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Parioscorpio
''Parioscorpio'' is an extinct genus of arthropod containing the species ''P. venator'' known from the Silurian-aged Waukesha Biota of the Brandon Bridge Formation near Waukesha, Wisconsin. Taxonomy The fossils were originally discovered in 1985, tentatively identified as a branchiopod or remipede crustacean but were neglected for decades. In 2016, some of the fossils now assigned to ''Parioscorpio'' were given the name ''Latromirus'' and were assigned to an extinct group of early Paleozoic arthropods known as cheloniellids in a Ph.D dissertation, but the name was never published in a peer-reviewed journal and is therefore not valid in accordance with the International Code of Zoological Nomenclature. Upon initial publication in 2020, ''Parioscorpio'' was considered the world's oldest and most primitive known scorpion, older than ''Dolichophonus'' from Scotland by several million years. In 2021, the fossils were reanalysed, and ''Parioscorpio'' was found not to be a scorpion, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waukesha Biota
The Waukesha Biota (also known as Waukesha Lagerstätte, Brandon Bridge Lagerstätte, or Brandon Bridge fauna) refers to a Konservat-Lagerstätte ( a fossil site that preserves soft bodied remains) of Early Silurian ( Telychian to Sheinwoodian) age found within the Brandon Bridge Formation in Waukesha County and Franklin, Milwaukee County, Wisconsin. It is known for the exceptional preservation of its diverse, soft-bodied and lightly skeletonized taxa, including many major taxa found nowhere else in strata of similar age. The sites discovery was announced in 1985, thus leading to a wide plethora of discoveries being made. This biota is one of the few well studied lagerstättes from the Silurian, making it very important in our understanding of Silurian faunas. Some of the taxa found here are not easily classified into known animal groups, showing that there is a great amount of studying that needs to be done on this site. Other taxa that are normally common in other Silurian d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acheronauta Stimulapis
''Acheronauta'' is a genus of extinct vermiform arthropod that lived in the early Silurian (Telychian-Sheinwoodian stages) Waukesha biota fossil site in southeast Wisconsin. This arthropod was first discovered alongside the biota in 1985, but wasn't fully described until October 2022. This creature was recognized and described as a possible early mandibulate (the grouping of arthropods including crustaceans and hexapods). This description is very important as much of the fauna of the biota remain undescribed, and it's discovery has allowed for paleontologists to get a better grasp of the diversity of the arthropod fauna at the site. Multiple phylogenetic analyses were preformed, and it seems that this arthropod forms a previously undiscovered clade with the Devonian stem-arthropod ''Captopodus'', and the somewhat enigmatic group Thylacocephala. ''Acheronauta'' has been assessed as a possible basal mandibulate, which are distinguished from other arthropods due to the presence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheloniellid
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) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods ( myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often 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 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 organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelicerata
The subphylum Chelicerata (from New Latin, , ) constitutes one of the major subdivisions of the phylum Arthropoda. It contains 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. The Chelicerata originated as marine animals in the Middle Cambrian period; the first confirmed chelicerate fossils, belonging to ''Sanctacaris'', date from 508 million years ago. 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 cover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brandon Bridge Formation
The Brandon Bridge Formation is a geologic formation in Wisconsin. It preserves fossils dating back to the Silurian period, including those of graptolites, conodonts and ''Parioscorpio.'' See also * List of fossiliferous stratigraphic units in Wisconsin * Paleontology in Wisconsin * Waukesha Biota The Waukesha Biota (also known as Waukesha Lagerstätte, Brandon Bridge Lagerstätte, or Brandon Bridge fauna) refers to a Konservat-Lagerstätte ( a fossil site that preserves soft bodied remains) of Early Silurian ( Telychian to Sheinwoodian) ... References Silurian geology of Wisconsin Silurian southern paleotropical deposits Lagerstätten {{Wisconsin-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolichophonus
''Dolichophonus'' is an extinct genus of scorpion known from the Silurian aged Gutterford Burn Eurypterid bed, in the Pentland Hills in Scotland. It is currently considered the world's oldest known scorpion, as the older '' Parioscorpio'' named in 2020 has been found to be an unrelated arthropod. lt is sometimes referred to '' Palaeophonus''. Discovery The specimen of ''Dolichophonus'' was collected by Mr Hardie of Bavelaw Castle. When he died his collection was given to the Edinburgh Museum of Science and Art (now National Museum of Scotland), where it was then studied by Malcolm Laurie. He named seven new species of Eurypterid Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 million years ago. The group is l ...s from the collection, along with this scorpion, which he named. References Prehistoric scor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scorpion
Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always ending with a stinger. The evolutionary history of scorpions goes back 435 million years. They mainly live in deserts but have adapted to a wide range of environmental conditions, and can be found on all continents except Antarctica. There are over 2,500 described species, with 22 extant (living) families recognized to date. Their taxonomy is being revised to account for 21st-century genomic studies. Scorpions primarily prey on insects and other invertebrates, but some species hunt vertebrates. They use their pincers to restrain and kill prey, or to prevent their own predation. The venomous sting is used for offense and defense. During courtship, the male and female grasp each other's pincers and dance while he tries to move her onto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nektaspida
Nektaspida (also called Naraoiida, Nektaspia and Nectaspida) is an extinct order of non- mineralised artiopodan arthropods. They are known from the mid-Cambrian to the upper Silurian. Originally classified as trilobites, which they superficially resemble, they are now placed as close relatives as members of the Trilobitomorpha within Artiopoda. The order is divided into three major families; Emucarididae, Liwiidae, and Naraoiidae. Naming history and taxonomic placement The order was originally proposed by Raymond in 1920 as Nektaspia. Størmer corrected it to Nectaspida for the 1959 ''Treatise on Invertebrate Paleontology'' to conform with the names of the other trilobite orders. Whittington described it in 1985 with the spelling Nektaspida; the revised 1997 Treatise by Raymond and Fortey uses this spelling, as do other modern works. Whittington (1985) placed the order in the Trilobita. Cotton & Braddy (2000) place it in a new "Trilobite clade" containing the Trilobita, reco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aglaspidida
Aglaspidida is an extinct order of aquatic arthropods that were once regarded as primitive chelicerates. However, anatomical comparisons demonstrate that the aglaspidids cannot be accommodated within the chelicerates, and that they lie instead within the Artiopoda, thus placing them closer to the trilobites. Aglaspidida contains the subgroups Aglaspididae and Tremaglaspididae, which are distinguished by the presence of acute/spinose genal angles and a long spiniform tailspine in the Aglaspididae. Aglaspidid fossils are found in North America (upper Mississippi valley, Missouri and Utah), Europe, Australia, and China. Certain other artiopods are believed to be closely related to the aglaspidids, including the order Strabopida Strabopidae is the only family of the order Strabopida, a group of arachnomorph arthropods. The order Strabopida contains three valid genera and one doubtful, ''Khankaspis'', '' Paleomerus'', '' Parapaleomerus'' and '' Strabops'', all assigned in ..., w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and diversification. However, such a correlation does not make a given case predicable, so ancestral characters should not be imputed to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
