{{Short description|Extinct order of cnidarians}} {{Automatic taxobox | taxon = Conulariida | authority = Miller and Gurley, 1896 | fossil_range = Late Ediacaran-late Triassic, {{fossil range|545|205}} | image = Conulariid03.jpg | image_caption = Conulariid from the Mississippian (c. 360 to 325 mya) of Indiana; scale in mm. | image2 = Conularia gratiosa (fossil conulariids) (Salem Limestone, Middle Mississippian; Spergen Hill, Indiana, USA) 3.jpg | image2_caption = Two ''Conularia gratiosa'' specimens from the Salem Limestone aged to the Middle Mississippian. | subdivision_ranks = Genera | subdivision = See text. }}
'''Conulariida''' are an extinct group of medusozoan cnidarians known from fossils spanning from the latest Ediacaran up until the Late Triassic.<ref>{{Cite book|chapter-url=http://insugeo.org.ar/publicaciones/docs/scg_17/43.htm |chapter=Study of conulariid and related phosphatic conical exoskeletons from the Prague Basin (Czech Republic)|title=Ordovician from the Andes |author1=Ben M. Waggoner |author2=David Smith |date=1994|publisher=INSTITUTO SUPERIOR DE CORRELACIÓN GEOLÓGICA|series=Serie Correlación Geológica Nº 17|editor=G. L. Albanesi |editor2=M. S. Beresi |editor3=S. H. Peralta}}</ref><ref name=":0">{{cite journal |last1=Leme |first1=J. M. |last2=Van Iten |first2=H. |last3=Simões |first3=M. G. |year=2022 |title=A New Conulariid (Cnidaria, Scyphozoa) From the Terminal Ediacaran of Brazil |journal=Frontiers in Earth Science |volume=10 |article-number=777746 |bibcode=2022FrEaS..10.7746L |doi=10.3389/feart.2022.777746 |doi-access=free}}</ref><ref name=":1">{{Cite journal |last1=Van Iten |first1=Heyo |last2=Hughes |first2=Nigel C. |last3=John |first3=Douglas L. |last4=Gaines |first4=Robert R. |last5=Colbert |first5=Matthew W. |date=2023-04-27 |title=Conulariid soft parts replicated in silica from the Scotch Grove Formation (lower Middle Silurian) of east-central Iowa |journal=Journal of Paleontology |volume=97 |issue=5 |language=en |pages=961–970 |doi=10.1017/jpa.2023.6 |s2cid=258389436 |issn=0022-3360|doi-access=free }}</ref> They are almost exclusively known from their hard external structures (alternatively referred to as a theca, periderm or test), which were pyramidal in shape and made up of numerous lamellae (thin layers). They are thought to have been sessile animals that grew with the narrower tip anchored to the seafloor, with the wider end bearing an array of tentacles used to ensnare prey.
==Structure== The conulariids are fossils preserved as shell-like structures made up of rows of calcium phosphate rods, resembling an ice-cream cone with fourfold symmetry, usually four prominently-grooved corners.<ref>Waggoner, B.M. & D. Smith (1994): The Conulariida, Mystery fossils. University of California Museum of Paleontology web page [http://www.ucmp.berkeley.edu/cnidaria/conulariida.html]</ref> New rods were added as the organism grew in length; the rod-based growth falsely gives the fossils a segmented appearance. Exceptional soft-part preservation has revealed that soft tentacles protruded from the wider end of the cone, and a holdfast from the pointed end attached the organisms to hard substrate. The prevailing reconstruction of the organism has it look superficially like a sea anemone sitting inside an angular, hard cone held perpendicular to the substrate. Conulariid shell is composed of francolite with carbonate ion concentration 8.1 wt%. The lattice parameters of conulariid apatite are a = 9.315(7) Å, c = 6.888(3) Å.<ref name='VinnKirsimae2015'>{{cite journal | doi = 10.4202/app.00049.2013 | title = Alleged cnidarian ''Sphenothallus'' in the Late Ordovician of Baltica, its mineral composition and microstructure | year = 2015 | author = Vinn, O. | author2 = Kirsimäe, K. | journal = Acta Palaeontologica Polonica | volume = 60 | pages = 1001–1008 | doi-access = free}}</ref> The fine structure of their shell comprises multiple lamellae of alternately organic-rich and organic-poor layers.<ref>{{cite journal|doi=10.1017/jpa.2016.63|title=Microstructure and composition of the periderm of conulariids|journal=Journal of Paleontology|volume=90|issue=3|pages=389|year=2016|last1=Ford|first1=Robert C.|last2=Van Iten|first2=Heyo|last3=Clark|first3=George R.|s2cid=133541791}}</ref>
==Fossil record== thumb|Close-up of a conulariid from the Mississippian of Indiana; scale in mm.|left [[Image:Conularia milwaukeensis.jpg|thumb|Conularia milwaukeensis from the Middle Devonian of Wisconsin.|left]] [[File:UWGM 2723---Conularia niagarensis.jpg|thumb|A pair of ''Conularia niagarensis'' specimens from the Lower Silurian Waukesha Biota site in Wisconsin.]] With the inclusion of the possible Ediacaran conulariid ''Vendoconularia'', which may or may not be a conulariid at all,<ref>{{Cite journal| last1 = Van Iten| last4= Guimaraes Simoes | first1 = H.| last3=Coelho Rodrigues| last2=De Moraes Leme| first2 = J. | first3 = S. | first4 = M.| title = Reinterpretation of a Conulariid-Like Fossil from the Vendian of Russia| journal = Palaeontology| volume = 48| issue = 3| pages = 619–622| year = 2005| doi = 10.1111/j.1475-4983.2005.00471.x| hdl= 11449/31655 | s2cid= 247733826 | hdl-access = free}}</ref> and the definite late Ediacaran conulariid ''Paraconularia ediacara'',<ref name=":0" /> the '''Conulata''' fossil record begins with undeniable specimens in the Upper Ediacaran and extends without significant break through numerous major mass extinctions. The Conulariids finally disappear from the fossil record during the Late Triassic, by which time they were very rare, with only 8 documented occurrences across the entire Triassic. Their extinction may have been due to the rise of durophagous organisms as part of the Mesozoic marine revolution.<ref>{{Cite journal |last=Lucas |first=Spencer G. |date=2012-03-22 |title=The Extinction of the Conulariids |journal=Geosciences |language=en |volume=2 |issue=1 |pages=1–10 |doi=10.3390/geosciences2010001 |issn=2076-3263 |doi-access=free }}</ref>
In North America, conulariids are generally more common in rocks of Ordovician and Carboniferous age.
==Lifestyle== thumb|Life restoration of a conulariid, showing the soft-bodied anatomy Conulariids were benthic animals that were sessile and attached to a substrate at the base of the theca, older individuals may have become recumbent (tipped over).<ref>{{Citation |last1=Iten |first1=Heyo Van |title=14. Conulariids |date=2004-12-31 |url=https://www.degruyter.com/document/doi/10.7312/webb12678-015/html |work=The Great Ordovician Biodiversification Event |pages=119–123 |editor-last=Webby |editor-first=Barry D. |access-date=2023-06-25 |publisher=Columbia University Press |doi=10.7312/webb12678-015 |isbn=978-0-231-12678-6 |last2=Vyhlasová |first2=Zdenka |editor2-last=Paris |editor2-first=Florentin |editor3-last=Droser |editor3-first=Mary L. |editor4-last=Percival |editor4-first=Ian G.|url-access=subscription }}</ref> They are generally proposed to have been predators, using tentacles to ensnare prey.<ref>{{Cite journal |last1=Leme |first1=Juliana M. |last2=Van Iten |first2=Heyo |last3=Simões |first3=Marcello G. |date=2022-06-08 |title=A New Conulariid (Cnidaria, Scyphozoa) From the Terminal Ediacaran of Brazil |journal=Frontiers in Earth Science |volume=10 |doi=10.3389/feart.2022.777746 |bibcode=2022FrEaS..10.7746L |issn=2296-6463 |doi-access=free }}</ref>
==Phylogeny== About 20 genera and 150 species are known,<ref>{{cite web |url=http://www.zoobank.org/advancedquery.htm?searchType=tree&pp=10&so=a0&q=Conulariida |title=ZooBank: The World Register of Animal Names |website=www.zoobank.org |access-date=14 January 2022 |archive-url=https://web.archive.org/web/20070927222951/http://www.zoobank.org/advancedquery.htm?searchType=tree&pp=10&so=a0&q=Conulariida |archive-date=27 September 2007 |url-status=dead}}</ref> but except for local occurrences, conulariids are relatively uncommon.
The conulariids were originally thought to be anthozoan cnidarians. However, the lack of septa or other features diagnostic of anthozoans led researchers to abandon this hypothesis. Ivantsov and Fedonkin (2002) posit that the conulariids were ancestrally tri-radially symmetrical, as typified with ''Vendoconularia'', typical of the structure seen in vendozoans.<ref>{{Cite journal| first1 = A. Y.| last2 = Fedonkin| first2 = M. A.| last1 = Ivantsov| title = Conulariid-like fossil from the Vendian of Russia: a metazoan clade across the Proterozoic/Palaeozoic boundary| journal = Palaeontology| volume = 45| issue = 6| pages = 1119–1129| year = 2002| doi = 10.1111/1475-4983.00283| doi-access = free}}</ref> Conulariids are, however, technically a part of the Ediacaran biota as their fossil record starts at latest parts of that period.<ref name=":0" />
It is now also thought that the conulate trilobozoans derived their fourfold symmetry from a sixfold symmetry, as seen in ''Vendoconularia''. This in turn, is thought to be originally derived from an ancestral disk-like trilobozoan three-fold symmetry.{{citation needed|date=January 2024}}
Until the 1930s, the affinities of conulariids were unknown.<ref>{{Cite journal |last=Slater |first=Ida L. |date=1907 |title=A monograph of British Conulariae |url=https://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/year/2007/docId/17490 |journal=Monographs of the Palaeontographical Society |volume=6 |pages=1–41}}</ref> They were first proposed to be fossil scyphozoans by Helmut Kiderlen.<ref>{{Cite journal |last=Kiderlen |first=Helmut |date=1937 |title=Die Conularien. Über Bau und Leben der ersten Scyphozoa |journal=Neues Jahrbuch für Mineralogie, Geologie und Paläontologie |volume=Beilage-Band 77 (B) |pages=113–169}}</ref> Since then conulariids have generally been thought to be of Cnidarian affinity, either near the base of the cnidarian family tree or members of the subclade Medusozoa, though their exact placement within the clade is still uncertain.<ref name=":1" />
==Pearls== Conulariids produced pearls within their shells, similar to the way molluscs such as oysters, other bivalves, and some gastropods do today. These pearls give a clue as to the internal anatomy of the conulariid animal. But due to their calcium phosphate composition, their crystal structure, and their extreme age, these pearls tend to be rather unattractive for use in or as decorative objects.<ref>{{cite book | url=https://books.google.com/books?id=wFPgBAAAQBAJ&q=Conulariid+pearls | title=Evolutionary Paleobiology of Behavior and Coevolution | publisher=Elsevier | author=Boucot, A.J. | year=2013 | pages=750 (page 69) | isbn=9781483290812}}</ref>
==List of genera== {{div col|colwidth=24em}} *''Aciconularia'' *''Adesmoconularia'' *''Anaconularia'' *''Archaeoconularia'' *''Australoconularia'' *''Barbigodithreca'' *''Calloconularia'' *''Circonularia'' *''Climacoconus'' *''Conchopeltis'' *''Conomedusites''? *''Conulariella'' *''Conularia'' *''Conularina'' *''Conulariopsis'' *''Ctenoconularia'' *''Diconularia'' *''Eoconularia'' *''Exoconularia'' *''Flectoconularia'' *''Garraconularia'' *''Glyptoconularia'' *''Gondaconularia'' *''Hexangulaconularia'' *''Holoconularia'' *''Mabianoconullus'' *''Mesoconularia'' *''Metaconularia'' *''Neoconularia'' *''Notoconularia'' *''Palaenigma'' *''Paraconularia'' *''Pseudoconularia'' *''Quadrosiphogonuchites'' *''Reticulaconularia'' *''Tasmanoconularia'' *''Vendoconularia'' {{Div col end}}
==References== {{Reflist}}
=== Bibliography === * {{cite journal|last1=Babcock |first1=L. E. |author2=Feldmann, R. М. |year=1986 |title=Devonian and Mississippian conulariids of North America. Part A. General description and Conularia |journal=Annals of Carnegie Museum |volume=55 |pages=349–410 |doi=10.5962/p.215203 |s2cid=251529155 |doi-access=free}} * {{cite book |last=Babcock |first=L. E. |year=1991 |chapter=The enigma of conulariid affinities |pages=133–143 |editor1=A. M. Simonetta |editor2=S. Conway Morris |editor2-link=Simon Conway Morris |title=The Early Evolution of Metazoa and the Significance of Problematic Taxa |publisher=Cambridge University Press |location=Cambridge}} * {{cite journal |author=Hughes, N. C. |author2=Gunderson, G. D. |author3=Weedon, M. J. |year=2000 |title=Late Cambrian conulariids from Wisconsin and Minnesota |journal=Journal of Paleontology |volume=74 |issue=5 |pages=828–838 |doi=10.1666/0022-3360(2000)074<0828:lccfwa>2.0.co;2 |s2cid=130269674 }} * {{cite book |last=Van Iten |first=H. |year=1991|chapter=Evolutionary affinities of conulariids |pages=145–155 |editor1=A. M. Simonetta |editor2=S. Conway Morris |title=The Early Evolution of Metazoa and the Significance of Problematic Taxa |publisher=Cambridge University Press |location=Cambridge}}
==External links== *{{Cite web|url=http://www.ucmp.berkeley.edu/cnidaria/conulariida.html|title=The Conulariida: Mystery fossils|author1=Zdenka Brabcova |author2=Petr Kraft |date= 2003-06-15|accessdate=2008-02-04}} *http://www.uga.edu/strata/cincy/fauna/conulariida/Conularia.html
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Category:Staurozoa Category:Prehistoric cnidarians Category:Early Triassic extinctions Category:Cambrian genus extinctions Category:Ediacaran first appearances