Plesiosiro

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Plesiosiro
Temporal range: Upper Carboniferous
Plesiosiro madeleyi CT.jpg
CT scan
20200823 Plesiosiro madeleyi.png
Life restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Clade: Tetrapulmonata
Order: Haptopoda
Pocock, 1911
Genus: Plesiosiro
Pocock, 1911
Species:
P. madeleyi
Binomial name
Plesiosiro madeleyi
Pocock, 1911

Plesiosiro is an extinct arachnid genus known exclusively from nine specimens from the Upper Carboniferous of Coseley, Staffordshire, United Kingdom. [1] [2] The genus is monotypic, represented only by the species Plesiosiro madeleyi described by Reginald Innes Pocock in his important 1911 monograph on British Carboniferous arachnids. It is the only known member of the order Haptopoda. [3]

Contents

The original fossils have been redescribed in detail by Alexander Petrunkevitch in 1949 [4] and Dunlop in 1999. [2] A supposed example from the Coal Measures of Lancashire is a misidentification. [2]

Relationships

Plesiosiro means "close to Siro ", which is a genus of cyphophthalmid (Cyphophthalmi); the most primitive group of the living harvestmen (Opiliones). These harvestmen do, in some ways, resemble the reconstructed body plan of the haptopods.

Revisions have confirmed that Haptopoda should be treated as a separate and independent order. A 2007 study tentatively recognised a group named Schizotarsata Shultz, 2007 [5] comprising Haptopoda, Amblypygi (whip spiders), Uropygi (whip scorpions) and Schizomida (schizomids), which has been recovered subsequently in a number of other phylogenies to include fossils. [6] [7] [8] [1] All share the character of a subdivided tarsus (or foot) which gives the group its name. A 2014 analysis found that Plesisiro had chelicerae consisting of two elements, a basal paturon and a fang, which suggests a position within Tetrapulmonata. Under both equal and implied weights, Plesisiro was found to be the most basal member of a clade containing Amblypygi, Schizomida, and Uropygi (Thelyphonida s.s.), which was sister to the clade containing Araneae and Uraraneida. [1]

Names

The order has also been called Haptopodida; the ending -ida originated when Petrunkevitch (1955) [9] tried to standardize the endings of the arachnid orders.

Haptopoda originates from Greek "haptos" (= tangible, subject to the sense of touch) + "pous, podos" (= foot) and refers to its quite long front pair of legs with their subdivided tips which look as though they might have been used to 'feel' their way around in front of the animal.

Related Research Articles

<span class="mw-page-title-main">Arachnid</span> Class of arthropods

Arachnida is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroons.

<span class="mw-page-title-main">Amblypygi</span> Order of arachnids comprising whip spiders and tailless whip scorpions

Amblypygi is an order of arachnid chelicerate arthropods also known as whip spiders or tailless whip scorpions. The name "amblypygid" means "blunt tail", a reference to a lack of the flagellum that is otherwise seen in whip scorpions. Amblypygids possess no silk glands or venomous fangs. They rarely bite if threatened, but can grab fingers with their pedipalps, resulting in thorn-like puncture injuries.

<span class="mw-page-title-main">Schizomida</span> Order of shorttailed whipscorpions

Schizomida is an order of arachnids, generally less than 5 millimetres (0.20 in) in length.

<span class="mw-page-title-main">Opiliones</span> Order of arachnids (harvestmen/daddy longlegs)

The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. As of April 2017, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.

<span class="mw-page-title-main">Uropygi</span> Order of arachnids known as whip scorpions

Uropygi is an arachnid order comprising invertebrates commonly known as whip scorpions or vinegaroons. They are often called uropygids. The name "whip scorpion" refers to their resemblance to true scorpions and possession of a whiplike tail, and "vinegaroon" refers to their ability when attacked to discharge an offensive, vinegar-smelling liquid, which contains acetic acid. The order may also be called Thelyphonida. Both names, Uropygi and Thelyphonida, may be used either in a narrow sense for the order of whip scorpions, or in a broad sense which includes the order Schizomida.

<span class="mw-page-title-main">Ricinulei</span> Order of spider-like animals

Ricinulei is a small order of arachnids. Like most arachnids, they are predatory, eating small arthropods. They occur today in west-central Africa (Ricinoides) and the Americas as far north as Texas. As of 2021, 91 extant species of ricinuleids have been described worldwide, all in the single family Ricinoididae. In older works they are sometimes referred to as Podogona. Due to their obscurity they do not have a proper common name, though in academic literature they are occasionally referred to as hooded tickspiders.

<span class="mw-page-title-main">Book lung</span> Type of lung commonly found in arachnids

A book lung is a type of respiration organ used for atmospheric gas exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open ventral abdominal, air-filled cavity (atrium) and connects with its surroundings through a small opening for the purpose of respiration.

<span class="mw-page-title-main">Mesothelae</span> Suborder of spiders

The Mesothelae are a suborder of spiders that includes a single extant family, Liphistiidae, and a number of extinct families. This suborder is thought to form the sister group to all other living spiders, and to retain ancestral characters, such as a segmented abdomen with spinnerets in the middle and two pairs of book lungs. Members of Liphistiidae are medium to large spiders with eight eyes grouped on a tubercle. They are found only in China, Japan, and southeast Asia. The oldest known Mesothelae spiders are known from the Carboniferous, over 300 million years ago.

<span class="mw-page-title-main">Trigonotarbida</span> Extinct order of arachnids

The order Trigonotarbida is a group of extinct arachnids whose fossil record extends from the late Silurian to the early Permian. These animals are known from several localities in Europe and North America, as well as a single record from Argentina. Trigonotarbids can be envisaged as spider-like arachnids, but without silk-producing spinnerets. They ranged in size from a few millimetres to a few centimetres in body length and had segmented abdomens (opisthosoma), with the dorsal exoskeleton (tergites) across the backs of the animals' abdomens, which were characteristically divided into three or five separate plates. Probably living as predators on other arthropods, some later trigonotarbid species were quite heavily armoured and protected themselves with spines and tubercles. About seventy species are currently known, with most fossils originating from the Carboniferous coal measures.

<span class="mw-page-title-main">Phalangiotarbida</span> Extinct order of arachnids

Phalangiotarbida is an extinct arachnid order first recorded from the Early Devonian of Germany and most widespread in the Upper Carboniferous coal measures of Europe and North America. The last species are known from the early Permian Rotliegend of Germany.

<span class="mw-page-title-main">Tetrapulmonata</span> Clade of arachnids

Tetrapulmonata is a non-ranked supra-ordinal clade of arachnids. It is composed of the extant orders Uropygi, Schizomida, Amblypygi and Araneae (spiders). It is the only supra-ordinal group of arachnids that is strongly supported in molecular phylogenetic studies. Two extinct orders are also placed in this clade, Haptopoda and Uraraneida. In 2016, a newly described fossil arachnid, Idmonarachne, was also included in the Tetrapulmonata; as of March 2016 it has not been assigned to an order.

<span class="mw-page-title-main">Evolution of spiders</span> Origin from a chelicerate ancestor and diversification of spiders through geologic time

The evolution of spiders has been ongoing for at least 380 million years. The group's origins lie within an arachnid sub-group defined by the presence of book lungs ; the arachnids as a whole evolved from aquatic chelicerate ancestors. More than 45,000 extant species have been described, organised taxonomically in 3,958 genera and 114 families. There may be more than 120,000 species. Fossil diversity rates make up a larger proportion than extant diversity would suggest with 1,593 arachnid species described out of 1,952 recognized chelicerates. Both extant and fossil species are described annually by researchers in the field. Major developments in spider evolution include the development of spinnerets and silk secretion.

<span class="mw-page-title-main">Harvestman phylogeny</span> Order of arachnids

Harvestmen (Opiliones) are an order of arachnids often confused with spiders, though the two orders are not closely related. Research on harvestman phylogeny is in a state of flux. While some families are clearly monophyletic, that is share a common ancestor, others are not, and the relationships between families are often not well understood.

<span class="mw-page-title-main">Eophrynidae</span>

Eophrynidae is a family of the extinct arachnid order Trigonotarbida. Eophrynids lived during the Carboniferous period in what is now modern Europe and North America. The family is probably found within the "eophrynid assemblage" clade:.

<i>Palaeocharinus</i> Extinct genus of spiders

Palaeocharinus is a genus of extinct trigonotarbid arachnids known from the Devonian of western Europe. The genus was first found and described in the Rhynie chert in the 1920s by Arthur Stanley Hirst and S. Maulik. The family to which the genus belongs may be paraphyletic.

<span class="mw-page-title-main">Phrynidae</span> Family of whip scorpions

Phrynidae is a family of amblypygid arachnida arthropods also known as whip spiders and tailless whip scorpions. Phrynidae species are found in tropical and subtropical regions in North and South America. Some species are subterranean; all are nocturnal. At least some species of Phrynidae hold territories that they defend from other individuals.

<span class="mw-page-title-main">Uraraneida</span> Order of arachnids

Uraraneida is an extinct order of Paleozoic arachnids related to modern spiders. Two genera of fossils have been definitively placed in this order: Attercopus from the Devonian of United States and Permarachne from the Permian of Russia. Like spiders, they are known to have produced silk, but lack the characteristic spinnerets of modern spiders, and retain elongate telsons.

<i>Paracharon</i> Genus of whip scorpions

Paracharon is a genus of tailless whip scorpion. A single species, Paracharon caecus has been described. It is endemic to Guinea-Bissau in West Africa It is one of two living genera of the family Paracharontidae, alongside the South American Jorottui. It is a troglobite having no eyes, with P. caecus found living in termite nests.

<i>Weygoldtina</i> Extinct genus of whip scorpions

Weygoldtina is an extinct genus of tailless whip scorpion known from Carboniferous period, and the only known member of the family Weygoldtinidae. It is known from two species described from North America and England and originally described in the genus Graeophonus, which is now considered a nomen dubium.

<span class="mw-page-title-main">Paracharontidae</span> Family of whip scorpions

Paracharontidae is an arachnid family within the order Amblypygi. Paracharontidae and the extinct Weygoldtinidae from the Carboniferous form the suborder Paleoamblypygi, the sister group to the remaining Amblypygi. The family contains two genera: Paracharon, containing the single species Paracharon caecus Hansen, 1921 from Guinea-Bissau in West Africa, and Jorottui with the single species Jorottui ipuanai from Colombia in northern South America. Paracharonopsis from the Eocene (Ypresian) aged Cambay amber of India was initially assigned to this family but this was later questioned and it has since been reassigned to Euamblypygi. Both living species are troglobites, having no eyes, with P. caecus living in termite nests, while J. ipuanai inhabits caves.

References

  1. 1 2 3 Garwood, Russell J.; Dunlop, Jason (2014). "Three-dimensional reconstruction and the phylogeny of extinct chelicerate orders". PeerJ. 2: e641. doi: 10.7717/peerj.641 . ISSN   2167-8359. PMC   4232842 . PMID   25405073.
  2. 1 2 3 Dunlop, Jason A. (2011). "A redescription of the Carboniferous arachnid Plesiosiro madeleyi Pocock, 1911 (Arachnida: Haptopoda)". Transactions of the Royal Society of Edinburgh: Earth Sciences. 90 (1): 29–47. doi:10.1017/S0263593300002492. ISSN   0263-5933.
  3. Reginald Innes Pocock (1911). A Monograph of the Terrestrial Carboniferous Arachnida of Great Britain. Monographs of the Palaeontographical Society, London. pp.  1–84.
  4. Alexander Petrunkevitch (1949). "A study of Palaeozoic Arachnida". Transactions of the Connecticut Academy of Arts and Sciences . 37: 69–315.
  5. Jeffrey W. Shultz (2007). "A phylogenetic analysis of the arachnid orders based on morphological characters" (PDF). Zoological Journal of the Linnean Society . 150 (2): 221–265. doi: 10.1111/j.1096-3642.2007.00284.x .
  6. Wang, Bo; Dunlop, Jason A.; Selden, Paul A.; Garwood, Russell J.; Shear, William A.; Müller, Patrick; Lei, Xiaojie (2018). "Cretaceous arachnid Chimerarachne yingi gen. et sp. nov. illuminates spider origins". Nature Ecology & Evolution. 2 (4): 614–622. doi:10.1038/s41559-017-0449-3. ISSN   2397-334X. PMID   29403075. S2CID   4239867.
  7. Garwood, Russell J.; Dunlop, Jason A.; Knecht, Brian J.; Hegna, Thomas A. (2017). "The phylogeny of fossil whip spiders". BMC Evolutionary Biology. 17 (1): 105. doi: 10.1186/s12862-017-0931-1 . ISSN   1471-2148. PMC   5399839 . PMID   28431496.
  8. Garwood, Russell J.; Dunlop, Jason A.; Selden, Paul A.; Spencer, Alan R. T.; Atwood, Robert C.; Vo, Nghia T.; Drakopoulos, Michael (2016). "Almost a spider: a 305-million-year-old fossil arachnid and spider origins". Proceedings of the Royal Society B: Biological Sciences. 283 (1827): 20160125. doi: 10.1098/rspb.2016.0125 . ISSN   0962-8452. PMC   4822468 . PMID   27030415.
  9. Alexander Petrunkevitch (1955). "Arachnida". In R. C. Moore (ed.). Part P, Arthropoda 2. Treatise on Invertebrate Paleontology. Lawrence: Geological Society of America and University of Kansas Press. pp. 42–162.