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Growth models in fossil arborescent cheilostome bryozoans

Published online by Cambridge University Press:  08 February 2016

Alan H. Cheetham ,
Lee-Ann C. Hayek  and
Erik Thomsen
Alan H. Cheetham
Affiliation:
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560
Lee-Ann C. Hayek
Affiliation:
Scientific Applications Division, Office of Computer Services, Smithsonian Institution, Washington, D.C. 20560
Erik Thomsen
Affiliation:
Department of Palaeoecology, Aarhus University, DK-8000, Aarhus C, Denmark
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Abstract

Cheilostome bryozoans that grew as rigidly erect arborescent colonies dominate many bryozoan-rich assemblages of Tertiary age, in which they are found most commonly as small dissociated fragments. The regularity with which branching and branch thickening occur in intact colonies of living species provides a basis for quantitative reconstruction of these growth processes in fossils. We propose models to describe branch thickening, develop methods to extend both thickening and branching models to fossils, investigate the thickening and branching properties of four Paleocene and five Oligocene species and compare the properties of these fossils to those of nine living species.

The properties investigated are largely mutually independent and species specific irrespective of geologic age and have similar numerical ranges among different assemblages of coeval species. Species are evenly distributed across the range of possible morphologies between observed extremes, without obvious gaps. Statistically significant trends through time are identified in gradients of branch thickening, which have implications for the resistance of colonies to mechanical stress, and in angles of bifurcation, that are important in the way growing colonies occupy space.

Type
Articles
Information
Paleobiology , Volume 7 , Issue 1 , Winter 1981 , pp. 68 - 86
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Alexander, R. M. 1971. Size and Shape. Studies in Biology. No. 29. 59 pp. Edward Arnold Ltd.; London.Google Scholar
Askren, L. T. Jr. 1968. Bryozoan paleoecology from the Tertiary of Alabama. Southeastern Geol. 9: 157–163.Google Scholar
Banta, W. C. 1972. The body wall of cheilostome Bryozoa. V. Frontal budding in Schizoporella unicornis floridana. Mar. Biol. 14: 63–71.Google Scholar
Boardman, R. S. and Cheetham, A. H. 1973. Degrees of colony dominance in stenolaemate and gymnolaemate Bryozoa. pp. 121–220. In: Boardman, R. S., Cheetham, A. H., and Oliver, W. A. Jr., eds. Animal Colonies. Dowden, Hutchinson & Ross, Inc.; Stroudsburg, Pa.Google Scholar
Boardman, R. S., Cheetham, A. H., and Cook, P. L. 1970. Intracolony variation and the genus concept in Bryozoa. Proc. North Am. Paleontol. Convention, 1969. 1 (c):294–320.Google Scholar
Canu, F. and Bassler, R. S. 1920. North American Early Tertiary Bryozoa. U.S. Natl. Mus. Bull. 106: 1–879.Google Scholar
Canu, F. and Bassler, R. S. 1933. The bryozoan fauna of the Vincentown limesand. U.S. Natl. Mus. Bull. 165: 1–108.Google Scholar
Cheetham, A. H. 1963. Late Eocene zoogeography of the Eastern Gulf Coast region. Geol. Soc. Am. Mem. 91: 1–113.Google Scholar
Cheetham, A. H. 1966. Cheilostomatous Polyzoa from the Upper Bracklesham Beds (Eocene) of Sussex. Bull. Brit. Mus. (Nat. Hist.) Geol. 13(1):1–115.Google Scholar
Cheetham, A. H. 1968. Morphology and systematics of the bryozoan genus Metrarabdotos. Smithsonian Misc. Coll. 153(1):1–121.Google Scholar
Cheetham, A. H. 1971. Functional morphology and biofacies distribution of cheilostome Bryozoa in the Danian stage (Paleocene) of southern Scandinavia. Smithsonian Contrib. Paleobiol. 6: 1–87.Google Scholar
Cheetham, A. H. and Håkansson, E. 1972. Preliminary report on Bryozoa (Site 117). In: Laughton, A. S. et al. Initial Reports of the Deep Sea Drilling Project. 12: 432–441.Google Scholar
Cheetham, A. H., Hayek, L. C., and Thomsen, E. 1980. Branching structure in arborescent animals: models of relative growth. J. Theor. Biol. 85: 335–369.CrossRefGoogle ScholarPubMed
Cockbain, A. E. 1969. Notes on cheilostomatous Bryozoa from the Eucla Group, Western Australia. Geol. Surv. W. Austral. No. 1969/8. 8 pp.Google Scholar
Graus, R. R., Chamberlain, J. A. Jr., and Boker, A. M. 1977. Structural modification of corals in relation to waves and currents. pp. 135–153. In: Frost, S. H., Weiss, M. P., and Saunders, J. B., eds. Reefs and Related Carbonates—Ecology and Sedimentology. Studies in Geology No. 4. Am. Assoc. Petrol. Geol.; Tulsa, Oklahoma.CrossRefGoogle Scholar
Hazel, J. E., Mumma, M. D., and Huff, W. J. 1980. Ostracode biostratigraphy of the lower Oligocene (Vicksburgian) of Mississippi and Alabama. Trans. Gulf Coast Assoc. Geol. Socs. 30: 361–401.Google Scholar
Jackson, J. B. C. 1979. Morphological strategies of sessile animals. pp. 499–555. In: Larwood, G. and Rosen, B. R., eds. Biology and Systematics of Colonial Organisms. Syst. Assoc. Spec. vol. 11. Academic Press; London.Google Scholar
Kaufmann, K. W. 1970. A model for predicting the influence of colony morphology on reproductive potential in the Phylum Ectoprocta. Biol. Bull. 139: 426.Google Scholar
Kaufmann, K. W. 1973. The effect of colony morphology on the life-history parameters of colonial animals. pp. 221–222. In: Boardman, R. S., Cheetham, A. H., and Oliver, W. A. Jr., eds. Animal Colonies. Dowden, Hutchinson, and Ross, Inc.; Stroudsburg, Pa.Google Scholar
Labracherie, M. 1972. Le profondeur et le substrat, deux facteurs écologique de la répartition des peuplements de Bryozoaires durant l'Eocène nord-aquitain. Bull. Inst. Géol. Bassin d'Aquitaine. 12: 25–41.Google Scholar
Labracherie, M. 1973. Functional morphology and habitat of Bryozoa in the Eocene of the northern Aquitaine Basin, France. pp. 129–138. In: Larwood, G. P., ed. Living and Fossil Bryozoa. Academic Press; London.Google Scholar
Labracherie, M. and Prud'homme, J. 1966. Essai d'interprétation de paléomilieux grǎce à la méthode de distribution des formes zoariales chez les Bryozoaires. (Résumé). C. R. Soc. Geol. France. 3: 142.Google Scholar
Labracherie, M. and Sigal, J. 1975. Les Bryozoaires Cheilostomes des formations Eocène inferieur du Site 246 (Croisiere 25, Deep Sea Drilling Project). pp. 449–466. In: Pouyet, S., ed. Bryozoa 1974. Docum. Lab. Geol. Fac. Sci. Lyon. h. sér. 3, fasc. 2.Google Scholar
Lagaaij, R. and Gautier, Y. V. 1965. Bryozoan assemblages from marine sediments of the Rhǒne delta, France. Micropaleontology. 11: 39–58.CrossRefGoogle Scholar
McMahon, T. A. and Kronauer, R. E. 1976. Tree structures: deducing the principle of mechanical design. J. Theor. Biol. 59: 443–466.CrossRefGoogle ScholarPubMed
Olsson, R. K. 1970. Paleocene planktonic foraminiferal biostratigraphy and paleozoogeography of New Jersey. J. Paleontol. 44: 589–597.Google Scholar
Schopf, T. J. M. 1977. Patterns and themes of evolution among the Bryozoa. pp. 159–207. In: Hallam, A., ed. Patterns of Evolution. Elsevier Publishing Company; Amsterdam.Google Scholar
Stach, L. W. 1937. The application of Bryozoa in Cainozoic stratigraphy. Rep. Aust. New Zealand Assoc. Adv. Sci. 23rd Meeting. pp. 80–83.Google Scholar
Stevens, P. S. 1974. Patterns in Nature. 240 pp. Little, Brown and Company; Boston, Toronto.Google Scholar
Thomsen, E. 1976. Depositional environment and development of Danian bryozoan biomicrite mounds (Karlby Klint, Denmark). Sedimentology. 23: 485–509.CrossRefGoogle Scholar
Thomsen, E. 1977a. Relations between encrusting bryozoans and substrate: an example from the Danian of Denmark. Bull. Geol. Soc. Denmark. 26: 133–145.CrossRefGoogle Scholar
Thomsen, E. 1977b. Phenetic variability and functional morphology of erect cheilostome bryozoans from the Danian (Paleocene) of Denmark. Paleobiology. 3: 360–376.CrossRefGoogle Scholar
Wass, R. E. and Yoo, J. J. 1975. Bryozoa from Site 282 west of Tasmania. In: Kennett, J. P. et al. Initial Reports of the Deep Sea Drilling Project. 29: 809–831.Google Scholar