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Growth rates of pterobranchs and the lifespan of graptolites

Published online by Cambridge University Press:  08 February 2016

Susan Rigby  and
P. Noel Dilly
Susan Rigby
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ United Kingdom
P. Noel Dilly
Affiliation:
Department of Anatomy, St George's Hospital Medical School, Cranmer Terrace, Tooting, London SWI7 ORE United Kingdom
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Abstract

Pterobranchs are the closest living relatives of graptolites. Their skeleton is constructed from the same material, and in a homologous manner. Growth rates of the pterobranch Cephalodiscus gracilis are described for the first time and, along with rhabdopleuran growth rates, they are used to estimate the amount of time invested by a graptolite colony in growing its rhabdosome. This is a measure of minimum age. The significance of age calculations is shown for individuals and large communities of graptoloids. Large individuals can be shown to be much older than the time it would have taken them to settle through seawater and so it is shown that graptoloids moved up, as well as down, through the water column. Life tables constructed for biserial graptoloids from the Utica shale in Quebec, Canada, suggest that these graptoloids died from constant environmental stress. Graptoloid length can thus be a function of environment and should only cautiously be considered to be of taxonomic significance.

Type
Articles
Information
Paleobiology , Volume 19 , Issue 4 , Fall 1993 , pp. 459 - 475
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Andres, D. 1980. Feinstrukturen und Verwandschaftsbeziehungen der graptolithen. Paleontologie Zeitschrift 54:129–170.CrossRefGoogle Scholar
Armstrong, W. G., Dilly, P. N., and Urbanek, A. 1984. Collagen on the pterobranch coenecium and the problem of graptolite affinities. Lethaia 17:145–152.CrossRefGoogle Scholar
Bulman, O. M. B. 1964. Palaeozoic plankton. Quarterly Journal of the Geological Society of London 120:455–476.CrossRefGoogle Scholar
Crowther, P. R. 1981. The fine structure of the graptolite periderm. Special Papers in Palaeontology 26.Google Scholar
Dilly, P. N. 1986. Modern pterobranchs: observations on their behaviour and tube building. Pp. 261–269In Hughes, C. P. and Rickards, R. B., eds. Palaeoecology and biostratigraphy of graptolites. Geological Society Special Publication 20: 261–269.Google Scholar
Dilly, P. N. 1988. Tube building in Cephalodiscus gracilis. Journal of Zoology (London) 216:465–468.CrossRefGoogle Scholar
Dilly, P. N. 1992. Cephalodiscus graptolitoides: a living graptolite? Journal of Zoology (London) 229:69–78.CrossRefGoogle Scholar
Elles, G. L., and Wood, E. M. R. 1901–1918. A monograph of British graptolites. Monograph of the Palaeontological Society.Google Scholar
Finney, S. C. 1979. Mode of life of planktonic graptolites: flotation structure in Ordovician Dicellograptus sp. Paleobiology 5:31–39.CrossRefGoogle Scholar
Gilmour, T. H. J. 1978. Ciliation and function of the food collecting and waste rejecting organs of lophophorates. Canadian Journal of Zoology 56:2142–2155.CrossRefGoogle Scholar
Hutchinson, G. E. 1978. An introduction to population ecology. Yale University Press, New Haven.Google Scholar
Jorgensen, C. B. 1966. The biology of suspension. Pergamon Press, Oxford.Google Scholar
Kirk, N. H. 1969. Some thoughts on the ecology, mode of life and evolution of the Graptolithina. Proceedings of the Geological Society of London 1659:273–292.Google Scholar
Kirk, N. H. 1972. More thoughts on the automobility of graptolites. Journal of the Geological Society of London 128:127–133.CrossRefGoogle Scholar
Kirk, N. H. 1978. Mode of life of graptolites. Acta Palaeontologica Polonica 23:533–555.Google Scholar
Kozlowski, R. 1949. Les graptolithes et quelque nouveaux groupes d'animaux du Tremadoc de la Pologne. Palaeontologica Polonica 3:1–235.Google Scholar
Lack, D. 1943. The age of the blackbird. British Birds 36:166–175.Google Scholar
Lenz, A. C. 1974. A membrane-bearing Cyrtograptus and an interpretation of the hydrodynamics of the cyrtograptids. Special Papers in Palaeontology 13:205–214.Google Scholar
Mitchell, C. E. 1987. Evolution and phylogenetic classification of the Diplograptacea. Palaeontology 30:353–405.Google Scholar
Putman, R. J., and Wratten, S. D. 1984. Principles of ecology. Chapman and Hall, London.Google Scholar
Rickards, R. B. 1975. Paleoecology of the Graptolithina, an extinct class of the Phylum Hemichordata. Biological Reviews of the Cambridge Philosophical Society 50:397–436.CrossRefGoogle Scholar
Rickards, R. B., and Chapman, A. 1991. Bendigonian graptolites (Hemichordata) of Victoria. National Museum of Victoria Memoir Series 52:1–135.CrossRefGoogle Scholar
Rickards, R. B., and Stait, B. A. 1984. Psigraptus, its classification, evolution and zooid. Alcheringa 8:101–111.CrossRefGoogle Scholar
Rigby, S. 1991. Feeding strategies in graptoloids. Palaeontology 34:797–815.Google Scholar
Rigby, S., and Rickards, R. B. 1989. New evidence for the life habit of graptoloids from physical modelling. Paleobiology 15:402–413.CrossRefGoogle Scholar
Ryland, J. S. 1971. Bryozoans. Hutchinson University Library, London.Google Scholar
Stebbing, A. R. D. 1970. Aspects of the reproduction and life cycle of Rhabdopleura compacta (Hemichordata). Marine Biology 5:205–212.CrossRefGoogle Scholar
Sudbury, M. 1991. The dimensions of the graptolite zooid. Geological Magazine 128:381–384.CrossRefGoogle Scholar
Towe, K. M., and Urbanek, A. 1972. Collagen-like structures in Ordovician graptolite periderm. Nature (London) 237:433–445.CrossRefGoogle Scholar