# Mitrate

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Mitrate
> Markdown URL: https://mediated.wiki/source/Mitrate.md
> Source: https://en.wikipedia.org/wiki/Mitrate
> Source revision: 1348139625
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{Short description|Extinct order of marine invertebrates}}
{{Automatic taxobox
| fossil_range = [Cambrian](/source/Cambrian) ([Guzhangian](/source/Guzhangian))–[Carboniferous](/source/Carboniferous) ([Morrowan](/source/Morrowan))<ref>{{Cite PBDB|taxon|31183|Mitrata}}</ref> {{Geological range|Guzhangian|318.6|}}
| taxon = Mitrata
| image = Rhenocystis latipedunculata.png
| image_caption = ''Rhenocystis latipedunculata'' ventral/flat (B1) and dorsal/convex (B2) surfaces
| authority = Jaekel, 1918
| subdivision_ranks = Taxa
| subdivision = See Taxa
}}

'''Mitrates''' are an extinct group of [echinoderm](/source/echinoderm)s, which are grouped with the [cornute](/source/cornuta)s and the basal ''Ceratocystis'' to form the [Stylophora](/source/Stylophora).  Mitrates were central to the now-disproven<ref name=Boisset2024>{{cite journal|last1=Boisset |first1=Thomas |last2=Lefebvre |first2=Bertrand |last3=Mooi |first3=Rich |last4=Kroh |first4=Andreas |last5=Winkler |first5=Viola |last6=Adrien |first6=Jérôme |last7=Martin |first7=Markus J. |year=2024 |title=Insights into stylophoran anatomy and taphonomy based on an exceptionally preserved mitrate from the Lorraine Group (Upper Ordovician) of New York, USA |journal=Cah. Biol. Mar. |volume=65 |pages=511–516 |doi=10.21411/CBM.A.33CFD1AB}}</ref> [calcichordate hypothesis](/source/calcichordate_hypothesis) of [chordate](/source/chordate) origins, but are now seen as either pre-radial-symmetry [stem-group](/source/stem-group) echinoderms,<ref>{{cite journal|last1=Rahman |first1=Imran A. |last2=Zamora |first2=Samuel |date=July 2024 |title=Origin and early evolution of echinoderms |journal=Annual Review of Earth and Planetary Sciences |volume=52 |pages=295–320 |issue=1 |doi=10.1146/annurev-earth-031621-113343|bibcode=2024AREPS..52..295R |hdl=10141/623070 |url=http://zaguan.unizar.es/record/145576 |hdl-access=free }}</ref> or as a derived group either within the [blastozoa](/source/blastozoa)ns<ref>{{cite journal|last1=Mooi |first1=Rich |last2=Lefebvre |first2=Bertrand |last3=Guensburg |first3=Thomas E. |last4=Nohejovlá |first4=Martina |last5=Dupichaud |first5=Christophe |date=December 2024 |title=Approaches to understanding echinoderm origins. Part 2: Questioning conceptual models |journal=Cahiers de Biologie Marine |volume=65 |pages=463–490 |doi=10.21411/CBM.A.604F2876}}</ref> or near to the origin of [crinoids](/source/crinoids).<ref>{{cite journal|last1=Guensburg |first1=Thomas E. |last2=Sprinkle |first2=James |last3=Mooi |first3=Rich |last4=Lefebvre |first4=Bertrand |last5=David |first5=Bruno |last6=Roux |first6=Michel |last7=Derstler |first7=Kraig |year=2020 |title=Athenacrinus n. gen. and other early echinoderm taxa inform crinoid origin and arm evolution |journal=Journal of Paleontology |volume=94 |number=2 |pages=311–333 |doi=10.1017/jpa.2019.87}}</ref>

==Morphology==
The organisms were a few millimetres long.<ref name=Gee2000/>  Like the echinoderms, they are covered in armour plates, each of which comprises a single crystal of [calcite](/source/calcite).  This is one of the features they share with the latter group, along with a [water vascular system](/source/water_vascular_system), only discovered in 2019.<ref>{{Cite journal |last1=Lefebvre |first1=Bertrand |last2=Guensburg |first2=Thomas E. |last3=Martin |first3=Emmanuel L. O. |last4=Mooi |first4=Rich |last5=Nardin |first5=Elise |last6=Nohejlová |first6=Martina |last7=Saleh |first7=Farid |last8=Kouraïss |first8=Khaoula |last9=El Hariri |first9=Khadija |date=2019-02-01 |title=Exceptionally preserved soft parts in fossils from the Lower Ordovician of Morocco clarify stylophoran affinities within basal deuterostomes |journal=Geobios |volume=52 |pages=27–36 |doi=10.1016/j.geobios.2018.11.001 |issn=0016-6995 |doi-access=free |bibcode=2019Geobi..52...27L }}</ref> However, they do not display the familiar fivefold symmetry that more recent echinoderms possess, instead being close to (but not fully) bilaterally symmetrical.<ref name=Gee2000/><ref>{{cite web |url=http://palaeos.com/metazoa/deuterostomia/homalozoa/stylophora.html |title=Palaeos Metazoa: Deuterostomia: Stylophora |access-date=2023-03-04}}</ref>

Their heads had two sides; one, flat, was covered with large "pavement-like"<ref name=Gee2000/> plates, the other, convex, bore smaller plates.<ref name=Gee2000/> 
Their tails were long and segmented, resembling the stalk of a crinoid or the arm of a brittlestar.<ref name=Gee2000/> At the opposite end was a hole which may have been mouth or anus - or both.<ref name=Gee2000/>

They also bear features reminiscent of [pharyngeal slit](/source/pharyngeal_slit)s,<ref name=Jefferies1986>{{cite book |author = Jefferies, R. P. S. |year = 1986 |title = The Ancestry of the Vertebrates |publisher = British Museum (Natural History) |isbn =}}</ref> a character lost in other echinoderms but present in hemichordates.<ref name=Gee2000/> This caused R. P. S. Jefferies to hold them as the [ancestor of all chordates](/source/Calcichordate_hypothesis), a theory that has since been disproven.<ref name=Boisset2024 />

==Behaviour==

The mitrate ''[Rhenocystis latipedunculata](/source/Rhenocystis)'' has been found with associated trace fossils.<ref name=Sutcliffe2000>{{Cite journal |last=Sutcliffe |first=Owen E. |last2=Südkamp |first2=Wouter H. |last3=Jefferies |first3=Richard P. S. |date=March 2000 |title=Ichnological evidence on the behaviour of mitrates: two trails associated with the Devonian mitrate Rhenocystis |url=https://www.scup.com/doi/10.1080/00241160050150267 |journal=Lethaia |language=en |volume=33 |issue=1 |pages=1–12 |doi=10.1080/00241160050150267 |issn=0024-1164}}</ref><ref name=Rahman2009>{{Cite journal |last=Rahman |first=Imran A. |last2=Jefferies |first2=Richard P. S. |last3=SüDkamp |first3=Wouter H. |last4=Smith |first4=Ru D. A. |date=January 2009 |title=Ichnological insights into mitrate palaeobiology |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2008.00838.x |journal=Palaeontology |language=en |volume=52 |issue=1 |pages=127–138 |doi=10.1111/j.1475-4983.2008.00838.x |issn=0031-0239}}</ref> Their interpretation requires an understanding of how the animal was oriented in life; it's not agreed whether the convex side of the head was up or down, or indeed whether the "tail" was at the front or back of the organism.<ref name=Gee2000>{{Cite journal |last=Gee |first=Henry |date=October 2000 |title=Mitrates on the move |url=https://www.nature.com/articles/35038193 |journal=Nature |language=en |volume=407 |issue=6806 |pages=849–851 |doi=10.1038/35038193 |issn=0028-0836}}</ref> The trace fossils suggest that they pulled themselves through the mud with their "tail", and were flat-side up.<ref name=Gee2000/>

== Taxa ==
The following taxa are recognized as being included in the Mitrata as of a 2002 review of the order:<ref name=Dominguez_et_al2002>{{Cite journal |last=Domínguez Alonso |first=Patricio |last2=Jefferies |first2=Richard P. S. |last3=Gil Cid |first3=María Dolores |date=December 2002 |title=An annotated check-list of genera and species of carpoids |url=https://hdl.handle.net/20.500.14352/56880 |journal=Coloquios de Palcontologia |volume=53 |pages=33-68 |issn=1132-1660}}</ref>

{{div col|colwidth=25em|small=yes}}
*''[Adoketocarpus](/source/Adoketocarpus)'' {{Small|Ruta & Jell, 1999}}
*''[Allanicytidium](/source/Allanicytidium)'' {{Small|Caster & Gill, 1967}}
*''[Anatifopsis](/source/Anatifopsis)'' {{Small|Barrande, 1872}}
*''[Anomalocystites](/source/Anomalocystites)'' {{Small|Hall, 1859}}
*''[Aspidocarpus](/source/Aspidocarpus)'' {{Small|Ubaghs, 1979}}
*''[Ateleocystites](/source/Ateleocystites)'' {{Small|Billings, 1858}}
*''[Australocystis](/source/Australocystis)'' {{Small|Caster, 1954}}
*''[Balanocystites](/source/Balanocystites)'' {{Small|Barrande, 1887}}
*''[Barrandeocarpus](/source/Barrandeocarpus)'' {{Small|Ubaghs, 1979}}
*''[Bokkeveldia](/source/Bokkeveldia)'' {{Small|Ruta & Theron, 1997}}
*''[Chauvelia](/source/Chauvelia)'' {{Small|Cripps, 1990}}
*''[Chinianocarpos](/source/Chinianocarpos)'' {{Small|Ubaghs, 1961}}
*''[Dalejocystis](/source/Dalejocystis)'' {{Small|Prokop, 1963}}
*''[Diamphidiocystis](/source/Diamphidiocystis)'' {{Small|Kolata & Guensburg, 1979}}
*''[Enoploura](/source/Enoploura)'' {{Small|Wetherby, 1879}}
*''[Eumitrocystella](/source/Eumitrocystella)'' {{Small|Beisswenger, 1994}}
*''[Guichenocarpos](/source/Guichenocarpos)'' {{Small|Chauvel, 1981}}
*''[Jaekelocarpus](/source/Jaekelocarpus)'' {{Small|Kolata, Frest & Mapes, 1991}}
*''[Kierocystis](/source/Kierocystis)'' {{Small|Parsley, 1991}}
*''[Kopficystis](/source/Kopficystis)'' {{Small|Parsley, 1991}}
*''[Lagynocystis](/source/Lagynocystis)'' {{Small|Jaekel, 1918}}
*''[Milonicystis](/source/Milonicystis)'' {{Small|Chauvel, 1986}}
*''[Mitrocystella](/source/Mitrocystella)'' {{Small|Jaekel, 1901}}
*''[Mitrocystites](/source/Mitrocystites)'' {{Small|Barrande, 1887}}
*''[Mongolocarpos](/source/Mongolocarpos)'' {{Small|Rozhnov, 1990}}
*''[Notocarpos](/source/Notocarpos)'' {{Small|Philip, 1981}}
*''[Occultocystis](/source/Occultocystis)'' {{Small|Haude, 1995}}
*''[Ovocarpus](/source/Ovocarpus)'' {{Small|Ubaghs, 1994}}
*''[Paranacystis](/source/Paranacystis)'' {{Small|Caster, 1954}}
*''[Peltocystis](/source/Peltocystis)'' {{Small|Thoral, 1935}}
*''[Placocystella](/source/Placocystella)'' {{Small|Rennie, 1936}}
*''[Placocystites](/source/Placocystites)'' {{Small|de Koninck, 1869}}
*''[Protocytidium](/source/Protocytidium)'' {{Small|Ruta & Jell, 1999}}
*''[Pseudovictoriacystis](/source/Pseudovictoriacystis)'' {{Small|Ruta & Jell, 1999}}
*''[Rhenocystis](/source/Rhenocystis)'' {{Small|Dehm, 1932}}
*''[Spermacystis](/source/Spermacystis)'' {{Small|Ubaghs, 1967}}
*''[Tasmanicytidium](/source/Tasmanicytidium)'' {{Small|Caster, 1983}}
*''[Victoriacystis](/source/Victoriacystis)'' {{Small|Gill & Caster, 1960}}
*''[Vizcainocarpus](/source/Vizcainocarpus)'' {{Small|Ruta, 1997}}
*''[Willmanocystis](/source/Willmanocystis)'' {{Small|Kolata & Jollie, 1982}}
*''[Yachalicystis](/source/Yachalicystis)'' {{Small|Haude, 1995}}
{{div col end}}

==References==
{{Reflist}}

{{Taxonbar|from=Q21447679}}

Category:Homalozoa

{{paleo-echinoderm-stub}}

---
Adapted from the Wikipedia article [Mitrate](https://en.wikipedia.org/wiki/Mitrate) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Mitrate?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.