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Avicularia-like structures in a Paleozoic fenestrate bryozoan

Published online by Cambridge University Press:  14 July 2015

F. K. McKinney*
Affiliation:
Department of Geology, Appalachian State University, Boone, North Carolina 28608

Abstract

Structures that mimic the general shape of cheilostome avicularia occur within the Paleozoic fenestrate bryozoan genus Fenestrapora. These structures, here termed aviculomorphs, are isolated within laminar extrazooidal skeleton and are characterized by an elongate triangular outline that surrounds a shallow, concave pit. The acute tip of the triangular structure was elevated above the general level of the surrounding skeleton, as is the case for many avicularia. The aviculomorphs could not have functioned precisely as do avicularia, but like avicularia they are inferred to have had a thickened cuticular mandible that matched the skeletal base and to have been able to articulate the mandible open and closed along a fulcrum on the short side of the triangular skeletal outline.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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References

Banta, W. C. 1975. Origin and early evolution of cheilostome Bryozoa. Documents des Laboratoires de Géologie de la Faculté des Sciences de Lyon Hors Série 3(2), 565582.Google Scholar
Banta, W. C., Perez, F. M., and Santagata, S. 1995. A setigerous collar in Membranipora chesapeakensis n. sp. (Bryozoa): implications for the evolution of cheilostomes from ctenostomes. Invertebrate Biology, 114:8388.Google Scholar
Barnes, D. K. A. 1994. Communities of epibiota on two erect species of Antarctic Bryozoa. Journal of the Marine Biological Association of the United Kingdom, 74:863872.CrossRefGoogle Scholar
Boardman, R. S. 1983. General features of the Class Stenolaemata, p. G49G137. In Robison, R. A. (ed.), Treatise on Invertebrate Paleontology, Part G, Bryozoa, Revised. Geological Society of America and University of Kansas Press, Lawrence.Google Scholar
Boardman, R. S., and Cheetham, A. H. 1973. Degrees of colony dominance in gtenolaemate and gymnolaemate Bryozoa, p. 121220. In Boardman, R. S., Cheetham, A. H. and Oliver, W. A. Jr. (eds.), Animal colonies. Dowden, Hutchinson & Ross, Stroudsburg.Google Scholar
Boardman, R. S., and McKinney, F. K. 1985. Soft part characters in stenolaemate taxonomy, p. 3544. In Nielsen, C. and Larwood, G. P. (eds.), Bryozoa: Ordovician to Recent. Olsen & Olsen, Fredensborg.Google Scholar
Borg, F. 1926. Studies on Recent cyclostomatous Bryozoa. Zoologiska Bidrag från Uppsala, 10:181507.Google Scholar
Cook, P. L. 1963. Observations on live lunulitiform zoaria of Polyzoa. Cahiers de Biologie Marine, 4:407413.Google Scholar
Cook, P. L., and Chimonides, P. J. 1978. Observations on living colonies of Selenaria (Bryozoa, Cheilostomata); 1. Cahiers de Biologie Marine, 19:147158.Google Scholar
Elias, M. K., and Condra, G. E. 1957. Fenestella from the Permian of west Texas. Geological Society of America Memoir, 70, 158 p.Google Scholar
Etheridge, R. 1877. Observations of some Carboniferous Polyzoa. Annals and Magazine of Natural History, 20:116122.CrossRefGoogle Scholar
Hall, J. 1885. On the mode of growth and relations of the Fenestellidae. Report of the State Geologist of New York for the year 1884, 35-45.Google Scholar
Harmer, S. F. 1933. The genera of Reteporidae. Proceedings of the Zoological Society of London, 1933:615627.CrossRefGoogle Scholar
Kaufmann, K. 1968. The biological role of Bugula-type avicularia (Bryozoa). Atti della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano, 108:5460.Google Scholar
Kaufmann, K. 1971. The form and functions of the avicularia of Bugula (Phylum Ectoprocta). Postilla, 151:126.Google Scholar
Lutaud, G. 1977. The bryozoan nervous system, p. 377410. In Woollacott, R. M. and Zimmer, R. L. (eds.), Biology of bryozoans. Academic Press, New York.CrossRefGoogle Scholar
McKinney, F. K. and Jackson, J. B. C. 1989. Bryozoan evolution. Unwin & Hyman, Boston, 238 p.Google Scholar
Morozova, I. P. 1974. Reviziya roda Fenestella. Paleontologicheskiy Zhurnal, 1974(2):5467. (In Russian)Google Scholar
Nielsen, C. and Pedersen, K. J. 1979. Cystid structure and protrusion of the polypide in Crisia (Bryozoa, Cyclostomata). Acta Zoologica, 60:6588.CrossRefGoogle Scholar
Ryland, J. S. 1970. Bryozoans. Hutchinson University Library, London, 175 p.Google Scholar
Silén, L. 1977. Polymorphism, p. 184231. In Woollacott, R. M. and Zimmer, R. L. (eds.), Biology of bryozoans. Academic Press, New York.Google Scholar
Simpson, G. B. 1895. A discussion of the different genera of Fenestellidae. Thirteenth Annual Report of the Sate Geologist of New York for the year 1893, 687-727.Google Scholar
Simpson, G. B. 1897. A handbook of the genera of the North American Palaeozoic Bryozoa. Fourteenth Annual Report of the State Geologist of New York for the year 1894, 405-669.Google Scholar
Taylor, P. D. 1985. Polymorphism in melicerititid cyclostomes, p. 311318. In Nielsen, C. and Larwood, G. P. (eds.), Bryozoa: Ordovician to Recent. Olsen & Olsen, Fredensborg.Google Scholar
Taylor, P. D. 1990. Bioimmured ctenostomes from the Jurassic and the origin of cheilostome Bryozoa. Palaeontology, 33:1934.Google Scholar
Taylor, P. D. 1994a. Systematics of the melicerititid cyclostome bryozoans; introduction and the genera Elea, Semielea and Reptomultelea. Bulletin of The Natural History Museum, London (Geology), 50(1):1103.Google Scholar
Taylor, P. D. 1994b. An early cheilostome bryozoan from the Upper Jurassic of Yemen. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 191:331334.Google Scholar
Ulrich, E. O. 1886. Descriptions of new Silurian and Devonian fossils. Contributions to American Palaeontology, 1:335.Google Scholar
Ulrich, E. O. 1890. Palaeozoic Bryozoa. Geological Survey of Illinois, 8:283688.Google Scholar
Vine, G. R. 1880. On the Carboniferous Polyzoa. Geological Magazine, Decade 2, 7:501512.CrossRefGoogle Scholar
Winston, J. E. 1984. Why bryozoans have avicularia—a review of the evidence. American Museum Novitates, 2789:126.Google Scholar
Winston, J. E. 1986. Victims of avicularia. Marine Ecology, 7:193199.CrossRefGoogle Scholar