{{Short description|Species of Ediacaran cnidarian}} {{Speciesbox | fossil_range = Late Ediacaran, {{fossil range|560}} | image = Haootia reconstruction 2024.jpg | image_caption = Life restoration from McIlroy ''et al.'', 2024 | genus = Haootia | parent_authority = Liu ''et al.'', 2014 | species = quadriformis | authority = Liu ''et al.'', 2014 }}
'''''Haootia quadriformis''''' is an extinct animal belonging to the Ediacaran biota. Estimated to be about 560 million years old, ''H. quadriformis'' is identified as a cnidarian polyp, and represents the earliest known evidence for muscle tissue in an animal.<ref name=daily>{{cite news|title=Animals first flex their muscles: Earliest fossil evidence for animals with muscles|url=https://www.sciencedaily.com/releases/2014/08/140826205417.htm|access-date=31 August 2014|work=ScienceDaily|date=26 August 2014}}</ref> Discovered in 2008 from Newfoundland in eastern Canada, it was formally described in 2014. It is the first Ediacaran organism discovered to show fossils of muscle fibres. Structural examination of the muscles and morphology indicate that the animal is a cnidarian, though, which class ''H. quadriformis'' belongs to was undetermined<ref>{{cite web|title=Animals first flex their muscles|url=http://www.pressreleasepoint.com/animals-first-flex-their-muscles|work=PressReleasePoint|publisher=University Of Cambridge|access-date=31 August 2014|date=27 August 2014}}</ref><ref name=liu>{{cite journal|last1=Liu|first1=A. G.|last2=Matthews|first2=J. J.|last3=Menon|first3=L. R.|last4=McIlroy|first4=D.|last5=Brasier|first5=M. D.|title=Haootia quadriformis n. gen., n. sp., interpreted as a muscular cnidarian impression from the Late Ediacaran period (approx. 560 Ma)|journal=Proceedings of the Royal Society B: Biological Sciences|year=2014|volume=281|issue=1793|article-number=20141202|doi=10.1098/rspb.2014.1202|pmid=25165764|pmc=4173675}}</ref> until a 2024 study found it to be a staurozoan.<ref name=mcilroy>{{cite journal |last1=McIlroy |first1=D. |last2=Pasinetti |first2=G. |last3=Pérez-Pinedo |first3=D. |last4=McKean |first4=C. |last5=Dufour |first5=S. C. |last6=Matthews |first6=J. J. |last7=Menon |first7=L. R. |last8=Nicholls |first8=R. |last9=Taylor |first9=R. S. |title=The Palaeobiology of Two Crown Group Cnidarians: Haootia quadriformis and Mamsetia manunis gen. et sp. nov. from the Ediacaran of Newfoundland, Canada |journal=Life |date=September 2024 |volume=14 |issue=9 |page=1096 |doi=10.3390/life14091096 |doi-access=free |language=en |issn=2075-1729|pmc=11432848 }}</ref>
== Discovery and name ==
The first fossil of ''Haootia'' was discovered from lower Fermeuse Formation of Back Cove, Bonavista Peninsula in Newfoundland. It was originally unearthed by Martin D. Brasier of the University of Oxford in 2008. However, the specimen was not allowed to be removed according to provincial law in Newfoundland, so that only a plaster cast was made. The cast (plastotype) is maintained in the collections of the Oxford University Museum of Natural History. The actual fossil specimen, or holotype, remains on the north shore of Back Cove, roughly {{cvt|1.8|km}} north-northwest of Melrose town. A second, incomplete specimen was also discovered in the Trepassey Formation of Burnt Point, Bonavista Peninsula.
The generic name ''Haootia'' is derived from the Beothuk word {{lang|bue|Haoot}}, meaning 'demon', to signify the striking appearance of the holotype. The specific name ''quadriformis'' is said to be derived from Latin {{lang|la|quadri}}, meaning 'fourfold', and {{lang|la|formis}}, for 'form', relating to the quadrilateral symmetry of the body.<ref name=liu/> The proper word in classical Latin for 'fourfold' is actually {{lang|la|quadruplex}},<ref name="Lewis & Short">Lewis, C.T. & Short, C. (1879). ''A Latin dictionary founded on Andrews' edition of Freund's Latin dictionary.'' Oxford: Clarendon Press.</ref> while {{lang|la|forma}} is the proper word in classical Latin for 'form'.<ref name="Lewis & Short" />
== Description ==
''Haootia quadriformis'' is uniquely different from any other Ediacaran fossil so far discovered in that it consists of bundles of fibres that have been identified as muscles. The entire body is in a broadly four-fold symmetrical arrangement. Thus the overall body organisation conforms to the key features of modern cnidarians.<ref name=daily/> The fossil measures 56×37 mm in diameter. It indicates it is a soft-bodied animal having an appearance of a smooth discoidal structure connected by a relatively short stem to a quadrate body comprising numerous and regularly aligned linear fibres. The fibres, which are similar in pattern to parallelly arranged muscle fibres, extend laterally across the body, linking adjacent corners. The fibres extend beyond each corner to form an elongate branch, which is divided into smaller dichotomous branches. Smaller branches also arise from the lateral margins of the quadrate body, and also form dichotomously branched fibres.<ref name=liu/>
==See also== * List of Ediacaran genera
== References ==
{{Reflist}}
== External links == *[http://www.sci-news.com/paleontology/science-haootia-quadriformis-fossil-earliest-evidence-muscles-02120.html 560-Million-Year-Old Fossil Provides Earliest Evidence of Muscles] *[http://www.upi.com/Science_News/2014/08/27/Newfoundland-fossil-is-earliest-evidence-of-muscled-animals/3361409146975/ Newfoundland fossil is earliest evidence of muscled animals] *[http://phys.org/news/2014-08-animals-flex-muscles.html Animals first flex their muscles] *[http://www.techtimes.com/articles/14208/20140828/haootia-quadriformis-muscle-fossil-newfoundland-cambrian-explosion.htm Newfoundland fossil is oldest with muscles]
{{Taxonbar|from=Q18164962|from2=Q129553420}}
Category:Monotypic prehistoric cnidarian genera Category:Ediacaran life Category:Ediacaran Newfoundland and Labrador Category:Fossils of Canada Category:Fossil taxa described in 2014 Category:Paleontology in Newfoundland and Labrador