# Stenochirus > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Stenochirus > Markdown URL: https://mediated.wiki/source/Stenochirus.md > Source: https://en.wikipedia.org/wiki/Stenochirus > Source revision: 1354690939 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Extinct genus of crustaceans}} {{Automatic taxobox | fossil_range = {{fossil range|Callovian|Tithonian|[Callovian](/source/Callovian)-[Tithonian](/source/Tithonian)}} | image = Stenochirus fossils.jpg | image_caption = Fossils of ''S. mayeri'' (left) and ''S. angustus'' (right) | taxon = Stenochirus | authority = Oppel, 1861 | type_species = {{extinct}}'''''Bolina angusta''''' | type_species_authority = [Münster](/source/Georg_zu_M%C3%BCnster), 1839 | subdivision_ranks = Species | subdivision = *{{extinct}}'''''S. angustus''''' Münster, 1839 *{{extinct}}'''''S. mayeri''''' Oppel, 1862 *{{extinct}}'''''S. vahldieki''''' Schweigert, Garassino & Riou, 2006 | synonyms = {{collapsible list|bullets=true|title=''S. angustus'' synonymy |''Bolina angusta'' Münster, 1839 }} }} '''''Stenochirus''''' is an [extinct](/source/extinct) [genus](/source/genus) of [decapod](/source/Decapoda) [crustacean](/source/crustacean)s that lived from the [Callovian](/source/Callovian) to [Tithonian](/source/Tithonian) stages of the [Jurassic](/source/Jurassic) period. Its fossils have been found in [Germany](/source/Germany) and [France](/source/France). ==Discovery and naming== thumb|left|upright|''S. angustus'' as illustrated in Münster's 1839 paper, originally labelled as ''Bolina angusta'' Remains of ''Stenochirus'' have been described before the genus was named. [Georg zu Münster](/source/Georg_zu_M%C3%BCnster) established the genus ''Bolina'' in 1839 and assigned to species to it, ''B. angusta'' and ''B. pustulosa'' (the [type species](/source/type_species)), both originating from the [Tithonian](/source/Tithonian)-aged [Solnhofen Limestone](/source/Solnhofen_Limestone) in [Bavaria](/source/Bavaria).{{Cite book |last1=Münster |first1=Georg Herbert |url=https://www.biodiversitylibrary.org/bibliography/120022 |title=Beitraege zur Petrefacten-Kunde : mit XXX. nach der Natur gezeichneten tafeln |last2=Münster |first2=Georg Herbert |date=1839 |publisher=in Commission der Buchner'schen Buchhandlung |location=Bayreuth}} 22 years later in 1861, [Albert Oppel](/source/Albert_Oppel) points out that the genus name ''Bolina'' is [preoccupied](/source/preoccupied) by a [cnidaria](/source/cnidaria)n, and reassigns the two species into separate genera. He erects the new genera ''Stenochirus'' and ''[Pseudastacus](/source/Pseudastacus)'', which ''B. angusta'' and ''B. pustulosa'' became the type species of respectively, the former now renamed as ''Stenochirus angustus''.{{Cite journal |last=A |first=Oppel |date=1861 |title=Die Arten der Gattungen Eryma, Pseudastacus, Magila und Etallonia. |url=https://www.marinespecies.org/traits./aphia.php?p=sourceget&id=230972 |format=PDF |journal=Jahreshefte des Vereins für Vaterlandische Naturkunde in Wurttemberg |language=de |volume=17 |pages=355–364}} In addition to the type species, two other species have been assigned to the genus. Oppel described a second species in 1862, which he named ''Stenochirus mayeri'' after Charles Mayer-Eymar, based on one specimen preserved showing its underside collected from the Solnhofen Limestone.{{Cite book |last1=Oppel |first1=Carl Albert |url=http://archive.org/details/palaeontologisch113oppe |title=Palaeontologische Mittheilungen aus dem Museum des koenigl. bayer. Staates |last2=Zittel |first2=Karl Alfred von |last3=Boehm |first3=Georg |last4=Bayerisches Nationalmuseum |date=1862 |publisher=Stuttgart : Ebner & Seubert |others=Smithsonian Libraries}} The specific name has been misspelled as ''meyeri'' in some publications, due to mistakenly believing the species is named after Hermann v. Meyer.{{Cite journal |last1=Garassino |first1=Alessandro |last2=Schweigert |first2=Guenter |date=January 2006 |title=The Upper Jurassic Solnhofen decapod crustacean fauna: Review of the types from old descriptions. Part I. Infraorders Astacidea, Thalassinidea, and Palinura |url=http://mmtk.ginras.ru/pdf/garassino_schweigert2006.pdf |journal=Memorie della Società italiana di Scienze naturali e del Museo civico di Storia naturale di Milano |volume=34 |issue=1 |pages=1–64}} In 2006, the third species ''Stenochirus vahldieki'' was named from remains found in the [lagerstätte](/source/lagerst%C3%A4tte) at [La Voulte-sur-Rhône](/source/La_Voulte-sur-Rh%C3%B4ne_(lagerst%C3%A4tte)), France. This site dates back to the [Callovian](/source/Callovian) stage of the [Middle Jurassic](/source/Middle_Jurassic) period, making ''S. vahldieki'' the oldest known species of the genus.{{Cite journal |last1=Schweigert |first1=Günter |last2=Garassino |first2=Alessandro |date=2006-03-20 |title=First record of ''Stenochirus'' Oppel, 1861 (Crustacea: Decapoda: Stenochiridae) from the Callovian (Middle Jurassic) of La Voulte-sur-Rhône |url=http://www.schweizerbart.de/papers/njgpm/detail/2006/91571/First_record_of_Stenochirus_Oppel_1861_Crustacea_D?af=crossref |journal=Neues Jahrbuch für Geologie und Paläontologie - Monatshefte |language=en |volume=2006 |issue=2 |pages=65–77 |doi=10.1127/njgpm/2006/2006/65 |issn=0028-3630|url-access=subscription }} ==Description== Measuring around {{convert|3|cm|abbr=on|in}} long, ''Stenochirus'' was a small [crustacean](/source/crustacean) with a [crayfish](/source/crayfish)-like build and smooth [exoskeleton](/source/exoskeleton). The [carapace](/source/carapace) is cylindrical, with a deep cervical groove stretching across the top and sides, as well as two shallow grooves behind it running parallel to each other. The back of the carapace has slightly convex margin. The [rostrum](/source/Rostrum_(anatomy)) is long and has four forward-pointing teeth on its sides. A pair of short stalks connect the [compound eye](/source/compound_eye)s to the head. The [antennae](/source/Antenna_(biology)) are very long, exceeding the rest of the body in length. thumb|left|upright|Comparison of the pincers of ''S. mayeri'' (left) and ''S. angustus'' (right) The frontmost pair of [pereiopod](/source/pereiopod)s are very long and slender, ending with [pincers](/source/Pincer_(biology)). Both "fingers" of each pincer have rows of elongated teeth-like serrations and curve at the tip. In ''S. angustus'', the frontmost pereiopods are six times as long as they are wide, and the pincer "fingers" are equal in length. Meanwhile, the frontmost pereiopods of ''S. mayeri'' are narrower, being 12 times longer than they are wide, and the movable pincer "finger" is longer than the fixed one. The first [abdomen](/source/abdomen) segment is smaller than the others, which are around the same length and subrectangular in shape. The [telson](/source/telson) also has a subrectangular shape, as well as a weak groove, two pairs of spines and two ridges starting at the front of the upper surface which end with small spines on the side margins. Both the [endopod](/source/endopod)s and [exopod](/source/exopod)s of the [uropod](/source/uropod)s have weak ridges, the latter additionally having a small spine on the outer margin. ==Classification== ''Stenochirus'' is the [type genus](/source/type_genus) of the [family](/source/Family_(taxonomy)) [Stenochiridae](/source/Stenochiridae), assigned as such when the family was established without formal diagnosis by [Karl Beurlen](/source/Karl_Beurlen) in 1928.{{Cite journal |last=Beurlen |first=Karl |date=1928-01-01 |title=Die Decapoden des Schwäbischen Jura, mit Ausnahme der aus den oberjurassischen Plattenkalken stammenden. Beiträge zur Systematik und Stammesgeschichte der Decapoden |url=https://www.schweizerbart.de/papers/palae/detail/70/67587/Die_Decapoden_des_Schwabischen_Jura_mit_Ausnahme_der_aus_den_oberjurassischen_Plattenkalken_stammenden_Beitrage_zur_Systematik_und_Stammesgeschichte_der_Decapoden |journal=Palaeontographica |language=de |pages=115–278}} Beurlen initially erected it as a [subfamily](/source/subfamily) named Stenochirinae, but would elevate it to family level in 1930.{{Cite journal |last=Beurlen |first=Karl |date=1930 |title=Vergleichende Stammesgeschichte: Grundlagen, Methoden, Probleme unter besonderer Berück-sichtigung der höheren Krebse |journal=Nature |language=de |volume=129 |issue=3264 |pages=745 |doi=10.1038/129745a0 |issn=1476-4687|doi-access=free }} Although [Martin Glaessner](/source/Martin_Glaessner) assigned ''Stenochirus'' to [Erymidae](/source/Erymidae) in 1929, he later placed it as an indeterminate [astacidea](/source/astacidea)n when writing for the ''[Treatise on Invertebrate Paleontology](/source/Treatise_on_Invertebrate_Paleontology)'' in 1969.{{Cite book |last=Glaessner |first=M. F. |url=https://books.google.com/books?id=_FjTywEACAAJ |title=Fossilium catalogus: Animalia. Crustacea decapoda |date=1929 |publisher=Junk |language=la}}{{Cite journal |last1=Moore |first1=R. C. |last2=Brooks |first2=H. K. |last3=Glaessner |first3=M. F. |last4=Rolfe |first4=W. D. Ian |last5=Manning |first5=Raymond B. |last6=Holthuis |first6=L. B. |last7=Hessler |first7=Robert R. |date=1969-01-01 |title=Part R, Arthropoda 4, vol. 1 & 2, ch. 4, p. 295-566 |url=https://journals.ku.edu/InvertebratePaleo/article/view/5629 |journal=Treatise on Invertebrate Paleontology |language=en |doi=10.17161/dt.v0i0.5629 |issn=2153-621X}} Garassino & Schweigert (2006) would resurrect the taxon Stenochiridae and give the family a formal diagnosis, reassigning ''Stenochirus'' as its only genus. In 2013, analysis by Karasawa ''et al.'' found that the supposed family Chilenophoberidae is [paraphyletic](/source/paraphyletic), as ''Stenochirus'' is nested within as a sister taxon to ''[Pseudastacus](/source/Pseudastacus)''. They therefore declared Chilenophoberidae as a [junior synonym](/source/junior_synonym) of Stenochiridae, and thus more genera were moved into the family. The following [cladogram](/source/cladogram) shows the placement of ''Stenochirus'' within Stenochiridae according to the study:{{Cite journal |last1=Karasawa |first1=Hiroaki |last2=Schweitzer |first2=Carrie E. |last3=Feldmann |first3=Rodney M. |date=2013-01-01 |title=Phylogeny and systematics of extant and extinct lobsters |journal=Journal of Crustacean Biology |language=en |volume=33 |issue=1 |pages=78–123 |doi=10.1163/1937240X-00002111 |issn=0278-0372|doi-access=free |bibcode=2013JCBio..33...78K }} {{clade |label1=[Stenochiridae](/source/Stenochiridae) |1={{clade |2=''[Palaeophoberus](/source/Palaeophoberus)'' |3=''[Tillocheles](/source/Tillocheles)'' |1={{clade |2=''[Chilenophoberus](/source/Chilenophoberus)'' |1={{clade |1='''''Stenochirus''''' |2=''[Pseudastacus](/source/Pseudastacus)'' }} }} }} }} ==References== {{reflist}} ==External links== {{Portal|Crustaceans|Paleontology}} *{{commons category-inline|Stenochirus|''Stenochirus''}} {{Taxonbar|from1=Q123575455}} Category:Jurassic crustaceans Category:Solnhofen fauna Category:Fossil taxa described in 1861 Category:Decapod genera --- Adapted from the Wikipedia article [Stenochirus](https://en.wikipedia.org/wiki/Stenochirus) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Stenochirus?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.