|
Arachnomorpha (beetle)
Arachnomorpha is a proposed subdivision or clade of Arthropoda, comprising the group formed by the trilobites and their close relatives (Artiopoda), Megacheira (which may be paraphyletic) and chelicerates. Under this proposed classification scheme, Arachnomorpha is considered the sister group to Mandibulata (including insects, crustaceans and myriapods). The arachnomorph concept has been challenged by suggestions that the artiopods are more closely related to mandibulates, forming the clade Antennulata instead. There is no consensus as to assigning Arachnomorpha a formal Linnean rank. Classification Arachnomorpha Lameere, 1890 Arachnata Paulus, 1979, = Palaeopoda Packard, 1903*†'' Nettapezoura'' *†'' Dicranocaris'' *†Trilobita Walch, 1771 *†Megacheira Hou & Bergstrom, 1997 *†Strabopida Hou & Bergström, 1997 *†Aglaspida Walcott, 1911 *†Cheloniellida Broili, 1932 *Chelicerata Heymons 1901 **Family † Sanctacarididae Legg & Pates, 2017 **Class Pycnogonida Latr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellacartwrightia
''Bellacartwrightia'' is a relatively uncommon genus of phacopid trilobite, found in the mid-Devonian Hamilton Group of New York state, mainly in strata exposed near Lake Erie just west of Buffalo Buffalo most commonly refers to: * True buffalo or Bubalina, a subtribe of wild cattle, including most "Old World" buffalo, such as water buffalo * Bison, a genus of wild cattle, including the American buffalo * Buffalo, New York, a city in the n .... This trilobite is usually about 1.5" to 2" long. A very similar trilobite from the Devonian of Morocco is still sold as ''Metacanthina'', but considerable research is still being done on Moroccan trilobites. References *Brett, Carlton, et al., ''Trilobites of New York''. Rochester: Rochester University Press, 2003. Devonian trilobites of North America Acastidae Fossils of the United States Phacopida genera {{Phacopida-stub ... [...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] |
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] |
Offacolidae
Offacolidae is a family of basal euchelicerate arthropods from the Ordovician and Silurian of Europe, Morocco and North America. The family is united by several features, including paddle-like sixth post-cheliceral appendages, elongated chelicerae, and reduced first tergites, although these are apparently not unique to the clade, but instead euchelicerate or wider synapomorphies, therefore making the clade paraphyletic. Alongside this, ''Offacolus'' may be more basal than the rest of the clade, as its seventh exopod pair is unreduced and it has a bipartite telson 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 (biology), segment of the arthropod body, or an additional division that is not a true segm ..., among other features. They share with most other euchelicerates a wide carapace, which has led to them being placed in the paraphyletic “ Synziphosurina” for a long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euchelicerata
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 Segmentation (biology), segmented bodies with jointed limbs, all cove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pycnogonida
Sea spiders are marine arthropods of the class Pycnogonida, hence they are also called pycnogonids (; named after ''Pycnogonum'', the type genus; with the suffix '). The class includes the only now-living order Pantopoda ( ‘all feet’), alongside a few fossil species which could trace back to the early or mid Paleozoic. They are cosmopolitan, found in oceans around the world. The over 1,300 known species have leg spans ranging from to over . Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters. Despite their name and brief resemblance, "sea spiders" are not spiders, nor even arachnids. While some literature around the 2000s suggests they may be a sister group to all other living arthropods, their traditional classification as a member of chelicerates alongside horseshoe crabs and arachnids has regained wide support in subsequent studies. Morphology Many sea spiders are recognised ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sanctacarididae
Habeliida is an order of extinct arthropods that existed during the middle Cambrian. It is divided into two families, Habeliidae (monotypic, containing only ''Habelia''), and Sanctacarididae (containing ''Sanctacaris'', '' Utahcaris'' and ''Wisangocaris''). They are thought to have been durophagous, with robust gnathobases (spined basal sections of limbs) used to shred hard-shelled organisms. Remains of trilobites have been found as stomach contents in ''Wisangocaris''. '' Messorocaris'' has been suggested to be part of the order in some studies, but this is uncertain. They are suggested to be stem-group chelicerates, though they lack the chelicerae The chelicerae () are the arthropod mouthparts, mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated ... present in true chelicerates. References Chelicerate orders Prehistoric chel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheloniellida
Cheloniellida is a taxon (usually referred to as an order) of extinct Paleozoic arthropods. As of 2018,Wendruff, Andrew James, et al. "New cheloniellid arthropod with large raptorial appendages from the Silurian of Wisconsin, USA." BioRxiv (2018): 407379/ref> 7 monotypic genera of cheloniellids had been formally described, whose fossils are found in marine strata ranging from Ordovician to Devonian in age. Cheloniellida has a controversial phylogenetic position, with previous studies associated it as either a member or relative of various fossil and extant arthropod taxa. It was later accepted as a member of Vicissicaudata within Artiopoda. Morphology The flattened, ovoid body of cheloniellid comprises an eye-bearing cephalon (head) and segmented trunk region, dorsally divided by a series of tergites (dorsal exoskeleton). The cephalon could be divided into procephalon and gnathocephalon. Compared to other members of Artiopoda, the head shield (dorsal exoskeleton of cephalon) of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aglaspida
Aglaspidida is an extinct order of marine arthropods known from fossils spanning the Middle Cambrian to the Upper Ordovician. Initially considered chelicerates, modern anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within this group, and that they lie instead within the Artiopoda, thus placing them closer to the trilobites, being placed in the artiopod subgroup Vicissicaudata. With 38 known valid species as of 2017, they represent one of the most diverse groups of early Paleozoic arthropods, after trilobites.Lerosey-Aubril, R., Ortega-Hernández, J., Van Roy, P., Zhu, X., (2017)The Aglaspidida: a poorly-known, yet important order of early Palaeozoic arthropods ''International Workshop on Evolution of Cambrian Arthropods - Taxonomy, Ontogeny and Phylogeny''. 1-6 Sep. 2017, Xian, China. Aglaspidid fossils are found in North America (United States and Canada), Europe, Australia, and China. Description The exoskeletons of aglaspidids have frequently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabopida
Strabopidae is the only Family (biology), family of the order Strabopida, an extinct group of arthropods known from the Cambrian period. The order Strabopida contains three valid genera and one doubtful, ''Khankaspis'', ''Paleomerus'', ''Parapaleomerus'' and ''Strabops'', all assigned in the family Strabopidae. Previously, it also contained the genera ''Caryon'', ''Lemoneites'' and ''Neostrabops'', but after a study, they were reassigned as a trilobite, a Glyptocystitida, glyptocystitid echinoderm and a cheloniellid arthropod, respectively. Paleomeridae was also previously included as a family, but after the discovery of a fourth ''Paleomerus'' Biological specimen, specimen and its study, Paleomeridae was synonymized into Strabopidae. Although often suggested to be closely related to Aglaspidida, aglaspidids due to their similar morphology, their exact phylogenetic placement is uncertain due to the poor preservation of all known strabopids. A 2013 attempt to place them in a phylo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
