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Homeomorphy in Paleozoic bryozoans: a search for explanations

Published online by Cambridge University Press:  08 February 2016

Daniel B. Blake*
Affiliation:
Department of Geology, University of Illinois, Urbana, Illinois 61801

Abstract

Many apparent homeomorphs have been recognized among genera assigned to the Paleozoic stenolaemate bryozoan orders Trepostomata and Cryptostomata. Morphologies are evaluated to determine whether such homeomorphy should be expected, or is likely to have resulted from incomplete taxonomic analysis. Historical and constructional constraints prevalent in the phylum appear to provide ample opportunity for adaptive convergence, a conclusion supported by the occurrence of similar morphologies in distantly related post-Paleozoic bryozoans.

Cryptostomes are distinguished in part by the presence of restricted budding loci. Loci pattern is hypothesized to be the key innovation in the establishment of the clade and the pattern also is considered critical to the evolution of the relatively slender branches and short zooecia typical of cryptostomes.

Loci development does not provide a taxonomic panacea. This is because the hypothesis does not preclude convergent evolution of broadly similar restricted loci in Paleozoic non-cryptostome groups, although presumably the cryptostomes in general would have been best equipped to succeed under conditions favoring restricted loci.

Environmental conditions for the cryptostomes in general and changing life history strategies for rhabdomesoids in particular provide possible controlling factors for the evolution of these bryozoans.

Type
Articles
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Anstey, R. L. and Perry, T. G. 1972. Eden Shale bryozoans: a numerical study (Ordovician, Ohio Valley). Mich. St. Univ. Publ. Mus., Paleontol. Ser. 1. 80 pp.Google Scholar
Armstrong, R. A. and Gilpin, M. E. 1977. Evolution in a time-varying environment. Science. 195:591592.CrossRefGoogle Scholar
Astrova, G. G. 1965. Morphology, evolutionary history and systematics of Ordovician and Silurian bryzoans. Akad. Nauk USSR, Trudy Paleontol. Inst. v. 106. 432 pp.Google Scholar
Bassler, R. S. 1911. The early Paleozoic Bryozoa of the Baltic provinces. U.S. Natl. Mus. Bull. 77. 382 pp.Google Scholar
Bassler, R. S. 1953. Bryozoa. In: Moore, R. C., ed. Treatise on Invertebrate Paleontology, Pt. G. 254 pp. Geol. Soc. Am. and Univ. Kan. Press; Lawrence, Kansas.Google Scholar
Blake, D. B. 1975. The Order Cryptostomata resurrected. pp. 211223. In: David, L., ed. Bryozoa 1974. Docum. Lab. Géol. Fac. Sci. Lyon, H. S. 3.Google Scholar
Boardman, R. S. 1975. Taxonomic characters for phylogenetic classifications of cyclostome Bryozoa. pp. 595606. In: David, L., ed. Bryozoa 1974. Docum. Lab. Géol. Fac. Sci. Lyon, H. S. 3.Google Scholar
Boardman, R. S. and Cheetham, A. H. 1969. Skeletal growth, intracolony variation, and evolution in Bryozoa: a review. J. Paleontol. 43:205223.Google Scholar
Boardman, R. S. and McKinney, F. K. 1976. Skeletal architechture and preserved organs of four sided zooids in convergent genera of Paleozoic Trepostomata (Bryozoa). J. Paleontol. 50:2578.Google Scholar
Borg, F. 1926. Studies on recent cyclostomatous Bryozoa. Zool. Bidrag Från Uppsala. 10:181507.Google Scholar
Brood, K. 1972. Cyclostomatous Bryozoa from the Upper Cretaceous and Danian in Scandinavia. Stockholm Contrib. Geol. v. 26, 464 pp.Google Scholar
Brood, K. 1978. Note on the bryozoan Pustulopora pustulosa (Goldfuss). Zool. Scripta. 7:121123.CrossRefGoogle Scholar
Cheetham, A. H. 1971. Functional morphology and biofacies distribution of cheilostome Bryozoa in the Danian Stage (Paleocene) of Southern Scandinavia. Smith. Contrib. Paleobiol. 6. 88 pp.Google Scholar
Cuffey, R. J. 1967. Bryozoan Tabulipora carbonaria in Wreford Megacyclothem (Lower Permian) of Kansas. Univ. Kan. Paleontol. Contrib. Bryozoa, Art. 1. 96 pp.Google Scholar
Cuffey, R. J. 1973. An improved classification, based upon numerical taxonomic analyses, for higher taxa of entoproct and ectoproct bryozoans. pp. 549564. In: Larwood, G. P., ed. Living and Fossil Bryozoa. Academic Press; London.Google Scholar
Gautier, T. G. 1970. Interpretive morphology and taxonomy of bryozoan genus Tabulipora. Paleontol. Contrib. Univ. Kan. Pap. 48. 22 pp.Google Scholar
Girty, G. C. 1915. Invertebrate Paleontology. pp. 263376. In: Hinds, H. and Greene, F. C., eds. The stratigraphy of the Pennsylvanian Series in Missouri. Missouri Bur. Geol. Mines. 2nd ser., v. 10.Google Scholar
Gorjunova, R. V. and Morozova, I. P. 1979. Late Paleozoic Bryozoa of Mongolia. Acad. Sci. USSR Paleont. Inst.; The Joint Soviet-Mongolian Paleontol. Exped. Trans. v. 9. 140 pp.Google Scholar
Gould, S. J. and Katz, M. 1975. Disruption of ideal geometry in the growth of receptaculitids; a natural experiment in theoretical morphology. Paleobiology. 1:120.CrossRefGoogle Scholar
Grassle, J. F. and Grassle, J. P. 1974. Opportunistic life histories and genetic systems in marine benthic polychaetes. J. Mar. Res. 32:253284.Google Scholar
Huffman, S. F. 1970. The ectoproct (bryozoan) Rhombopora lepidodendroides Meek, Late Pennsylvanian (Virgilian), Nebraska. J. Paleontol. 44:673679.Google Scholar
Jackson, J. B. C. 1977. Competition on marine hard substrata: the adaptive significance of solitary and colonial strategies. Am. Nat. 111:743767.CrossRefGoogle Scholar
Jackson, J. B. C. 1979. Morphological strategies of sessile animals. pp. 499555. In: Larwood, G. and Rosen, B. R., eds. Biology and Systematics of Colonial Organisms. Academic Press; London.Google Scholar
Karklins, O. L. 1969. The cryptostome Bryozoa from the Middle Ordovician Decorah Shale, Minnesota. Minnesota Geol. Surv. Spec. Publ. 6. 122 pp.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 life history parameters of colonial animals. pp. 221222. In: Boardman, R. S., Cheetham, A. H., and Oliver, Wm. A. Jr., eds. Animal Colonies. Dowden, Hutchinson and Ross; Stroudsburg, Pennsylvania.Google Scholar
Lagaiij, R. and Gautier, Y. 1965. Bryozoan assemblages from marine sedments of the Rhone Delta, France. Micropaleontology. 11:3958.CrossRefGoogle Scholar
Männil, R. 1961. On the morphology of the hemispheric zoaria of the Trepostomata (Bryozoa). Trudy Ist. Geol. Akad. Nauk Estonskoj SSR. 6:113140.Google Scholar
McKinney, F. K. 1972. Nonfenestrate Ectoprocta (Bryozoa) of the Bangor Limestone (Chester) of Alabama. Geol. Sur. Alabama. 98. 144 pp.Google Scholar
McKinney, F. K. 1977. Autozooecial budding patterns in dendroid Paleozoic bryozoans. J. Paleontol. 51:303329.Google Scholar
McKinney, F. K. and Cuffey, R. J. 1977. Living reteporid bryozoans as paleoecological analogues of Paleozoic fenestrate bryozoans. Geol. Soc. Am., Abstr. with Programs. 9:630631.Google Scholar
McLeod, J. D. 1978. The oldest bryozoans: new evidence from the early Ordovician. Science. 200:771773.CrossRefGoogle ScholarPubMed
Morozova, I. P. and Viskova, L. A. 1977. Historical development of marine Bryozoa (Ectoprocta). Paleontol. J. 11(4):393408. (Paleontol. Zhur. in transl.)Google Scholar
Nekhoroshev, V. P. 1956. Lower Carboniferous Bryozoa of Altai and Siberia. Vses. Nauchno-Issled. Geol., Inst. Min. Geol. (VSEGEI), n. ser., v. 13. 420 pp.Google Scholar
Newton, G. B. 1971. Rhabdomesoid bryozoans of the Wreford Magacyclothem (Wolfcampian, Permian) of Nebraska, Kansas, and Oklahoma. Univ. Kan. Paleontol. Contrib. Art. 56, Bryoza 2. 74 pp.Google Scholar
Nichols, J. D., Conley, W., Batt, B., and Tipton, A. R. 1976. Temporally dynamic reproductive strategies and the concept of r- and K-selection. Am. Nat. 110:9951005.CrossRefGoogle Scholar
Pianka, E. R. 1970. On r- and K-selection. Am. Nat. 104:592597.CrossRefGoogle Scholar
Pohowsky, R. A. 1973. A Jurassic cheilostome from England. pp. 447462. In: Larwood, G. P., ed. Living and Fossil Bryozoa. Academic Press; London.Google Scholar
Ross, J. P. R. 1964. Morphology and phylogeny of early Ectoprocta (Bryozoa). Geol. Soc. Am. Bull. 75:927948.CrossRefGoogle Scholar
Ross, J. P. R. 1970. Distribution, paleoecology and correlation of Champlainian Ectoprocta (Bryozoa), New York State, Part III. J. Paleontol. 44:346382.Google Scholar
Ross, J. P. R. 1972. Paleoecology of Middle Ordovician ectoproct assemblages. In: Proc. 24th Int. Geol. Congr. Montreal, sec. 7. pp. 96102.Google Scholar
Ross, J. P. R. 1979. Ectoproct adaptations and ecological strategies. pp. 283294. In: Larwood, G. P. and Abbott, M. B., eds. Advances in Bryozoology. Academic Press; London.Google Scholar
Ryland, J. S. 1970. Bryozoans. 176 pp. Hutchinson Univ. Library; London.Google Scholar
Schopf, T. J. M. 1969. Paleoecology of ectoprocts (Bryozoans). J. Paleontol. 43:234244.Google Scholar
Schopf, T. J. M. 1977. Patterns and themes of evolution among the Bryozoa. pp. 159208. In: Hallam, A., ed. Patterns of Evolution. Elsevier Sci. Pub. Co.; Amsterdam.Google Scholar
Seilacher, A. 1970. Arbeitskonzept zur konstruktions-morphologie. Lethaia. 3:393396.CrossRefGoogle Scholar
Shishova, N. A. 1968. New order of Paleozoic bryozoans. Paleontol. J. 2(1):117121. (Paleontol. Zhur. in transl.)Google Scholar
Silén, L. and Harmelin, J. G. 1974. Observations on living Diastoporidae (Bryozoa Cyclostomata), with special regard to polymorphism. Acta Zool. 55:8196.CrossRefGoogle Scholar
Stach, L. W. 1936. Correlation of zoarial form with habitat. J. Geol. 44:6066.CrossRefGoogle Scholar
Stearns, S. C. 1976. Life history tactics: a review of the ideas. Q. Rev. Biol. 51:347.CrossRefGoogle ScholarPubMed
Stearns, S. C. 1977. The evolution of life history traits: a critique of the theory and a review of the data. Annu. Rev. Ecol. Syst. 8:145171.CrossRefGoogle Scholar
Tavener-Smith, R. 1975. The phylogenetic affinities of the fenestelloid bryozoans. Palaeontology. 18:117.Google Scholar
Tavener-Smith, R. and Williams, A. 1972. The secretion and structure of the skeleton of living and fossil Bryozoa. Phil. Trans. R. Soc. (London) B. 264:97159.Google Scholar
Thomsen, E. 1977. Phenetic variability and functional morphology of erect cheilostome bryozoans from the Danian (Palaeocene) of Denmark. Paleobiology. 3:360376.CrossRefGoogle Scholar
Utgaard, J. 1973. Mode of growth, autozooids, and polymorphism in the bryozoan Order Cystoporata. pp. 317360. In: Boardman, R. S., Cheetham, A. H., and Oliver, W. A. Jr., eds. Animal Colonies. Dowden, Hutchinson and Ross, Inc.; Stroudsburg, Pennsylvania.Google Scholar
Walker, K. R. and Ferrigno, K. F. 1973. Major Middle Ordovician reef tract in East Tennessee. Am. J. Sci. 273A:294325.Google Scholar
Winston, J. E. 1979. Current-related morphology and behavior in some Pacific coast bryozoans. pp. 247268. In: Larwood, G. P. and Abbott, M. B., eds. Advances in Bryozoology. Academic Press; London.Google Scholar