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Figure 12.20 (a) Cluster analysis of bryozoan growth forms across a shelf-slope transition, showing an inner shelf A (clastic dominated), inner shelf B (carbonate dominated), outer shelf and slope. The cluster analysis, using a distance coefficient (x-axis) and average group linkage, indicates the presence of four distinctive assemblages. (b) Distribution of growth forms across the onshore-offshore gradient within the assemblages identified by cluster analysis. (Based on Hageman et al. 1997.)

Figure 12.20 (a) Cluster analysis of bryozoan growth forms across a shelf-slope transition, showing an inner shelf A (clastic dominated), inner shelf B (carbonate dominated), outer shelf and slope. The cluster analysis, using a distance coefficient (x-axis) and average group linkage, indicates the presence of four distinctive assemblages. (b) Distribution of growth forms across the onshore-offshore gradient within the assemblages identified by cluster analysis. (Based on Hageman et al. 1997.)

Review questions

1 Current brachiopod research suggests that the phylum Brachiopoda can be split into three subphyla: Linguliformea, Crani-iformea and Rhynchonelliformea. What sort of criteria can we use to discover how each subphylum was related to each other and the stem-group brachiopod?

2 Brachiopod shells store a huge amount of data, not only about the secretion of the shell, but also about its surrounding environment. How have brachiopod shells, particularly their stable isotopes, contributed to our understanding of climate change?

3 Although the thick-shelled and ornate productid brachiopods of the Late Paleozoic were resistant to attack, why did bra-chiopods apparently not feature much in the Mesozoic marine revolution or Meso-zoic arms race?

4 The "dawn of the Danian" witnessed a marked change in bryozoan faunas with the dominance of the cheilostomes over the cyclostomes. Both are ecologically similar so why were the cheilostomes relatively more successful after the KT extinction event?

5 Brachiopods and bryozoans were both conspicuous members of the filter-feeding Paleozoic evolutionary fauna. Why then are brachiopods a relatively minor part of the Recent marine fauna but bryozoans continue to flourish?

Boardman, R.S. & Cheetham, A.H. 1987. Phylum Bryozoa. In Boardman, R.S., Cheetham, A.H. & Rowell, A.J. (eds) Fossil Invertebrates. Blackwell Scientific Publications, Oxford, UK, pp. 497-549. (A comprehensive, more advanced text with emphasis on taxonomy; extravagantly illustrated.)

Carlson, S.J. & Sandy, M.R. (eds) 2001. Brachiopods Ancient and Modern. A tribute to G. Arthur Cooper. Paleontological Society Papers No. 7. University of Yale, New Haven, CT. (Diverse aspects of contemporary brachiopod research.)

Clarkson, E.N.K. 1998. Invertebrate Palaeontology and Evolution, 4th edn. Chapman and Hall, London. (An excellent, more advanced text; clearly written and well illustrated.)

Cocks, L.R.M. 1985. Brachiopoda. In Murray, J.W. (ed.) Atlas of Invertebrate Macrofossils. Longman,

London, pp. 53-78. (A useful, mainly photographic review of the group.)

Harper, D.A.T., Long, S.L. & Nielsen, C. (eds) 2008. Brachiopoda: Fossil and Recent. Fossils and Strata 54, 1-331. (Most recent proceedings from an international brachiopod congress.)

Kaesler, R.L. (ed.) 2000-2007. Treatise on Invertebrate Paleontology. Part H, Brachiopoda (revised), vols 1-6. Geological Society of America and University of Kansas, Boulder, CO/Lawrence, KS. (Up-to-date compendium of most aspects of the phylum.)

McKinney, F.K. & Jackson, J.B.C. 1989. Bryozoan Evolution. Unwin Hyman, London. (Evolutionary studies of the phylum.)

Rowell, A.J. & Grant, R.E. 1987. Phylum Brachiopoda. In Boardman, R.S., Cheetham, A.H. & Rowell, A.J. (eds) Fossil Invertebrates. Blackwell Scientific Publications, Oxford, UK, pp. 445-96. (A comprehensive, more advanced text with emphasis on taxonomy; extravagantly illustrated.)

Rudwick, M.J.S. 1970. Living and Fossil Brachiopods. Hutchinson, London. (Landmark text.)

Ryland, J.S. 1970. Bryozoans. Hutchinson, London. (Fundamental text.)

Taylor, P.D. 1985. Bryozoa. In Murray, J.W. (ed.) Atlas of Invertebrate Macrofossils. Longman, London, pp. 47-52. (A useful, mainly photographic review of the group.)

Taylor, P.D. 1999. Bryozoa. In Savazzi, E. (ed.) Functional Morphology of the Invertebrate Skeleton. Wiley, Chichester, UK, pp. 623-46. (Comprehensive review of the functional morphology of the group.)

References

Clarkson, E.N.K. 1998. Invertebrate Palaeontology and Evolution, 4th edn. Chapman and Hall, London.

Cohen, B.L., Holmer, L.E. & Luter, C. 2003. The brachiopod fold: a neglected body plan hypothesis. Palaeontology 46, 59-65.

Freeman, G. & Lundelius, J.W. 2005. The transition from planktotrophy to lecithotrophy in larvae of lower Palaeozoic Rynchoneliiform brachiopods. Lethata 38, 219-54.

Geldern, van, R., Joachimski, M.M., Day, J., Jansen, U., Alvarez, F., Yolkin, E.A. & Ma, X.-P. 2006. Carbon, oxygen and strontium isotope records of Devonian brachiopod shell calcite. Palaeogeography, Palaeocli-matology, Palaeoecology 240, 47-67.

Hageman, S.J. 2003. Complexity generated by iteration of hierarchical modules in Bryozoa. Integrated Comparative Biology 43, 87-98.

Hageman, S.J., Bone, Y., McGowran, B. & James, N.P. 1997. Bryozoan colonial growth-forms as palaeoen-vironmental indicators: evaluation of methodology. Palaios 12, 405-19.

Harper, D.A.T., Alsen, P., Owen, E.F. & Sandy, M.R. 2005. Early Cretaceous brachiopods from North-

Further reading

East Greenland: biofacies and biogeography. Bulletin of the Geological Society of Denmark 52, 21325.

Harper, E.M. 2006. Dissecting arms races. Palaeogeog-raphy, Palaeoclimatology, Palaeoecology 232, 322-43.

Lidgard, S., McKinney, F.K. & Taylor, P.D. 1993. Competition, clade replacement, and a history of cyclo-stome and cheilostome bryozoan diversity. Paleobiology 19, 352-71.

McKinney, F.K. & Taylor, P.D. 2001. Bryozoan genetric extinctions and originations during the last 100 million years. Palaeontologia Electronica 4, 26 pp.

O'Dea, A. 2003. Seasonality and zooid size variation in Panamanian encrusting bryozoans. Journal of the Marine Biological Association 83, 1107-8.

Perez-Huerta, A., Cusack, M., Zhu, W.-Z., England, J. & Hughes, J. 2007. Material properties of the bra-chiopod ultrastructure by nanoindentation. Interface 4, 33-9.

Robinson, J.H. & Lee, D.E. 2008. Brachiopod pedicle traces: recognition of three separate types of trace and redefinition of Podichnus centrifugalis Bromley & Surlyk, 1973. Fossils and Strata 54, 219-25.

Schumann, D. 1991. Hydrodynamic influences in brachiopod shell morphology of Terebratalia transversa (Sowerby) from the San Juan Islands. In MacKinnon, D.I., Lee, D.E. & Campbell, J.D. (eds) Brachiopods through Time. A.A. Balkema, Rotterdam.

Taylor, P.D. 1985. Bryozoa. In Murray, J.W. (ed.) Atlas of Invertebrate Macrofossils. Longman, London, pp. 47-52.

Taylor, P.D. 2005. Bryozoans and palaeoenvironmental interpretation. Journal of the Palaeontological Society of India 50, 1-11.

Taylor, P.D. & Vinn, O. 2006. Convergent morphology in the small spiral worm tubes ("Spirobis") and its palaeoenvironmental implications. Journal of the Geological Society, London 163, 225-8.

Williams, A., Carlson, S.J., Brunton, C.H.C., Holmer, L.E. & Popov, L. 1996. A supra-ordinal classification of the Brachiopoda. Philosophical Transactions of the Royal Society B 351, 1171-93.

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, 20311.

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