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38-599: Stylonurina is one of two suborders of eurypterids , a group of extinct arthropods commonly known as "sea scorpions". Members of the suborder are collectively and informally known as "stylonurine eurypterids" or "stylonurines". They are known from deposits primarily in Europe and North America , but also in Siberia . Compared to the other suborder, Eurypterina , the stylonurines were comparatively rare and retained their posterior prosomal appendages for walking. Despite their rarity,

76-456: A cohors (plural cohortes ). Some of the plant families still retain the names of Linnaean "natural orders" or even the names of pre-Linnaean natural groups recognized by Linnaeus as orders in his natural classification (e.g. Palmae or Labiatae ). Such names are known as descriptive family names. In the field of zoology , the Linnaean orders were used more consistently. That is,

114-505: A capital letter. For some groups of organisms, their orders may follow consistent naming schemes . Orders of plants , fungi , and algae use the suffix -ales (e.g. Dictyotales ). Orders of birds and fishes use the Latin suffix -iformes meaning 'having the form of' (e.g. Passeriformes ), but orders of mammals and invertebrates are not so consistent (e.g. Artiodactyla , Actiniaria , Primates ). For some clades covered by

152-566: A distinct rank of biological classification having its own distinctive name (and not just called a higher genus ( genus summum )) was first introduced by the German botanist Augustus Quirinus Rivinus in his classification of plants that appeared in a series of treatises in the 1690s. Carl Linnaeus was the first to apply it consistently to the division of all three kingdoms of nature (then minerals , plants , and animals ) in his Systema Naturae (1735, 1st. Ed.). For plants, Linnaeus' orders in

190-566: A rounded posterior margin to the metastoma and the prosomal appendage III bearing single fixed spines. Brachyopterus is also one of the oldest known genera of eurypterid , being from the Middle Ordovician . The least well-supported group is the Stylonuroidea , containing the problematic genera Stylonurus and Stylonurella , partly due to the incomplete nature of the only known specimen of Stylonurus powriei which does not preserve

228-540: A time when most continents were widely separated, the clade is the eurypterid clade with the most cosmopolitan distribution. Like other eurypterines, they are most common in Laurentia, Baltica and Avalonia, but are also found commonly in other paleocontinents . Fossil remains have been recovered from Australia , Libya , Algeria , Morocco , Florida , Saudi Arabia , Iberia , South America , vast swaths of Gondwana , Bohemia and Siberia . The earliest pterygotoids are from

266-597: A wide variety of different genera and species. They are all unified by possessing transverse sutures on the ventral plates and lacking a modified podomere 7a on appendage VI. The suborder is divided into four major superfamilies; the Rhenopteroidea , Stylonuroidea , Kokomopteroidea and Mycteropoidea . The most primitive of these, the Rhenopteroidea, includes several previously enigmatic genera, such as Brachyopterus , Kiaeropterus and Rhenopterus , all united by

304-419: Is determined by a taxonomist , as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with

342-599: Is the last major radiation of the eurypterids before their extinction in the Permian . Though the Eurypterina contains several famous giant eurypterids such as Pterygotus and Jaekelopterus , the Stylonurina gave rise to large forms as well, several larger than a metre in length. The largest known stylonurine was Hibbertopterus scouleri , with a potential length of almost 2 metres (6 ft 7 in). Stylonurina contains

380-503: Is the most species-rich clade, with 56 species, followed by the Adelophthalmoidea with 43 species; as sister taxa , they comprise the most derived eurypterines. Pterygotioidea includes the pterygotids , which are the only eurypterids known to have a cosmopolitan distribution. Though more numerous both in specimens and taxa, the eurypterines have the shorter temporal range of the two eurypterid suborders. They first appeared around

418-646: The Carboniferous and Permian , the genus gained an almost cosmopolitan distribution. The basalmost species in the entire clade are from Baltica and most of the evolution within the basal members took place in Laurussia . By the Devonian, representatives were found in both Siberia and Australia long before the formation of Pangaea. Although the Pterygotoidea only existed for a period of about 40 million years during

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456-520: The International Code of Zoological Nomenclature , several additional classifications are sometimes used, although not all of these are officially recognized. In their 1997 classification of mammals , McKenna and Bell used two extra levels between superorder and order: grandorder and mirorder . Michael Novacek (1986) inserted them at the same position. Michael Benton (2005) inserted them between superorder and magnorder instead. This position

494-603: The Megalograptoidea is thought to be relatively primitive (between Onychopterella and the Eurypteroidea ) because they lack a synapomorphy of all more derived swimming forms; the modified distal margin of the sixth podomere of the swimming leg. This position is not necessarily true, since the sixth podomere in the swimming leg resembles the reduced podomere found in the Mixopteridae , and they might instead belong between

532-458: The Stylonuroidea and the Mycteropoidea . In both superfamilies, the adaptations to this lifestyle involves modifications to the spines on their anterior prosomal appendages for raking through the substrate of their habitats. Rhenopteroids , kokomopterids and parastylonurids retained primitive prosomal appendages II-IV that were unsuited for sweep-feeding and likely adopted scavenging, whilst

570-769: The Systema Naturae and the Species Plantarum were strictly artificial, introduced to subdivide the artificial classes into more comprehensible smaller groups. When the word ordo was first consistently used for natural units of plants, in 19th-century works such as the Prodromus Systematis Naturalis Regni Vegetabilis of Augustin Pyramus de Candolle and the Genera Plantarum of Bentham & Hooker, it indicated taxa that are now given

608-603: The cosmopolitan distribution of the pterygotoids , though were not as common nor as successful. Adelophthalmoids were the longest lasting clade of eurypterines, becoming extinct in the Middle Permian , this is in part due to the survival of Adelophthalmus beyond the Middle Devonian . The earliest records of the genus are from the Early Devonian of western Germany , but following the amalgamation of Pangaea during

646-567: The hardieopterids may have been benthic bottomdwellers living partially buried in the substrate. Stylonuroids have fixed spines on appendages II-IV which could have been used as dragnets to rake through the sediments and thus entangling anything in their way, whilst the mycteropoids, which have some of the most extreme adaptations, likely were more selective and specialized. Mycteropoids possess modified blades on their anterior prosomal appendages that feature sensory setae. The tactile function of these might have allowed mycteropoids to select prey from

684-660: The Eurypteroidea and Carcinosomatoidea. In contrast to the Megalograptoidea, the Eurypteroidea is a rather well-known clade that contains around 90% of all known eurypterid specimens. They were closely related, supported by numerous similarities, to the Carcinosomatoidea. The Carcinosomatoidea have a poorly resolved internal phylogeny, though can be easily recognised by scorpion -like appearance and heavily spinose appendages. Pterygotioidea and Adelophthalmoidea are

722-417: The absolute majority of both known eurypterid species and known specimens, though the morphology of the walking stylonurines is almost as diverse in appearance, and the fossil record of the eurypterines may therefore simply be more complete than that of the stylonurines, possibly due to varying habitat preferences. The most basal eurypterines with swimming legs, the genus Onychopterella , are known from

760-412: The anterior prosomal appendages or any details of the ventral structures. Specimens of other members of the group are similarly incomplete, with Stylonurella spinipes not preserving the metastoma or pretelson and telson and Pagea sturrocki not preserving any dorsal structures. The superfamilies Mycteropoidea and Kokomopteroidea are sister groups, united by a median ridge on the carapace between

798-543: The earliest records of the genus are from Baltica and Eurypterus was thus likely an invasive genus in Laurentia, albeit one that managed to adapt well to the new habitats. The majority of carcinosomatoid taxa are also known from Laurentia, Baltica and Avalonia. Isolated and fragmentary fossils from the Late Silurian of Vietnam and the Czech Republic show that the terranes of Annamia and Perunica were within

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836-492: The east coast of Gondwana close to the equator (a region that today is South Africa) from the Late Ordovician. It is not known whether or not the swimming forms originated here or not, but it is speculated that they migrated from Laurentia , since most stylonurines and basal swimming forms are predominantly known from Laurentia and Gondwana otherwise completely lacks basal swimming forms. The megalograptoids were likely

874-529: The first major and comprehensive analysis of the suborder, which permitted a substantial systematic revision and comparisons to other eurypterid clades. The phylogenetic analysis established that Stylonurina indeed was a monophyletic group composed of four clades: the Rhenopteroidea , Stylonuroidea , Kokomopteroidea and Mycteropoidea . These superfamilies in turn contain the following families (and one genus incertae sedis ): Suborder Stylonurina Diener, 1924 The cladogram presented below showcases

912-850: The first major successful group of eurypterids, evidenced by a Late Ordovician radiation. All known members of the Megalograptoidea are from the Middle to Late Ordovician of Laurentia, though potential records from the Middle Silurian of Baltica are known in the form of the genus Holmipterus suecicus (though its classification as a megalograptoid is questionable). Eurypteroids are known from Laurentia and Baltica, with one known species from Avalonia . Eurypterus and other eurypteroids appear to have been unable to spread beyond Laurussian waters. The genus Eurypterus in particular dominated many Silurian eurypterid faunas of Laurentia. Despite its abundance, it appears to not have originated in Laurentia,

950-521: The geographical range of the carcinosomatoids. Only a few basal carcinosomatoids (e.g. Carcinosoma and Paracarcinosoma ) have been found in deeper waters whilst the more derived forms, such as Mixopterus and Lanarkopterus have not. Basal carcinosomatoids ( Carcinosomatidae ) are likely responsible for the fossil remains in Vietnam and the Czech Republic and may have had a distribution similar to

988-417: The lateral eyes and a distal thickening to the podomeres of the prosomal appendages. Though sometimes classified as an order separate from Eurypterida itself, the hibbertopterids are clearly recovered as stylonurine eurypterids in the latest analyses of the group. Strategies for sweep-feeding (raking through the substrate in search of prey) evolved independently in two of the four stylonurine superfamilies,

1026-567: The latest Llandovery of Scotland , Laurentia and South China and this mobility makes it difficult to pinpoint the geographical origin of the clade, though it is speculated to have been close to or in Laurentia like the Adelophthalmoidea. Eurypterina contains eight superfamilies - Onychopterelloidea , Moselopteroidea , Megalograptoidea , Eurypteroidea , Carcinosomatoidea , Waeringopteroidea , Adelophthalmoidea and Pterygotioidea . The relationships between them remain somewhat unclear,

1064-698: The orders in the zoology part of the Systema Naturae refer to natural groups. Some of his ordinal names are still in use, e.g. Lepidoptera (moths and butterflies) and Diptera (flies, mosquitoes, midges, and gnats). In virology , the International Committee on Taxonomy of Viruses 's virus classification includes fifteen taxomomic ranks to be applied for viruses , viroids and satellite nucleic acids : realm , subrealm , kingdom , subkingdom, phylum , subphylum , class, subclass, order, suborder, family, subfamily , genus, subgenus , and species. There are currently fourteen viral orders, each ending in

1102-656: The phylogeny of the Stylonurina as presented by Lamsdell et al. (2010). Alkenopterus (here shown as a rhenopterid ) has since been reclassified as a basal eurypterine . Brachyopterus Kiaeropterus Brachyopterella Alkenopterus Rhenopterus Parastylonurus Stylonurella Pagea Stylonurus Laurieipterus Ctenopterus Lamontopterus Kokomopterus Hardieopterus Tarsopterella Hallipterus Drepanopterus Cyrtoctenus Hibbertopterus Woodwardopterus Megarachne Mycterops Suborders What does and does not belong to each order

1140-547: The precursor of the currently used International Code of Nomenclature for algae, fungi, and plants . In the first international Rules of botanical nomenclature from the International Botanical Congress of 1905, the word family ( familia ) was assigned to the rank indicated by the French famille , while order ( ordo ) was reserved for a higher rank, for what in the 19th century had often been named

1178-494: The rank of family (see ordo naturalis , ' natural order '). In French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille (plural: familles ) was used as a French equivalent for this Latin ordo . This equivalence was explicitly stated in the Alphonse Pyramus de Candolle 's Lois de la nomenclature botanique (1868),

Stylonurina - Misplaced Pages Continue

1216-635: The same time as the Stylonurina in the Middle Ordovician . The suborder faced a slow extinction during the Middle and Late Devonian , possibly tied to the emergence of jawed vertebrates. Every Eurypterine genus and lineage went extinct before the Carboniferous save for Adelophthalmus which would go extinct in the Early Permian , millions of years before the Permian-Triassic extinction event that ended

1254-552: The sediments in a way that stylonuroids could not. Historically, the phylogeny and systematics of the Stylonurina have been far less well understood and less resolved than that of the Eurypterina . Many historical analyses were limited in scope or resolution and the unique hibbertopterids have even on occasion been suggested to be a separate, but closely related, order to Eurypterida, but have lacked an analysis either proving or disproving such an idea. Lamsdell et al . (2011) performed

1292-599: The stylonurines have the longest temporal range of the two suborders. The suborder contains some of the oldest known eurypterids, such as Brachyopterus , from the Middle Ordovician as well as the youngest known eurypterids, from the Late Permian . They remained rare throughout the Ordovician and Silurian, though the radiation of the mycteropoids (a group of large sweep-feeding forms) in the Late Devonian and Carboniferous

1330-435: The stylonurines. The Stylonurina and Eurypterina are most easily distinguished by the morphology of the posteriormost prosomal appendage. In the Stylonurina, this appendage takes the form of a long and slender walking leg, lacking a modified spine (termed podomere 7a). In the Eurypterina, the leg is most usually modified and broadened into a swimming paddle and always includes a podomere 7a. Swimming eurypterines represent

1368-559: The suffix -virales . Eurypterina Eurypterina is one of two suborders of eurypterids , an extinct group of chelicerate arthropods commonly known as "sea scorpions". Eurypterine eurypterids are sometimes informally known as "swimming eurypterids". They are known from fossil deposits worldwide, though primarily in North America and Europe . Seventy-five percent of eurypterid species are eurypterines; this represents 99% of specimens. The superfamily Pterygotioidea

1406-407: The two most derived clades as well as the most taxonomically diverse ones. Adelophthalmoidea contains 43 species, whereas Pterygotioidea contains 56. The superfamilies classified as part of Eurypterina contain the following families: Suborder Eurypterina Burmeister, 1843 Eurypterines are characterised by the transformation of the posteriormost prosomal appendage into a swimming paddle, one of

1444-418: Was adopted by Systema Naturae 2000 and others. In botany , the ranks of subclass and suborder are secondary ranks pre-defined as respectively above and below the rank of order. Any number of further ranks can be used as long as they are clearly defined. The superorder rank is commonly used, with the ending -anae that was initiated by Armen Takhtajan 's publications from 1966 onwards. The order as

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