Hostname: page-component-8448b6f56d-t5pn6 Total loading time: 0 Render date: 2024-04-24T11:01:48.465Z Has data issue: false hasContentIssue false
  • English
  • Français

Functional morphology of arborescent animals: strength and design of cheilostome bryozoan skeletons

Published online by Cambridge University Press:  08 February 2016

Alan H. Cheetham  and
Erik Thomsen
Alan H. Cheetham
Affiliation:
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560
Erik Thomsen
Affiliation:
Department of Palaeoecology, Aarhus University, DK-8000 Aarhus C, Denmark
Get access Rights & Permissions [Opens in a new window]

Abstract

In cheilostome bryozoans with rigidly arborescent growth habits, resistance to breakage under forces generated by flowing water or collision with moving objects depends on the strength and design of supporting skeletal parts. To investigate the abilities of modern and Tertiary cheilostomes to resist breakage, we measured bending strength in fresh, preserved, and fossil material; measured drag on actual and model colonies; and calculated stress within colonies and breaking values under concentrated and uniform loads. Among nine modern, five Oligocene, and four Paleocene species, inferred live bending strength (24–85 MNm−2) and stiffness (42–65 GNm−2) appear to be species-specific properties overlapping those of similar mineral-organic composite skeletons of Mollusca. Unlike those of Mollusca, cheilostome skeletons appear isotropic in bending, with strength not clearly related to microstructure or composition. Bending strength and morphologic disposition of skeletal material combine to produce a wide range of abilities to resist breaking. At early growth stages, almost all species appear highly resistant; at later ones, some break at velocities <0.2 m sec−1 or concentrated loads <2 g, whereas others remain unbroken at velocities >2 m sec−1 or concentrated loads >100 g. A negative correlation between strength and resistance indicates that design is the more important factor in the abilities of these bryozoans to withstand forces of these kinds. An apparent trend toward more resistant designs from Paleocene to modern species is related chiefly to increasing rates at which branches thicken toward the colony base. The consequent change in design may even have permitted modern species to use weaker skeletal material while increasing their overall resistance.

Type
Articles
Information
Paleobiology , Volume 7 , Issue 3 , Summer 1981 , pp. 355 - 383
Copyright
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.)

References

Literature Cited

Alexander, R. M. 1968. Animal Mechanics. 346 pp. Univ. Washington Press; Seattle.Google Scholar
Alexander, R. M. 1977. The progress of animal mechanics. pp. 3–11. In: Nachtigall, W., ed. Physiology of Movement—Biomechanics. Gustav Fisher Verlag; Stuttgart.Google Scholar
Askren, L. T. Jr. 1968. Bryozoan paleoecology from the Tertiary of Alabama. Southeastern Geol. 9:157–163.Google Scholar
Banta, W. C. 1968. The body wall of cheilostome Bryozoa. I. The ectocyst of Watersipora nigra (Canu and Bassler). J. Morphol. 125. 497–508.CrossRefGoogle ScholarPubMed
Banta, W. C. 1971. The body wall of cheilostome Bryozoa. IV. The frontal wall of Schizoporella unicornis Johnston). J. Morphol. 135:165–184.Google ScholarPubMed
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
Bottjer, D. J. 1980. Branching morphology of the reef coral Acropora cervicornis in different hydraulic regimes. J. Paleontol. 54:1102–1107.Google Scholar
Caldwell, D. R. and Chriss, T. M. 1979. The viscous sublayer at the sea floor. Science. 205:1131–1132.CrossRefGoogle ScholarPubMed
Canu, F. and Bassler, R. S. 1920. North American Early Tertiary Bryozoa. U.S. Natl. Mus. Bull. 106:879 pp.Google Scholar
Chamberlain, J. A. Jr. 1978. Mechanical properties of coral skeleton: compressive strength and its adaptive significance. Paleobiology. 4:419–435.CrossRefGoogle Scholar
Chamberlain, J. A. Jr. and Graus, R. R. 1975. Water flow and hydromechanical adaptations of branched reef corals. Bull. Mar. Sci. 25:112–125.Google Scholar
Cheetham, A. H. 1954. A new Early Cretaceous cheilostome bryozoan from Texas. J. Paleontol. 28:177–184.Google Scholar
Cheetham, A. H. 1963. Late Eocene zoogeography of the Eastern Gulf Coast region. Geol. Soc. Am., Mem. 91:113 pp.Google Scholar
Cheetham, A. H. 1966. Cheilostomatous Polyzoa from the Upper Bracklesham Beds (Eocene) of Sussex. Bull. Brit. Mus. (Nat. Hist.): Geol. 13:1–115.Google Scholar
Cheetham, A. H. 1971. Functional morphology and biofacies distribution of cheilostome Bryozoa in the Danian Stage (Paleocene) of southern Scandinavia. Smithson. Contrib. Paleobiol. 6:87 pp.Google Scholar
Cheetham, A. H. 1975. Taxonomic significance of autozooid size and shape in some early multiserial cheilostomes from the Gulf Coast of the U.S.A. pp. 547–564. In: Pouyet, S., ed. Bryozoa 1974. Docum. Lab. Géol. Fac. Sci. Lyon. h. sér. 3. 2.Google Scholar
Cheetham, A. H. and Cook, P. L. 1982. General features of the class Gymnolaemata. In: Robison, R. A., ed. Treatise on Invertebrate Paleontology, Supplements and Revisions. Part G, Bryozoa, vol. 1.Google Scholar
Cheetham, A. H. and Håkansson, E. 1972. Preliminary report on Bryozoa (Site 117). pp. 432–441. In: Laughton, A. S. et al. Initial Reports of the Deep Sea Drilling Project. 12.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
Cheetham, A. H., Hayek, L. C., and Thomsen, E. 1981. Growth models in fossil arborescent cheilostome bryozoans. Paleobiology. 7:68–86.CrossRefGoogle Scholar
Cheetham, A. H., Rucker, J. B., and Carver, R. E. 1969. Wall structure and mineralogy of the cheilostome bryozoan Metrarabdotos. J. Paleontol. 43:129–135.Google Scholar
Cockbain, A. E. 1969. Notes on cheilostomatous Bryozoa from the Eucla Group, Western Australia. Geol. Surv. Western Australia. 1969/8:1–8.Google Scholar
Cook, P. L. 1973. Preliminary notes on the ontogeny of the frontal body wall in the Adeonidae and Adeonellidae (Bryozoa, Cheilostomata). Bull. Brit. Mus. (Nat. Hist.). 25:245–263.Google Scholar
Currey, J. D. 1975. A comparison of the strength of echinoderm spines and mollusc shells. J. Mar. Biol. Ass. U.K. 55:419–424.CrossRefGoogle Scholar
Currey, J. D. 1976. Further studies on the mechanical properties of mollusc shell material. J. Zool., London. 180:445–453.CrossRefGoogle Scholar
Currey, J. D. 1979. The effect of drying on the strength of mollusc shells. J. Zool., London. 188:301–308.CrossRefGoogle Scholar
Currey, J. D. and Kohn, A. J. 1976. Fracture in the crossed-lamellar structure of Conus shells. J. Materials Sci. 11:1615–1623.CrossRefGoogle Scholar
Currey, J. D. and Taylor, J. D. 1974. The mechanical behaviour of some molluscan hard tissues. J. Zool., London. 173:395–406.CrossRefGoogle Scholar
Dailey, J. W. and Harleman, D. R. F. 1966. Fluid Dynamics. 454 pp. Addison-Wesley Publ. Co., Inc.; Reading, Mass.Google Scholar
Ditlev, H. 1980. A Field-guide to the Reef-building Corals of the Pacific. Dr. W. Backhuys Publisher; Rotterdam and Scandinavian Science Press Ltd.; Klampenborg.CrossRefGoogle Scholar
Dzik, J. 1975. The origin and early phylogeny of the cheilostomatous Bryozoa. Acta Palaeontol. Polonica. 20:395–423.Google Scholar
Faupel, J. H. 1964. Engineering Design. 980 pp. John Wiley and Sons, Inc.; New York.Google Scholar
Foster, A. B. 1977. Patterns of small-scale variation of skeletal morphology within the scleractinian corals, Montastrea annularis and Siderastrea sidera. Proc. Third Internatl. Coral Reef Symp. pp. 410–415.Google Scholar
Foster, A. B. 1979. Phenotypic plasticity in the reef corals Montastrea annularis (Ellis & Solander) and Siderastrea sidera (Ellis & Solander). J. Exp. Mar. Biol. Ecol. 39:25–54.CrossRefGoogle 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 Geol. no. 4. Am. Assoc. Petrol. Geol.; Tulsa, Okla.Google Scholar
Grigg, R. W. 1972. Orientation and growth form of sea fans. Limnol. Oceanogr. 17:185–192.CrossRefGoogle Scholar
Hadley, M. L. 1964. Wave-induced bottom currents in the Celtic Sea. Mar. Geol. 2:164–167.CrossRefGoogle Scholar
Hoerner, S. F. 1958. Fluid-Dynamic Drag; Practical Information on Aerodynamic Drag and Hydrodynamic Resistance. Technical Library, Bellcomm, Inc.Google Scholar
Hubbard, J. A. E. B. 1974. Scleractinian coral behaviour in calibrated current experiment: an index to their distribution patterns. Proc. Second Internatl. Coral Reef Symp. pp. 107–126.Google Scholar
Jackson, J. B. C. 1979. Overgrowth competition between encrusting cheilostome ectoprocts in a Jamaican cryptic reef environment. J. Animal Ecol. 48:805–823.CrossRefGoogle Scholar
Jokiel, P. L. 1978. Effects of water motion on reef corals. J. Exp. Mar. Biol. Ecol. 35:87–97.CrossRefGoogle Scholar
Jokiel, P. L. and Cowdin, H. P. 1976. Hydromechanical adaptation in the solitary free-living coral Fungia scutaria. Nature. 262:212–213.CrossRefGoogle Scholar
Kerper, M. J. and Scuderi, T. G. 1963. Mechanical properties of glass at elevated temperatures. Am. Ceramic Soc. Bull. 42:735–740.Google Scholar
Labracherie, M. 1972. La profondeur et le substrat, deux facteurs écologiques 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. géol. France. 3:142.Google Scholar
Labracherie, M. and Sigal, J. 1975. Les bryozoaires cheilostomes des formations Eocène inférieur du Site 246 (Croisière 25, Deep Sea Drilling Project). pp. 449–466. In: Pouyet, S., ed. Bryozoa 1974. Docum. Lab. Géol. Fac. Sci. Lyon. h. sér. 3. 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
Lang, W. D. 1914a. On Herpetopora, a new genus containing three new species of Cretaceous cheilostome Polyzoa. Geol. Mag. dec. 6. 1:5–8.CrossRefGoogle Scholar
Lang, W. D. 1914b. Some new genera and species of Cretaceous cheilostome Polyzoa. Geol. Mag. dec. 6. 1:436–444.CrossRefGoogle Scholar
Lang, W. D. 1915. On some new uniserial Cretaceous cheilostome Polyzoa. Geol. Mag. dec. 6. 2:496–504.CrossRefGoogle Scholar
Larwood, G. P. 1975. Preliminary report on early (pre-Cenomanian) cheilostome Bryozoa. pp. 539–545. In: Pouyet, S., ed. Bryozoa 1974. Docum. Lab. Géol. Fac. Sci. Lyon. h. sér. 3. 2.Google Scholar
Larwood, G. P. and Taylor, P. D. 1979. Early structural and ecological diversification in the Bryozoa. pp. 209–234. In: House, M. R., ed. The Origin of Major Invertebrate Groups. Syst. Assoc. Spec. Vol. no. 12. Academic Press; London.Google Scholar
Lowenstam, H. A. 1954. Factors affecting the aragonite-calcite ratios in carbonate-secreting marine organisms. J. Geol. 62:284–322.CrossRefGoogle Scholar
Marcus, E. and Marcus, E. 1962. On some lunulitiform Bryozoa. Bol. Fac. Fil., Ciěn., Letr., Univ. São Paulo. Zoologia. 24:281–324.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
Nye, O. B., Dean, D. A., and Hinds, R. W. 1972. Improved thin section techniques for fossil and recent organisms. J. Paleontol. 46:271–275.Google Scholar
Pennycuick, C. J. 1967. The strength of the pigeon's wing bones in relation to their function. J. Exp. Biol. 46:219–233.CrossRefGoogle ScholarPubMed
Pohowsky, R. A. 1973. A Jurassic cheilostome from England. pp. 447–461. In: Larwood, G. P., ed. Living and Fossil Bryozoa. Academic Press; London.Google Scholar
Poluzzi, A. and Sartori, R. 1973. Carbonate mineralogy of some Bryozoa from Talbot Shoal (Strait of Sicily, Mediterranean). Giorn. Geol. ser. 2a. 39:11–15.Google Scholar
Poluzzi, A. and Sartori, R. 1975. Report on the carbonate mineralogy of Bryozoa. pp. 193–210. In: Pouyet, S., ed. Bryozoa 1974. Docum. Lab. Géol. Fac. Sci. Lyon. h. sér. 3. 1.Google Scholar
Powell, N. A. 1968. Bryozoa (Polyzoa) of Arctic Canada. J. Fish. Res. Board. Canada. 25:2269–2320.CrossRefGoogle Scholar
Riedl, R. 1971. Water movement: animals. pp. 1123–1156. In: Kinne, O., ed. Marine Ecology. Vol. 1, pt. 2. Wiley-Interscience; London.Google Scholar
Rucker, J. B. and Carver, R. E. 1969. A survey of the carbonate mineralogy of cheilostome Bryozoa. J. Paleontol. 43:791–799.Google Scholar
Sandberg, P. A. 1971. Scanning electron microscopy of cheilostome bryozoan skeletons: techniques and preliminary observations. Micropaleontology. 17:129–151.CrossRefGoogle Scholar
Sandberg, P. A. 1975. Bryozoan diagenesis: bearing on the nature of the original skeleton of rugose corals. J. Paleontol. 49:587–606.Google Scholar
Sandberg, P. A. 1977. Ultrastructure, mineralogy, and development of bryozoan skeletons. pp. 143–181. In: Woollacott, R. M. and Zimmer, R. L., eds. Biology of Bryozoans. Academic Press; New York.CrossRefGoogle Scholar
Schopf, T. J. M. 1969. Paleoecology of ectoprocts (bryozoans). J. Paleontol. 43:234–244.Google Scholar
Schopf, T. J. M., Collier, K. O., and Bach, B. O. 1981. Relation of the morphology of stick-like bryozoans at Friday Harbor, Washington, to bottom currents, suspended matter and depth. Paleobiology. 6:466–476.CrossRefGoogle Scholar
Schopf, T. J. M. and Manheim, F. T. 1967. Chemical composition of Ectoprocta (Bryozoa). J. Paleontol. 41:1197–1225.Google Scholar
Schumacher, H. 1973. Morphologische und ökologische Anpassungen von Acabaria-Arten (Octocorallia) im Roten Meer an verschiedene Formen der Wasserbewegung. Helgoländer Wiss. Meersunters. 25:461–472.CrossRefGoogle Scholar
Seilacher, A. 1970. Arbeitskonzept zur Konstruktions-Morphologie. Lethaia. 3:393–396.CrossRefGoogle Scholar
Singer, F. L. 1962. Strength of Materials. 590 pp. 2nd ed.Harper & Brothers, Publ.; New York.Google Scholar
Slatt, R. M. 1977. Late Quaternary terrigenous and carbonate sedimentation on Grand Bank of Newfoundland. Bull. Geol. Soc. Am. 88:1357–1367.2.0.CO;2>CrossRefGoogle Scholar
Sokal, R. R. and Rohlf, F. J. 1969. Biometry: The Principles and Practice of Statistics in Biological Research. 776 pp. W. H. Freeman; San Francisco.Google Scholar
Tavener-Smith, R. and Williams, A. 1970. Structure of the compensation sac in two ascophoran bryozoans. Proc. R. Soc. London. 175B:235–254.Google Scholar
Tavener-Smith, R. and Williams, A. 1972. The secretion and structure of the skeleton of living and fossil Bryozoa. Philos. Trans. R. Soc. London. Sect. B, Biol. Sci. 264:97–159.Google Scholar
Taylor, J. D. and Layman, M. 1972. The mechanical properties of bivalve (Mollusca) shell structure. Palaeontology. 15:73–87.Google Scholar
Thomas, H. D. and Larwood, G. P. 1956. Some “uniserial” membraniporine polyzoan genera and a new American Albian species. Geol. Mag. 93:369–376.CrossRefGoogle Scholar
Thomas, H. D. and Larwood, G. P. 1960. The Cretaceous species of Pyripora d'Orbigny and Rhammatopora Lang. Palaeontology. 3:370–386.Google Scholar
Thomsen, E. 1977. Phenetic variability and functional morphology of erect cheilostome bryozoans from the Danian (Paleocene) of Denmark. Paleobiology. 3:360–376.CrossRefGoogle Scholar
Van Valen, L. 1978. Arborescent animals and other colonoids. Nature. 276:318.CrossRefGoogle Scholar
Velimirov, B. 1976. Variations in growth forms of Eunicella cavolinii Koch (Octocorallia) related to intensity of water movement. J. Exp. Mar. Biol. Ecol. 21:109–117.CrossRefGoogle Scholar
Voigt, E. 1959. La signification stratigraphique des bryozoaires dans le Crétacé supérieur. Congrès Soc. Savantes. 84:701–707.Google Scholar
Vosburgh, F. 1977. The response to drag of the reef coral Acropora reticulata. Proc. Third Internatl. Coral Reef Symp. pp. 477–482.Google Scholar
Wainwright, S. A., Biggs, W. D., Currey, J. D., and Gosline, J. M. 1976. Mechanical Design in Organisms. 423 pp. Halsted Press (Wiley); New York.Google Scholar
Wainwright, S. A. and Dillon, J. R. 1969. Orientation of sea fans. Biol. Bull. 136:130–139.CrossRefGoogle Scholar
Wainwright, S. A. and Koehl, M. A. R. 1976. The nature of flow and the reaction of benthic Cnidaria to it. pp. 5–21. In: Mackie, G. O., ed. Coelenterate Ecology and Behavior. Plenum Press; New York.CrossRefGoogle Scholar
Warner, G. F. 1977. On the shapes of passive suspension feeders. pp. 567–576. In: Keegan, B. F., Ceidigh, P. O., and Boaden, P. J. S., eds. Biology of Benthic Organisms. Pergamon Press; Oxford.CrossRefGoogle Scholar
Wass, R. E. and Yoo, J. J. 1975. Bryozoa from Site 282 west of Tasmania. pp. 809–831. In: Kennett, J. P. et al. Initial Reports of the Deep Sea Drilling Project. 29.CrossRefGoogle Scholar
Woodley, J. D. 1980. Hurricane Allen destroys Jamaican coral reefs. Nature. 287:387.CrossRefGoogle Scholar