non-prosomapod euchelicerates ''Offacolus'' and ''Dibasterium''. References Prosomapoda, Middle Ordovician first appearances {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bunodidae
Bunodidae is an extinct family of synziphosurine chelicerates that lived in the Silurian. Bunodidae is classified inside the clade Planaterga alongside Pseudoniscidae and Dekatriata ( chasmataspidids, eurypterids and arachnids). Bunodidae is composed by two genera, ''Bunodes'' (the type genus) and ''Limuloides ''Limuloides'' is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. ''Limuloides'' was regarded as part of the clade Planaterga. Fossils of the genus have been discovered in deposits of the Silurian period in the U ...''. References Synziphosurina Planaterga Silurian first appearances Silurian arthropods Silurian extinctions Prehistoric arthropod families {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limuloides
''Limuloides'' is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. ''Limuloides'' was regarded as part of the clade Planaterga. Fossils of the genus have been discovered in deposits of the Silurian period in the United Kingdom and potentially in the United States. ''Limuloides'' is one of the two genera of the family Bunodidae, the other being the type genus '' Bunodes''. ''Limuloides'' is characterized by a carapace with radiated ridges and serrated lateral regions, and an opisthosoma with rows of nodes. ''Limuloides'' was once thought to have lateral compound eye A compound eye is a Eye, visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidium, ommatidia, which are tiny independent photoreception units that consist of a cornea, lens (anatomy), lens, and p ...s on its carapace, but later investigation did not find any evidence of it. References Synziphosurina Planaterga Silurian first a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bembicosoma
''Bembicosoma'' is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. ''Bembicosoma'' was regarded as part of the clade Planaterga. Fossils of the single and type species, ''B. pomphicus'', have been discovered in Deposition (geology), deposits of the Silurian Period (geology), period in the Pentland Hills, Scotland (in the United Kingdom). ''Bembicosoma'' had been tentatively assigned as an eurypterid (sea scorpion) before its synziphosurine affinities revealed. The prosoma of ''Bembicosoma'' covered by a short, semicircular carapace without evidence of ophthalmic ridges. Within the 10-segmented opisthosoma, the first segment is nearly as wide as the carapace but reduced in length while the second segment is the largest. The dorsal surfaces of both prosoma and opisthosoma covered by numerous tubercules. References Synziphosurina Planaterga Silurian first appearances Silurian arthropods Fossils of Scotland Fossil taxa described in 1899 {{C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoniscidae
Pseudoniscidae is an extinct family of synziphosurine chelicerates that lived in the Silurian. Pseudoniscidae is classified inside the clade Planaterga, alongside Bunodidae and Dekatriata ( chasmataspidids, eurypterids and arachnids). Pseudoniscidae is composed by two genera, '' Cyamocephalus'' and '' Pseudoniscus'' (the type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...). References Synziphosurina Planaterga Silurian first appearances Silurian arthropods Silurian extinctions Prehistoric arthropod families {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bunaia
''Bunaia'' is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. ''Bunaia'' was tentatively placed as part of the clade Planaterga, however a 2024 study found it to be within Offacolidae instead. The genus contains at least one species: ''Bunaia woodwardi'' from the Silurian period in Svalbard, Norway and the Bertie Group of Ontario Description Initially, the species was known only from poorly preserved specimens composed of semicircular carapace, fragments of opisthosoma and disarticulated telson. The aforementioned 2024 study described additional specimens, which revealed "a pair of elongated chelicerae in the prosoma, followed posteriorly by five pairs of biramous appendages, a first pre-abdomen somite bearing a pair of paddle-like uniramous appendages ( exopods) and a ventral pretelsonic process." Taxonomy The placement of ''"Bunaia" heintzi'' (known only by a single carapace from the Silurian period in the United States The Unite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelicerate
The subphylum Chelicerata (from Neo-Latin, , ) constitutes one of the major subdivisions of the phylum Arthropoda. Chelicerates include the sea spiders, horseshoe crabs, and arachnids (including harvestmen, scorpions, spiders, solifuges, ticks, and mites, among many others), as well as a number of extinct lineages, such as the eurypterids (sea scorpions) and chasmataspidids. Chelicerata split from Mandibulata by the mid-Cambrian, as evidenced by stem-group chelicerates like Habeliida and '' Mollisonia'' present by this time. The surviving marine species include the four species of xiphosurans (horseshoe crabs), and possibly the 1,300 species of pycnogonids (sea spiders), if the latter are indeed chelicerates. On the other hand, there are over 77,000 well-identified species of air-breathing chelicerates, and there may be about 500,000 unidentified species. Like all arthropods, chelicerates have segmented bodies with jointed limbs, all covered in a cuticle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypterid
Eurypterids, often informally called sea scorpions, are a group of extinct marine 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 Permi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arachnid
Arachnids are arthropods in the Class (biology), class Arachnida () of the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, opiliones, harvestmen, Solifugae, camel spiders, Amblypygi, whip spiders and Uropygi, vinegaroons. Adult arachnids have eight Arthropod leg, legs attached to the cephalothorax. In some species the frontmost pair of legs has converted to a sensory function, while in others, different appendages can grow large enough to take on the appearance of extra pairs of legs. Almost all Extant taxon, extant arachnids are terrestrial animal, terrestrial, living mainly on land. However, some inhabit freshwater environments and, with the exception of the pelagic zone, marine environments as well. They comprise over 110,000 named species, of which 51,000 are species of spiders. The term is derived from the Ancient Greek, Greek word (''aráchnē'', 'spider'), from the myth of the hubristic human weaver Arachne, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mite
Mites are small arachnids (eight-legged arthropods) of two large orders, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as each other's closest relative within Arachnida, rendering the group invalid as a clade. Most mites are tiny, less than in length, and have a simple, unsegmented body plan. The small size of most species makes them easily overlooked; some species live in water, many live in soil as decomposers, others live on plants, sometimes creating galls, while others are Predation, predators or Parasitism, parasites. This last type includes the commercially destructive ''Varroa'' parasite of honey bees, as well as scabies mites of humans. Most species are harmless to humans, but a few are associated with allergies or may transmit diseases. The scientific discipline devoted to the study of mites is called acarology. Evolution and taxonomy Mites are not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
