Skip to main content Accessibility help
Hostname: page-component-55597f9d44-mm7gn Total loading time: 0.392 Render date: 2022-08-20T02:52:11.042Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "useRatesEcommerce": false, "useNewApi": true } hasContentIssue true

Reinterpretation of the Cambrian ‘bryozoan’ Pywackia as an octocoral

Published online by Cambridge University Press:  14 July 2015

Paul D. Taylor
Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK,
Björn Berning
Oberösterreichische Landesmuseen, Geowissenschaftliche Sammlungen, Welserstrasse 20 4060 Linz-Leonding, Austria,
Mark A. Wilson
Department of Geology, The College of Wooster, Wooster, OH 44691, USA,


Pywackia baileyi Landing in Landing et al., 2010, from the upper Cambrian Yudachica Member of Oaxaca State, southern Mexico, consists of small, phosphatic, proximally tapering cylindrical rods covered by shallow polygonal calices. The bryozoan-like morphology of this fossil prompted its interpretation as the first bryozoan known from the Cambrian. However, restudy of some of the original material, employing scanning electron microscopy for the first time, questions the assignment of Pywackia to the Bryozoa. Striking similarities between Pywackia and the modern pennatulacean octocoral Lituaria lead to an alternative hypothesis interpreting Pywackia an early fossil octocoral. While Pywackia is probably not a true pennatulacean, a group with a definitive fossil record stretching back only to the Late Cretaceous, it can be envisaged as having had a similar skeletal structure and ecology to Lituaria, the rods representing mineralized axes of tiny colonies that lived with their proximal ends buried in the sediment and distal ends covered by feeding polyps. Landing et al. (2010) considered the phosphatic composition of Pywackia specimens to be the result of diagenetic replacement, but the evidence is equivocal. If Pywackia had a primary phosphatic skeleton, this would support the hypothesized existence of phosphatic biomineralization early in the evolutionary history of Cnidaria, as well as providing further evidence that Pywackia is not a bryozoan.

Research Article
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


Antcliffe, J. B. and Brasier, M. D. 2007. Charnia and sea pens are poles apart. Journal of the Geological Society of London 164:4951.CrossRefGoogle Scholar
Ausich, W. I. and Babcock, L. E. 1998. The phylogenetic position of Echmatocrinus brachiatus, a probable octocoral from the Burgess Shale. Palaeontology 41:193202.Google Scholar
Ausich, W. I. and Babcock, L. E. 2000. Echmatocrinus, a Burgess Shale animal reconsidered. Lethaia 33:9294.Google Scholar
Balinski, A., Sun, Y., and Dzik, J. 2012. 470-million-year-old black corals from China. Naturwissenschaften, 99:645653.CrossRefGoogle ScholarPubMed
Bayer, F. M. and Macintyre, I. G. 2001. The mineral component of the axis and holdfast of some gorgonacean octocorals (Coelenterata: Anthozoa), with special reference to the family Gorgoniidae. Proceedings of the Biological Society of Washington 114:309345.Google Scholar
Bengtson, S. 1981. Atractosella, a Silurian octocoral. Journal of Paleontology, 55:281294.Google Scholar
Bengtson, S., Conway Morris, S., Cooper, B. J., Jell, P. A., and Runnegar, B. N. 1990. Early Cambrian fossils from South Australia. Memoirs of the Australasian Association of Palaeontologists, 9:1364.Google Scholar
Blake, D. B. 1979. The Arthrostylidae and articulated growth habits in Paleozoic bryozoans, p. 337344. InLarwood, G. P. and Abbott, M. B.(eds.), Advances in Bryozoology. Academic Press, London and New York.Google Scholar
Blake, D. B. 1983. Introduction to the suborder Rhabdomesina, p. 530549. InRobison, R. A.(ed.), Treatise on Invertebrate Paleontology, Pt. G., Bryozoa, Revised. Volume 1: Introduction, Order Cystoporata, Order Cryptostomata. Geological Society of America and University of Kansas, Boulder and Lawrence.Google Scholar
Cobbold, E. S. 1931. Additional fossils from the Cambrian rocks of Comley, Shropshire. Quarterly Journal of the Geological Society of London, 87:459512.CrossRefGoogle Scholar
Cobbold, E. S. and Pocock, R. W. 1934. The Cambrian area of Rushton (Shropshire). Philosophical Transactions of the Royal Society of London, Series B, 223:305409.CrossRefGoogle Scholar
Collins, A. G. 2009. Recent insights into cnidarian phylogeny. Smithsonian Contributions to the Marine Sciences, 38:139149.Google Scholar
Conti, S. and Serpagli, E. 1988. Bimineralic (calcareous and phosphatic) skeleton in Late Ordovician Bryozoa from Sardinia: geological implications. Bollettino della Societa Paleontologica Italiana, 23:320.Google Scholar
Cope, J. C. W. 2005. Octocorallian and hydroid fossils from the Lower Ordovician of Wales. Palaeontology, 48:433445.CrossRefGoogle Scholar
Dzik, J. 1994. Bryozoa of the Mójcza Limestone. Palaeontologia Polonica, 53:253282.Google Scholar
Fritz, M. A. 1947. Cambrian Bryozoa. Journal of Paleontology, 21:434435.Google Scholar
Hickson, S. J. 1916. The Pennatulacea of the Siboga Expedition. Siboga-Expeditie, 14:1265.Google Scholar
Hinds, R.W. 1973, Intrazooecial structures in some tubuliporinid cyclostome Bryozoa, p. 299306. InLarwood, G. P.(ed.), Living and Fossil Bryozoa. Academic Press, London.Google Scholar
Imahara, Y. and Ogawa, K. 2006. Rediscovery of Virgularia juncea (Octocorallia, Pennatulacea) from a tidal marsh in Okinawa, with a short note on its peculiar behavior. Proceedings of the 10th International Coral Reef Symposium, p. 913.Google Scholar
Kobluk, D. R. 1984. Archaeotrypa Fritz 1947 (Cambrian, Problematica) reinterpreted. Canadian Journal of Earth Science, 21:13431348.CrossRefGoogle Scholar
Landing, E., English, A., and Keppie, J. D. 2010. Cambrian origin of all skeletalized phyla—discovery of Earth's oldest bryozoans (upper Cambrian, southern Mexico). Geology, 38:547550.CrossRefGoogle Scholar
Landing, E., Westrop, S. R., and Keppie, J. D. 2007. Terminal Cambrian and lowest Ordovician succession of Mexican West Gondwana: biotas and sequence stratigraphy of the Tinu Formation. Geological Magazine, 144:909936.CrossRefGoogle Scholar
Lindström, M. 1978. An octocoral from the Lower Ordovician of Sweden. Geologica et Palaeontologica, 12:4152.Google Scholar
Macintyre, I. G., Bayer, F. M., Logan, M. A. V., and Skinner, H. C. W. 2000. Possible vestiges of early phosphatic biomineralization in gorgonian octocorals (Coelenterata). Geology, 28:455458.2.0.CO;2>CrossRefGoogle Scholar
McFadden, C. S., France, S. C., Sánchez, J. A., and Alderslade, P. 2006. A molecular phylogenetic analysis of the Octocorallia (Cnidaria: Anthozoa) based on mitochondrial protein-coding sequences. Molecular Phylogenetics and Evolution, 41:513527.CrossRefGoogle ScholarPubMed
Park, E., Hwang, D.-S., Lee, J.-S., Song, J.-I., Seo, T.-K., and Won, Y.-J. 2012. Estimation of divergence times in cnidarian evolution based on mitochondrial protein-coding genes and the fossil record. Molecular Phylogenetics and Evolution, 62:329345.CrossRefGoogle ScholarPubMed
Reich, M. and Kutscher, M. 2011. Sea pens (Octocorallia: Pennatulacea) from the Late Cretaceous of northern Germany. Journal of Paleontology, 85:1042–101.CrossRefGoogle Scholar
Taylor, P. D. 1990. Preservation of soft-bodied and other organisms by bioimmuration—a review. Palaeontology, 33:117.Google Scholar
Taylor, P. D. and Ernst, A. 2004. Bryozoans, p. 147156. InWebby, B. D., Paris, F., Droser, M. L., and Percival, I. G.(eds.), The Great Ordovician Biodiversification Event. Columbia University Press, New York.Google Scholar
Taylor, P. D., Vinn, O., and Wilson, M. A. 2010. Evolution of biomineralisation in ‘lophophorates'. Special Papers in Palaeontology, 84:317333.Google Scholar
Waeschenbach, A., Taylor, P. D., and Littlewood, D. T. 2012. A molecular phylogeny of bryozoans. Molecular Phylogenetics and Evolution, 62:718735.CrossRefGoogle ScholarPubMed
Williams, G. C. 1995. Living genera of sea pens (Coelenterata: Octocorallia: Pennatulacea): illustrated key and synopses. Zoological Journal of the Linnean Society, 113:93140.CrossRefGoogle Scholar
Williams, G. C. 1997. Preliminary assessment of the phylogeny of Pennatulacea (Anthozoa: Octocorallia), with a reevaluation of Ediacaran frond-like fossils, and a synopsis of the history of evolutionary thought regarding the sea pens. Proceedings of the 6th International Conference on Coelenterate Biology, 1995, p. 497509.Google Scholar
Williams, G. C. 2011. The global diversity of sea pens (Cnidaria: Octocorallia: Pennatulacea). PLoS ONE, 6, e22747.CrossRefGoogle Scholar
Wyse Jackson, P. N. and Bancroft, A. J. 1995. Generic revision of the cryptostome bryozoan Rhabdomeson Young and Young, 1874, with descriptions of two species from the Carboniferous of the British Isles. Journal of Paleontology, 69:2845.CrossRefGoogle Scholar
Cited by

Save article to Kindle

To save this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the or variations. ‘’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Reinterpretation of the Cambrian ‘bryozoan’ Pywackia as an octocoral
Available formats

Save article to Dropbox

To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.

Reinterpretation of the Cambrian ‘bryozoan’ Pywackia as an octocoral
Available formats

Save article to Google Drive

To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.

Reinterpretation of the Cambrian ‘bryozoan’ Pywackia as an octocoral
Available formats

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *