Wikipedia

Cambroernid

The Cambroernida are a clade of unusual Paleozoic animals with coiled bodies and filamentous tentacles. They include a number of early to middle Paleozoic (Cambrian to Devonian)[1] genera noted as "bizarre" or "orphan" taxa, meaning that their affinities with other animals, living or extinct, have long been uncertain. While initially defined as an "informal stem group,"[2] later work with better-preserved fossils has strengthened the argument for Cambroernida as a monophyletic clade.[3]

Cambroernids
Temporal range: Cambrian–Devonian
Herpetogaster
Eldonia
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Stem group: Ambulacraria
Clade: †Cambroernida
Caron, Conway Morris, & Shu, 2010
Subdivisions

Description

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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.[2]

Taxonomy and evolution

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From left: Herpetogaster collinsi, Phlogites longus, Eldonia ludwigi
 
 
 
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.[4] 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), with internal gut coiling. The eldoniids[2][5] (also known as eldonioids[6][7][8] or eldonids[1][7]) 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.[6][9][10][7]

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.[11]

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.[11]

Phylogeny

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Phylogenetic analysis offers strong support for Cambroernida as a clade of stem-group ambulacrarians.[4] The following cladogram is simpllified from Li et al. 2023; only a sampling of eldonioids were included in the analysis:[12]

Ambulacraria
(total group)

Internal classification

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Genera whose family placement is tentative are preceded with (?).

Note that some authors continue to treat Stellostomites as a separate taxon.[14]

History of identification

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Previously, some cambroernids were compared to members of the broad invertebrate clade Lophotrochozoa. In particularl, they were allied with the lophophorates, a subset of lophotrochozoans bearing ciliated tentacles known as lophophores.[6][15] However, this interpretation has more recently been considered unlikely relative to the deuterostome hypothesis for cambroernid origins.[2]

References

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  1. ^ a b Hagadorn & Allmon 2019
  2. ^ a b c d Caron et al. 2010, p. 2
  3. ^ a b Li et al. 2023
  4. ^ a b Li et al. 2023, p. 2362
  5. ^ Zhu, Zhao & Chen 2002
  6. ^ a b c Dzik, Yuanlong & Maoyan 1997
  7. ^ a b c Lefebvre et al. 2022
  8. ^ Chen, Zhu & Zhou 1995
  9. ^ Caron et al. 2010, p. 7
  10. ^ MacGabhann & Murray 2010
  11. ^ a b Li et al. 2023, pp. 2362–2364
  12. ^ Li et al. 2023, p. 2363
  13. ^ Schroeder, Paterson & Brock 2018
  14. ^ Lieberman et al. 2017, p. 12
  15. ^ Zhang et al. 2006 (Note: Cites the 1999 discovery publication Early Cambrian Chengjiang Fauna from Kunming Region China (Luo Hui-Lin, Hu Shi-Xie, Chen Liang-Zhong, Zhang Shi-Shan, Tau Yong-Shan), which is in Chinese and not available online)

Works cited

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  • Chen, Jun-yuan; Zhu, Mao-yan; Zhou, Gui-qing (1995). "The Early Cambrian medusiform metazoan Eldonia from the Chenjiang Lagerstätte" (PDF). Acta Palaeontologica Polonica. 40 (3): 213–244.213-244&rft.date=1995&rft.aulast=Chen&rft.aufirst=Jun-yuan&rft.au=Zhu, Mao-yan&rft.au=Zhou, Gui-qing&rft_id=https://www.app.pan.pl/archive/published/app40/app40-213.pdf&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">
  • Caron, J.; Conway Morris, S.; Shu, D.; Soares, D. (2010). Soares, Daphne (ed.). "Tentaculate fossils from the Cambrian of Canada (British Columbia) and China (Yunnan) interpreted as primitive deuterostomes". PLOS ONE. 5 (3): e9586. Bibcode:2010PLoSO...5.9586C. doi:10.1371/journal.pone.0009586. PMC 2833208. PMID 20221405.
  • Dzik, Jerzy; Yuanlong, Zhao; Maoyan, Zhu (1997). "Mode of life of the Middle Cambrian eldonioid lophophorate Rotadiscus" (PDF). Palaeontology. 40 (2): 385–396.385-396&rft.date=1997&rft.aulast=Dzik&rft.aufirst=Jerzy&rft.au=Yuanlong, Zhao&rft.au=Maoyan, Zhu&rft_id=https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_40/vol40_part2_pp385-396.pdf&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">
  • Hagadorn, James W.; Allmon, Warren D. (2019-01-01). "Paleobiology of a three-dimensionally preserved paropsonemid from the Devonian of New York". Palaeogeography, Palaeoclimatology, Palaeoecology. Studies in Honor of Prof. David J. Bottjer. 513: 208–214. Bibcode:2019PPP...513..208H. doi:10.1016/j.palaeo.2018.08.007. ISSN 0031-0182. S2CID 133683311.208-214&rft.date=2019-01-01&rft_id=info:doi/10.1016/j.palaeo.2018.08.007&rft_id=https://api.semanticscholar.org/CorpusID:133683311#id-name=S2CID&rft.issn=0031-0182&rft_id=info:bibcode/2019PPP...513..208H&rft.aulast=Hagadorn&rft.aufirst=James W.&rft.au=Allmon, Warren D.&rft_id=https://www.sciencedirect.com/science/article/pii/S0031018218305844&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">
  • Lefebvre, Bertrand; Van Roy, Peter; Zamora, Samuel; Gutiérrez-Marco, Juan Carlos; Nohejlová, Martina (2022-03-31). "The Late Ordovician Tafilalt Biota, Anti-Atlas, Morocco: a high-latitude perspective on the GOBE". Geological Society, London, Special Publications. 485 (1): 5–35. Bibcode:2022GSLSP.485....5L. doi:10.1144/sp485-2022-29. ISSN 0305-8719. S2CID 247351043.5-35&rft.date=2022-03-31&rft_id=info:doi/10.1144/sp485-2022-29&rft_id=https://api.semanticscholar.org/CorpusID:247351043#id-name=S2CID&rft.issn=0305-8719&rft_id=info:bibcode/2022GSLSP.485....5L&rft.aulast=Lefebvre&rft.aufirst=Bertrand&rft.au=Van Roy, Peter&rft.au=Zamora, Samuel&rft.au=Gutiérrez-Marco, Juan Carlos&rft.au=Nohejlová, Martina&rft_id=http://dx.doi.org/10.1144/sp485-2022-29&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">
  • Li, Yujing; Dunn, Frances S.; Murdock, Duncan J.E.; Guo, Jin; Rahman, Imran A.; Cong, Peiyun (May 10, 2023). "Cambrian stem-group ambulacrarians and the nature of the ancestral deuterostome". Current Biology. 33 (12): 2359–2366.e2. Bibcode:2023CBio...33E2359L. doi:10.1016/j.cub.2023.04.048. PMID 37167976. S2CID 258592223.
  • Lieberman, Bruce S.; Kurkewicz, Richard; Shinogle, Heather; Kimmig, Julien; MacGabhann, Brendan Anraoi (June 6, 2017). "Disc-shaped fossils resembling porpitids or eldonids from the early Cambrian (Series 2: Stage 4) of western USA". PeerJ. 5: e3312. doi:10.7717/peerj.3312. PMC 5463991. PMID 28603667.
  • MacGabhann, Breandán Anraoi; Murray, John (2010). "Non-mineralised discoidal fossils from the Ordovician Bardahessiagh Formation, Co. Tyrone, Ireland". Irish Journal of Earth Sciences. 28: 1–12. doi:10.3318/IJES.2010.28.1. hdl:10395/2407. JSTOR 25780702. S2CID 129593969.1-12&rft.date=2010&rft_id=info:hdl/10395/2407&rft_id=https://api.semanticscholar.org/CorpusID:129593969#id-name=S2CID&rft_id=https://www.jstor.org/stable/25780702#id-name=JSTOR&rft_id=info:doi/10.3318/IJES.2010.28.1&rft.aulast=MacGabhann&rft.aufirst=Breandán Anraoi&rft.au=Murray, John&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">
  • Schroeder, Natalie I.; Paterson, John R.; Brock, Glenn A. (2018). "Eldonioids with associated trace fossils from the lower Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia". Journal of Paleontology. 92 (1): 80–86. Bibcode:2018JPal...92...80S. doi:10.1017/jpa.2018.6. ISSN 0022-3360. S2CID 197586878.80-86&rft.date=2018&rft_id=info:doi/10.1017/jpa.2018.6&rft_id=https://api.semanticscholar.org/CorpusID:197586878#id-name=S2CID&rft.issn=0022-3360&rft_id=info:bibcode/2018JPal...92...80S&rft.aulast=Schroeder&rft.aufirst=Natalie I.&rft.au=Paterson, John R.&rft.au=Brock, Glenn A.&rft_id=https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/eldonioids-with-associated-trace-fossils-from-the-lower-cambrian-emu-bay-shale-konservatlagerstatte-of-south-australia/05F449A7147B8DB89E74F26E2A443E88&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">
  • Zhang, Zhifei; Shu, Degan; Han, Jian; Liu, Jianni (2006). "New data on the rare Chengjiang (Lower Cambrian, South China) linguloid brachiopod Xianshanella haikouensis". Journal of Paleontology. 80 (2): 203–211. doi:10.1666/0022-3360(2006)080[0203:NDOTRC]2.0.CO;2.203-211&rft.date=2006&rft_id=info:doi/10.1666/0022-3360(2006)080[0203:NDOTRC]2.0.CO;2&rft.aulast=Zhang&rft.aufirst=Zhifei&rft.au=Shu, Degan&rft.au=Han, Jian&rft.au=Liu, Jianni&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">* Zhu, Mao-Yan; Zhao, Yuan-Long; Chen, Jun-Yuan (2002-03-01). "Revision of the Cambrian discoidal animals Stellostomites eumorphus and Pararotadiscus guizhouensis from South China". Geobios. 35 (2): 165–185. Bibcode:2002Geobi..35..165Z. doi:10.1016/S0016-6995(02)00025-6. ISSN 0016-6995.165-185&rft.date=2002-03-01&rft.issn=0016-6995&rft_id=info:doi/10.1016/S0016-6995(02)50025-6&rft_id=info:bibcode/2002Geobi..35..165Z&rft.aulast=Zhu&rft.aufirst=Mao-Yan&rft.au=Zhao, Yuan-Long&rft.au=Chen, Jun-Yuan&rft_id=https://www.sciencedirect.com/science/article/pii/S0016699502000256&rfr_id=info:sid/en.wikipedia.org:Cambroernid" class="Z3988">


 

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