Skip to main content Accessibility help
×
Home

Polymorphic organization in a planktonic graptoloid (Hemichordata: Pterobranchia) colony of Late Ordovician age

  • JAN A. ZALASIEWICZ (a1), ALEX PAGE (a1), R. BARRIE RICKARDS (a2), MARK WILLIAMS (a1), PHILIP R. WILBY (a1) (a3), MICHAEL P. A. HOWE (a3) and ANDREA M. SNELLING (a3)...

Abstract

Graptolites are common fossils in Early Palaeozoic strata, but little is known of their soft-part anatomy. However, we report a long-overlooked specimen of Dicranograptus aff. ramosus from Late Ordovician strata of southern Scotland that preserves a strongly polymorphic, recalcitrant, organic-walled network hitherto unseen in graptoloid graptolites. This network displays three morphologies: proximally, a strap-like pattern, likely of flattened tubes; these transform distally into isolated, hourglass-shaped structures; then, yet more distally, revert to a (simpler) strap-like pattern. The network most likely represents a stolon-like system, hitherto unknown in graptoloids, that connected individual zooids. Its alternative interpretation, as colonial xenobionts that infested a graptoloid colony and mimicked its architecture, is considered less likely on taphonomic and palaeobiological grounds. Such polymorphism is not known in non-graptolite pterobranchs, which are less diverse and morphologically more conservative: a division of labour between graptoloid zooids for such functions as feeding, breeding and rhabdosome construction may have been the key to their remarkable evolutionary success.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org 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 sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ 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.

      Polymorphic organization in a planktonic graptoloid (Hemichordata: Pterobranchia) colony of Late Ordovician age
      Available formats
      ×

      Send article to Dropbox

      To send 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 use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Polymorphic organization in a planktonic graptoloid (Hemichordata: Pterobranchia) colony of Late Ordovician age
      Available formats
      ×

      Send article to Google Drive

      To send 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 use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Polymorphic organization in a planktonic graptoloid (Hemichordata: Pterobranchia) colony of Late Ordovician age
      Available formats
      ×

Copyright

Corresponding author

*Author for correspondence: jaz1@le.ac.uk

References

Hide All
Bates, D. E. B. 1987. The density of graptoloid skeletal tissue, and its implication for the volume and density of the soft tissue. Lethaia 20, 149–56.
Bates, D. E. B. & Kirk, N. H. 1987. The role of extrathecal tissue in the construction and functioning of some Ordovician and Silurian retiolitid Graptolites. Bulletin of the Geological Society of Denmark 35, 85102.
Bates, D. E. B. & Kirk, N. H. 1991. The ultrastructure, mode of construction and functioning of Ordovician retiolitid graptolites from the Viola Limestone, Oklahoma. Modern Geology 15, 131286.
Bates, D. E. B. & Loydell, D. K. 2000. Parasitism on graptoloid graptolites, Palaeontology 43, 1143–51.
Bjerreskov, M. 1994 Pyrite diagenesis of graptolites from Bornholm. In Graptolite Research Today (eds Chen, X., Erdtmann, B. D. & Ni, Y.-N.), pp. 217–22. Nanjing: Nanjing University Press.
Briggs, D. E. G. 2003. The role of decay and mineralization in the preservation of soft-bodied fossils. Annual Review of Earth and Planetary Science 31, 275301.
Briggs, D. E. G. & Kear, A. J. 1993. Decay and preservation of polychaetes: taphonomic thresholds in soft-bodied organisms. Palaeobiology 19, 107–35.
Briggs, D. E. G., Kear, A. J., Baas, M., de Leeuw, A. J. & Rigby, S. 1995. Decay and composition of the hemichordate Rhabdopleura: implications for the taphonomy of graptolites. Lethaia 28, 1523.
Briggs, D. E. G. & Williams, H. S. 1981. The restoration of flattened fossils. Lethaia 15, 157–64.
Bulman, O. M. B. 1944. The Caradoc (Balclatchie) graptolites from limestones in Laggan Burn, Ayrshire. Part I. Monograph of the Palaeontographical Society, London 97, 142.
Bulman, O. M. B. 1970. Graptolithina with sections on Enteropneusta and Pterobranchia. In Treatise on Invertebrate Palaeontology, Part V (ed. Teichert, C.), pp. 1101. Boulder, Colorado: Geological Society of America; Lawrence, Kansas: University of Kansas Press.
Bulman, O. M. B. & Rickards, R. B. 1966. A revision of Wiman's dendroid and tuboid graptolites. Bulletin of the Geological Institution of the University of Uppsala 43, 173.
Butterfield, N. J. 1990. Organic preservation of non-mineralizing organisms and the taphonomy of the Burgess Shale. Paleobiology 16, 272–86.
Butterfield, N. J. 2003. Exceptional fossil preservation and the Cambrian explosion. Integrative and Comparative Biology 43, 166–77.
Carter, M. C., Gordon, D. P. & Gardner, J. P. A. 2010. Polymorphism and variation in modular animals: morphometric and density analyses of bryozoan avicularia. Marine Ecology Progress Series 399, 117–30.
Chapman, A. J., Durman, P. N. & Rickards, R. B. 1993. Rhabdopleuran hemichordates: new fossil forms and review. Proceedings of the Geologists’ Association 106, 293303.
Crowther, P. R. & Rickards, R. B. 1977. Cortical bandages and the graptolite zooid. Geologica et Palaeontologica 11, 946.
Dilly, P. N. 1972. Some observations on living Rhabdopleura compacta [Hemichordata]. Journal of the Marine Biological Association 52, 443–8.
Dilly, P. N. 1975. The dormant buds of Rhabdopleura compacta (Hemichordata). Cell and Tissue Research 159, 387–97.
Dilly, P. N. 1993. Cephalodiscus graptolitoides sp. nov., probable extant graptolite. Journal of Zoology 229, 6978.
Donoghue, P. & Purnell, M. A. 2009. Distinguishing heat from light in debate over controversial fossils. Bioessays 31, 178–89.
Durman, P. N. & Sennikov, N. V. 1991. A new rhabdopleurid hemichordate from the Middle Cambrian of Siberia. Palaeontology 36, 283–96.
Elles, G. L. & Wood, E. M. R. 1901–1918 A Monograph of British Graptolites. London: Palaeontographical Society, i–clxxi, a–m, 1536.
Hou, X., Aldridge, R. J., Siveter, D. J., Siveter, D. J., Williams, M., Zalasiewicz, J. & Ma, X. 2011. An Early Cambrian hemichordate zooid. Current Biology 21, 15.
Hutt, J. E. 1974. A new group of Llandovery biform monograptids. In Graptolite Studies in Honour of O.M.B. Bulman (eds Rickards, R. B., Jackson, D. E. & Hughes, C. P.), pp. 189203. Special Papers in Palaeontology no. 13. London: Palaeontological Association.
Jackson, D. E. 1971. Development of Glyptograptus hudsoni sp. nov. from Southampton Island, North-West Territories, Canada. Palaeontology 14, 478–86.
Kozłowski, R. 1948. Les graptolithes et quelques nouveaux groupes d'animaux du Tremadoc de la Pologne. Acta Palaeontologia Polonica 3, 1235.
Kozłowski, R. 1962. Crustoidea – nouveau groupe de Graptolithes. Acta Palaeontologica Polonica 7, 352.
Legrand, Ph. 1978. Sur la presence des structures tubulaires a l'interieur des theques de Diplograptus fezzanensis A. Desio. Comptes Rendus de l'Academie des Sciences, Paris, Série D 286, 387–90.
Legrand, Ph. 1979. Premieres observations sur des structures tubulaires a l'interieur des theques de Diplograptus fezzanensis Desio. Essai d'interpretation. In Proceedings of the First International Conference “Advances in graptolite research”, 1977. Acta Palaeontologica Polonica 24, 107–20.
Legrand, Ph. 1986. New data on tubular structures located within diplograptid rhabdosomes and in the surrounding sediment. Hercynica 2, 11123.
Loydell, D. K., Orr, P. J. & Kearns, S. 2004. Preservation of soft tissues in Silurian graptolites from Latvia. Palaeontology 47, 503–13.
Maletz, J., Steiner, M. & Fatka, O. 2005. Middle Cambrian pterobranchs and the question: what is a graptolite? Lethaia 38, 7385.
McKinney, F. K. 2009. Bryozoan-hydroid symbiosis and a new ichnogenus, Caupokeras. Ichnos 16, 193201.
Melchin, M. J. & DeMont, M. E. 1995. Propulsion modes in the Graptolidea: a new model for graptolite locomotion. Paleobiology 21, 110–20.
Page, A., Gabbott, S. E., Wilby, P. R. & Zalasiewicz, J. A. 2008. Ubiquitous Burgess Shale-style “clay templates” in low-grade metamorphic mudrocks. Geology 36, 855–8.
Page, A., Wilby, P. R., Mellish, C. J. T., Williams, M. & Zalasiewicz, J. A. 2009 (for 2008). Dawsonia (Nicholson): linguliform brachiopods, crustacean tail-pieces and a problematicum rather than graptolite ovarian vesicles. Earth & Environmental Science Transactions of the Royal Society of Edinburgh 99, 251–66.
Page, A., Wilby, P. R., Williams, M., Vannier, J., Davies, J. R., Waters, R. & Zalasiewicz, J. A. 2010. Soft-part preservation in a bivalved arthropod from the Late Ordovician of Wales. Geological Magazine 147, 242–52.
Palmer, D. & Rickards, R. B. 1991. Graptolites: Writing in the Rocks. Woodbridge, Surrey: Boydell Press, 182 pp.
Rickards, R. B. 1975. The palaeoecology of the Graptolithina, an extinct class of the phylum Hemichordata. Biological Reviews 50, 397436.
Rickards, R. B., Partridge, P. L. & Banks, M. R. 1991. Psigraptus jacksoni Rickards and Stait – systematics, reconstruction, distribution and preservation. Alcheringa 15, 243–54.
Rigby, S. & Sudbury, M. 1995. Graptolite ontogeny and the size of the graptolite zooid. Geological Magazine 132, 427–33.
Rushton, A. W. A. 2001 (for 2000). The use of graptolites in the stratigraphy of the Southern Uplands: Peach's legacy. Transactions of the Royal Society of Edinburgh: Earth Sciences 91, 341–7.
Sato, A. 2008. Seasonal reproductive activity in the pterobranch hemichordate Rhabdopleura compacta. Journal of the Marine Biological Association 88, 1033–41.
Sherwin, L. & Rickards, B. 2000. Rogercooperia, a new genus of Ordovician glossograptid graptolite from southern Scotland and New South Wales, Australia. Scottish Journal of Geology 36, 159–64.
Stebbing, A. R. D. 1970. Aspects of the reproduction and life cycle of Rhabdopleura compacta (Hemichordata). Marine Biology 5, 205–12.
Sudbury, M. 1958. Triangulate monograptids from the Monograptus gregarius Zone (lower Llandovery) of the Rheidol Gorge (Cardiganshire). Philosophical Transactions of the Royal Society of London B281, 485555.
Sutton, M. D., Briggs, D. E. G., Siveter, D. J. & Siveter, D. J. 2001. A three-dimensionally preserved fossil polychaete worm from the Silurian of Herefordshire, England. Proceedings of the Royal Society, London B268, 2355–63.
Underwood, C. J. 1992. Graptolite preservation and deformation. Palaios 7, 178–86.
Urbanek, A. 1962. The significance of graptoblasts in the life cycle of crustoid graptolites. Acta Palaeontologica Polonica 28, 313–26.
Urbanek, A. & Dilly, P. N. 2000. The stolon system in Rhabdopleura compacta (Hemichordata) and its phylogenetic implications. Acta Palaeontologica Polonica 45, 201–26.
Zalasiewicz, J. A. & Howe, M. P. A. 2003. A case of profound astogenetic metamorphosis: the structure and affinities of Awarograptus nodifer (Törnquist, 1881). Scottish Journal of Geology 39, 45–9.
Zalasiewicz, J. A., Taylor, L., Rushton, A. W. A., Loydell, D. K., Rickards, R. B. & Williams, M. 2009. Graptolites in British stratigraphy. Geological Magazine 146, 785850.

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed