Ottoia

{{Short description|Extinct genus of priapulid worms}} {{Automatic taxobox | fossil_range = {{Fossil range|Miaolingian|Furongian|refs=<ref name="Smith2015"/>|latest = Tremadocian | PS = (Floian ?) }} | image = Ottoia reconstruction.jpg | image_caption = Reconstruction of ''Ottoia prolifica''. | image2 = Ottoia prolifica NMNH 57622.jpg | image2_caption = The anterior portion of ''Ottoia prolifica'', illustrating annulation and the eversible proboscis. From Smith ''et al''. (2015)<ref>Smith MR, Harvey THP, Butterfield NJ(2015) Data from: The macro- and microfossil record of the middle Cambrian priapulid Ottoia. Dryad Digital Repository. {{doi|10.5061/dryad.km109}}</ref> | parent_authority = Walcott, 1911 | taxon = Ottoia | authority = Walcott, 1911 | subdivision_ranks = Species | subdivision = {{species list | O. prolifica | Walcott, 1911 (type) | O. tricuspida | Smith ''et al.'', 2015<ref name="Smith2015">{{Cite journal | doi = 10.1111/pala.12168| title = The macro- and microfossil record of the Cambrian priapulid ''Ottoia''| journal = Palaeontology| volume = 58| issue = 4| pages = 705–721| year = 2015| last1 = Smith | first1 = M. R. | last2 = Harvey | first2 = T. H. P. | last3 = Butterfield | first3 = N. J. | bibcode = 2015Palgy..58..705S| url = http://dro.dur.ac.uk/18218/1/18218.pdf| doi-access = free}}</ref> }} }}

'''''Ottoia''''' is a stem-group archaeopriapulid worm known from Cambrian fossils.<ref name=Budd2000>{{cite journal|last1=Budd |first1=G. E.|last2=Jensen |first2=S.|year=2000|title=A critical reappraisal of the fossil record of the bilaterian phyla|volume=75 |issue=2 |pages=253–95|journal=Biological Reviews of the Cambridge Philosophical Society|doi=10.1111/j.1469-185X.1999.tb00046.x|pmid=10881389|s2cid=39772232}}</ref> Although priapulid-like worms from various Cambrian deposits are often referred to ''Ottoia'' on spurious grounds, the only clear ''Ottoia'' macrofossils come from the Burgess Shale of British Columbia, which was deposited {{Ma|508}}.<ref name=Smith2015/> Microfossils extend the record of ''Ottoia'' throughout the Western Canada Sedimentary Basin, from the mid- to late Cambrian.<ref name=Smith2015/> A few fossil finds are also known from China.<ref>{{cite web |title=Miaobanpo section (Orytocephalus indicus zone) - Kaili Fm (Cambrian of China) |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=79770&is_real_user=1 |website=PBDB}}</ref>

== Morphology == thumb|left|Holotype specimen of ''Ottoia tricuspida'', from Smith ''et al''. 2015<ref name=Smith2015/> ''Ottoia'' specimens are on average 8 centimeters in length. Both length and width show variation with contraction; shorter specimens often being wider than longer ones. The characteristic proboscis of priapulids is present at the anterior, attached to the trunk of the animal, proceeded by the "bursa" at the posterior. The organism's body is bilaterally symmetrical, however, its anterior displays external radial symmetry. Like some other modern invertebrates, a cuticle restricts the size of and protects the animal.

The trunk holds the internal organs of the organism, divided into seventy to a hundred annulations of varying spacing, depending on curvature and contraction. The posterior displays a series of hooks, which likely acted as anchors during burrowing. Muscles support the animal and retract the bursa and proboscis. A gut leading from the anus in the bursa to the mouth in the proboscis runs through the trunk's spacious body cavity, and a concentration of gut muscles serve the function of a gizzard. A nerve chord runs down the organism's length. In addition to the other organs, it is possible ''Ottoia'' contained urogenital organs in its trunk. There is no evidence of a respiratory organ, though the bursa may have served this purpose.<ref name=SCM1977>{{Cite journal | author1 = Conway Morris, S | title = Fossil priapulid worms | journal = Special Papers in Palaeontology | volume = 20 | year = 1977 }}</ref>

thumb|left|Schematic diagrams of ''Ottoia'' sclerite morphologies.<ref name="Smith2015"/> Sclerites comprise a broad, flat basal pad and a thickened, usually triangular arch. Denticles arise from the lateral margins of the arch; distal extension of the arch gives rise to a prong. An oblique spur arises from the basal region. thumb|Teeth of ''Ottoia prolifica'', from Smith ''et al''. 2015<ref name=Smith2015/> The everted proboscis of ''Ottoia'' bears an armature of teeth and hooks. The detailed morphology of these elements distinguishes the two described species, ''O. tricuspida'' and ''O. prolifica''.<ref name=Smith2015/> At the base of the pharynx, separated from the teeth by an unarmed region, sits a ring of spines. Behind this, at the front of the trunk, lies a series of hooks and spines, arranged in a quincunx pattern like the five dots on a domino or dice.<ref name=Smith2015/>

== Ecology == [[File:Ottoia burrowing.jpg|thumb|A reconstruction of ''Ottoia'' burrowing in substrate, nearby a ''Haplophrentis''.]]

''Ottoia'' was a burrower that hunted prey with its eversible proboscis.<ref name=Vannier2009>{{Walcott2009|vannier-2}}</ref> It also appears to have scavenged on dead organisms such as the arthropod ''Sidneyia''.<ref name=Bruton2001>{{Cite journal| last1 = Bruton | first1 = D. L.| title = A death assemblage of priapulid worms from the Middle Cambrian Burgess Shale| journal = Lethaia| volume = 34| issue = 2| pages = 163–167| year = 2001| doi = 10.1080/00241160152418456| bibcode = 2001Letha..34..163B}}</ref>

The spines on the proboscis of ''Ottoia'' have been interpreted as teeth used to capture prey. Its mode of life is uncertain, but it is thought to have been an active burrower, moving through the sediment after prey, and is believed to have lived within a U-shaped burrow that it constructed in the substrate. From that place of relative safety, it could extend its proboscis in search of prey. Gut contents show that this worm was a predator, often feeding on the hyolithid ''Haplophrentis'' (a shelled animal similar to mollusks), generally swallowed them head-first. They also show evidence of cannibalism, which is common in priapulids today.

== Preservation ==

Because of its bottom-living habit and the location of the Burgess Shale site at the foot of a high limestone reef, one may presume the relative immobility of ''Ottoia'' placed it in danger of being carried away and/or buried by any underwater mud avalanche from the cliff top. This may explain why it remains one of the more abundant specimens of the Burgess Shale fauna.

== Distribution ==

At least 1000 Burgess Shale specimens are known in the UNSM collections alone,<ref name=SCM1977/> in addition to the ROM collections and hundreds of specimens elsewhere. 677 specimens of ''Ottoia'' are known from the Greater Phyllopod bed, where they comprise 1.29% of the community.<ref name=Caron2006>{{cite journal|last1=Caron |first1=Jean-Bernard|last2=Jackson |first2=Donald A.|title=Taphonomy of the Greater Phyllopod Bed community, Burgess Shale|journal=PALAIOS |volume=21 |issue=5 |pages=451–65|date=October 2006|doi=10.2110/palo.2003.P05-070R|jstor=20173022|bibcode=2006Palai..21..451C |s2cid=53646959 }}</ref>

''Ottoia'' has also been reported from Middle Cambrian deposits in Utah and Spain,<ref name=SCM1986>{{cite journal | last1 = Conway Morris | first1 = S. | last2 = Robison | first2 = R. A. | year = 1986 | title = Middle Cambrian priapulids and other soft-bodied fossils from Utah and Spain | url = http://kuscholarworks.ku.edu/dspace/bitstream/1808/3696/1/paleo.paper.117.pdf | journal = University of Kansas Paleontological Contributions | volume = 117 | pages = 1–22 | hdl =1808/3696}}</ref> Nevada,<ref>{{Cite journal| last1 = Lieberman | first1 = B. S.| title = A New Soft-Bodied Fauna: the Pioche Formation of Nevada| journal = Journal of Paleontology| volume = 77| issue = 4| pages = 674–690| year = 2003| issn = 0022-3360| doi = 10.1666/0022-3360(2003)077<0674:ANSFTP>2.0.CO;2| bibcode = 2003JPal...77..674L}}</ref> and various other localities.<ref>Supplementary Information used to be available in: {{doi|10.13140/RG.2.1.3052.4328}}</ref> Nevertheless, these reports are insecure, and the only verifiable ''Ottoia'' macrofossils herald from the Burgess Shale itself.<ref name=Smith2015/>

Microfossils corresponding to ''Ottoia'' teeth, however, have a much broader distribution, and are found throughout the Western Canada Sedimentary Basin.<ref name=Smith2015/> Indeed, putative candidates (initially described under the ICBN as ''Goniomorpha'') may extend the range of ''Ottoia'', or at least similar priapulans, into the Ordovician.<ref>{{Cite journal | doi =10.1080/01916122.2022.2157504| title =Palynological recovery of small carbonaceous fossils (SCFS) indicates that the late Cambrian acritarch Goniomorpha Yin 1986 represents the teeth of a priapulid worm| year =2023| last1 =Shan| first1 =Longlong| last2 =Harvey| first2 =Thomas H.P.| last3 =Yan| first3 =Kui| last4 =Li| first4 =Jun| last5 =Zhang| first5 =Yuandong| last6 =Servais| first6 =Thomas| journal =Palynology| volume =47| issue =3| article-number =2157504| bibcode =2023Paly...4757504S| s2cid =254711455}}</ref> One poorly preserved specimen that probably belongs to ''Ottoia'', was discovered in the Lower Ordovician Madaoyu Formation in Hunan, China.<ref name=Fang2022>{{cite journal|author=Xiang Fang, Yingyan Mao, Qi Liu, Wenwei Yuan, Zhongyang Chen, Rongchang Wu, Lixia Li, Yuchen Zhang, Junye Ma, Wenhui Wang, Renbin Zhan, Shanchi Peng, Yuandong Zhang, Diying Huang|year=2022|url=https://www.researchgate.net/publication/361971078|title=The Liexi fauna: a new Lagerstätte from the Lower Ordovician of South China|journal=Proceedings of the Royal Society B|volume=289|issue=1978|page=1—8|doi=10.1098/rspb.2022.1027|pmid=35858062 |language=en|pmc=9277276}}</ref>

== See also == *Paleobiota of the Burgess Shale ==References==

== External links ==

* {{Cite web|date=2011|title=''Ottoia prolifica''|work=Burgess Shale Fossil Gallery|publisher=Virtual Museum of Canada|url=http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=95|archive-url=https://web.archive.org/web/20201112025257/http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=95|archive-date=2020-11-12|url-status=dead|access-date=2023-01-21}} *[http://paleobiology.si.edu/burgess/ottoia.html ''Ottoia prolifica'' (A priapulid worm) from the Smithsonian Institution.] *[https://park.org/Canada/Museum/burgessshale/worms.html ''Ottoia prolifica'' from the Hooper Virtual Paleontological Museum (HVPM)]

Category:Prehistoric protostome genera Category:Burgess Shale fossils Category:Cambrian invertebrates Category:Priapulida Category:Miaolingian first appearances Category:Furongian extinctions Category:Fossil taxa described in 1911 Category:Wheeler Shale Category:Cambrian genus extinctions