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Ixat totep (talk | contribs) It's a clade now, we can capitalize it and use the formal name in the lede |
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| subdivision = *''[[Herpetogaster]]''
*''[[Phlogites]]''
*[[Eldonioidea]]
}}
The '''
==Description==
One leading hypothesis is that cambroernids were unusual [[Ambulacraria|ambulacrarian]] [[Deuterostome|deuterostomes]], related to [[Echinoderm|echinoderms]] and [[Hemichordate|hemichordates]].<ref name="Caron2010" /> Previously some cambroernids were compared to members of the broad invertebrate clade [[Lophotrochozoa]]; in particularly they were allied with [[Lophophore|lophophorates]], a subset of lophotrochozoans bearing [[Cilium|ciliated]] tentacles known as [[Lophophore|lophophores]].<ref name=":2">{{Cite journal |last1=Dzik |first1=Jerzy |last2=Yuanlong |first2=Zhao |last3=Maoyan |first3=Zhu |date=1997 |title=Mode of life of the Middle Cambrian eldonioid lophophorate ''Rotadiscus'' |url=https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_40/vol40_part2_pp385-396.pdf |journal=Palaeontology |volume=40 |issue=2 |pages=385–396}}</ref> However, this interpretation has more recently been considered unlikely relative to the deuterostome hypothesis for cambroernid origins.<ref name="Caron2010" />▼
Cambroernids encompass three particular types of enigmatic animals first appearing in the Cambrian: ''[[Herpetogaster]]'' (the [[type genus]]), ''[[Phlogites]]'', and the [[Eldonioidea]]. They are united by a set of common features including at least one pair of bifurcated or divided oral tentacles, and a large stomach and narrower intestine enclosed together in a clockwise-coiled sac.<ref name="Caron2010" />
==Phylogeny==
Phylogenetic analysis offers strong support for Cambroernida as a clade of stem-group ambulacrarians.<ref name=analysis>{{harvnb|Li|Dunn|Murdock|Guo|2023|page=2362}}</ref> The following cladogram is simpllified from Li ''et al.'' 2023; only a sampling of eldonioids were included in the analysis:<ref>{{harvnb|Li|Dunn|Murdock|Guo|2023|page=2363}}</ref>
{{Clade
|label1=[[Ambulacraria]]
==List of genera==▼
|sublabel1={{small|([[total group]])}}
|1={{Clade
|label1='''Cambroernida'''
|1={{Clade
|1=''[[Herpetogaster]]''
|2={{Clade
|1=''[[Phlogites]]''
|label2=[[Eldonioidea]]
|2={{Clade
|label1=[[Rotadiscidae]]
|1=''[[Rotadiscus]]''
|label2=[[Eldoniidae]]
|2={{Clade
|1=''Eldonia eumorpha''
|2=''Eldonia ludwigi''
|3=''[[Pararotadiscus]]''
}}
}}
}}
}}
|label2=[[Ambulacraria]]
|sublabel2={{small|([[crown group]])}}
|2={{Clade
|1=[[Hemichordata]]
|2=[[Echinodermata]]
}}
}}
}}
===Evolutionary history and significance===
{{multiple image|align=left|total_width=250
|header=From left: ''Herpetogaster collinsi'', ''Phlogites longus'', ''Eldonia ludwigi''
|image1=Diagram of Herpetogaster collinsi.png
|image2=Diagram of Phlogites longus.png
|image3=Diagram of Eldonia ludwigi.png
|footer=te: tentacles, ph: pharynx, dt: digestive tract, ics: inner coiled sac, ocs: outer coiled sac, an: anus, st: stolon
}}
Body coiling increased throughout this group's evolution.<ref name=analysis /> ''Herpetogaster'' has a segmented and clockwise-curved body attached to the substrate via a narrow and partially mobile [[stolon]] (stalk). ''Phlogites'' was even more simple, with a thick immobile stolon leading up to a tentacle-bearing calyx (cup-shaped main body). The eldoniids<ref name="Caron2010" /><ref name="Zhu2002">{{harvnb|Zhu|Zhao|Chen|2002}}</ref> (also known as eldonioids<ref name="Dzik1997" /><ref name="Lefebvre2022">{{harvnb|Lefebvre|Van Roy|Zamora|Gutiérrez-Marco|Nohejlová|2022}}</ref><ref name="Chen1995">{{harvnb|Chen|Zhu|Zhou|1995}}</ref> or eldonids<ref name="Hagadorn2019">{{harvnb|Hagadorn|Allmon|2019}}</ref><ref name="Lefebvre2022" />) were diverse and disc-shaped, commonly described as "medusiform", i.e. [[jellyfish]]-shaped. Though the lifestyle of eldoniids is still debated, it can be agreed that they had a large curved stomach and no stolon.<ref name="Dzik1997" /><ref>{{harvnb|Caron|Conway Morris|Shu|Soares|2010|page=7}}</ref><ref name="MacGabhann2010">{{harvnb|MacGabhann|Murray|2010}}</ref><ref name="Lefebvre2022" />
The lack of a post-anal tail in cambroernids suggests that, contrary to long-held assumptions, this feature was not present in the common ancestor of deuterostomes. This is congruent with the significant differences between the post-anal tails of [[chordates]] and [[hemichordates]]. This and other features of cambroernids suggest that post-anal tails, gill bars, and a U-shaped gut evolved multiple times in the deuterostomes through convergence.<ref name=characteristics>{{harvnb|Li|Dunn|Murdock|Guo|2023|pages=2362–2364}}</ref>
Segmentation, as seen in ''Herpetogaster'', is a notable characteristic of [[chordates]] not seen in other ambulacrarians, indicating that it might be a trait of ancestral deuterostomes.<ref name=characteristics />
{{clear|left}}
▲===List of genera===
*''[[Herpetogaster]]''
*''[[Phlogites]]''
*
**''[[
**''[[
**''[[
**''[[
**''[[
**''[[
**''[[Seputus]]''
* Unnamed Eldoniid▼
**''[[
**''[[Discophyllum]]''?
▲** Unnamed Eldoniid
===History of identification===
▲
==References==
{{Reflist}}
===Works cited===
{{refbegin}}
* {{Cite journal |last1=Chen |first1=Jun-yuan |last2=Zhu |first2=Mao-yan |last3=Zhou |first3=Gui-qing |date=1995 |title=The Early Cambrian medusiform metazoan ''Eldonia'' from the Chenjiang Lagerstätte |url=https://www.app.pan.pl/archive/published/app40/app40-213.pdf |journal=Acta Palaeontologica Polonica |volume=40 |issue=3 |pages=213–244}}
* {{Cite journal |last1=Caron |first1=J. |last2=Conway Morris |first2=S. |last3=Shu |first3=D. |last4=Soares |first4=D. |year=2010 |editor1-last=Soares |editor1-first=Daphne |title=Tentaculate fossils from the Cambrian of Canada (British Columbia) and China (Yunnan) interpreted as primitive deuterostomes |journal=PLOS ONE |volume=5 |issue=3 |pages=e9586 |bibcode=2010PLoSO...5.9586C |doi=10.1371/journal.pone.0009586 |pmc=2833208 |pmid=20221405 |doi-access=free}}
* {{Cite journal |last1=Dzik |first1=Jerzy |last2=Yuanlong |first2=Zhao |last3=Maoyan |first3=Zhu |date=1997 |title=Mode of life of the Middle Cambrian eldonioid lophophorate ''Rotadiscus'' |url=https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_40/vol40_part2_pp385-396.pdf |journal=Palaeontology |volume=40 |issue=2 |pages=385–396}}
* {{Cite journal |last1=Hagadorn |first1=James W. |last2=Allmon |first2=Warren D. |date=2019-01-01 |title=Paleobiology of a three-dimensionally preserved paropsonemid from the Devonian of New York |url=https://www.sciencedirect.com/science/article/pii/S0031018218305844 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |series=Studies in Honor of Prof. David J. Bottjer |language=en |volume=513 |pages=208–214 |doi=10.1016/j.palaeo.2018.08.007 |bibcode=2019PPP...513..208H |s2cid=133683311 |issn=0031-0182}}
* {{Cite journal |last1=Lefebvre |first1=Bertrand |last2=Van Roy |first2=Peter |last3=Zamora |first3=Samuel |last4=Gutiérrez-Marco |first4=Juan Carlos |last5=Nohejlová |first5=Martina |date=2022-03-31 |title=The Late Ordovician Tafilalt Biota, Anti-Atlas, Morocco: a high-latitude perspective on the GOBE |url=http://dx.doi.org/10.1144/sp485-2022-29 |journal=Geological Society, London, Special Publications |volume=485 |issue=1 |pages=5–35 |doi=10.1144/sp485-2022-29 |bibcode=2022GSLSP.485....5L |s2cid=247351043 |issn=0305-8719}}
* {{Cite journal |last1=MacGabhann |first1=Breandán Anraoi |last2=Murray |first2=John |date=2010 |title=Non-mineralised discoidal fossils from the Ordovician Bardahessiagh Formation, Co. Tyrone, Ireland |journal=Irish Journal of Earth Sciences |volume=28 |pages=1–12 |doi=10.3318/IJES.2010.28.1 |jstor=25780702 |hdl-access=free |hdl=10395/2407|s2cid=129593969 }}
* {{cite journal |last1=Li |first1=Yujing |last2=Dunn |first2=Frances S. |last3=Murdock |first3=Duncan J.E. |last4=Guo |first4=Jin |last5=Rahman |first5=Imran A. |last6=Cong |first6=Peiyun |title=Cambrian stem-group ambulacrarians and the nature of the ancestral deuterostome |journal=Current Biology |date=May 10, 2023 |doi=10.1016/j.cub.2023.04.048 |pmid=37167976 |s2cid=258592223 |url=https://doi.org/10.1016/j.cub.2023.04.048 |access-date=11 May 2023|doi-access=free }}
* {{Cite journal |last1=Zhu |first1=Mao-Yan |last2=Zhao |first2=Yuan-Long |last3=Chen |first3=Jun-Yuan |date=2002-03-01 |title=Revision of the Cambrian discoidal animals Stellostomites eumorphus and Pararotadiscus guizhouensis from South China |url=https://www.sciencedirect.com/science/article/pii/S0016699502000256 |journal=Geobios |language=en |volume=35 |issue=2 |pages=165–185 |doi=10.1016/S0016-6995(02)00025-6 |bibcode=2002Geobi..35..165Z |issn=0016-6995}}
{{refend}}
{{Taxonbar|from=Q5025672}}
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