Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-10-31T23:21:03.176Z Has data issue: false hasContentIssue false

Morphological differentiation of Avicularia and the proliferation of species in mid-Cretaceous Wilbertopora Cheetham, 1954 (Bryozoa: Cheilostomata)

Published online by Cambridge University Press:  20 May 2016

Alan H. Cheetham
Affiliation:
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20650,
Joann Sanner
Affiliation:
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20650,
Paul D. Taylor
Affiliation:
Department of Palaeontology, The Natural History Museum, London SW7 5BD, England,
Andrew N. Ostrovsky
Affiliation:
Department of Invertebrate Zoology, Faculty of Biology and Soil Science, St. Petersburg State University, Universitetskaja nab. 7/9, 199034 St. Petersburg, Russia

Abstract

Discovery of avicularium-like polymorphs in Wilbertopora mutabilis Cheetham, 1954 has provided not only a new opportunity for revising the genus Wilbertopora Cheetham, 1954, but also a more detailed basis for documenting the series of morphological changes by which avicularia differentiated from ordinary feeding zooids in what appears to be the first occurrence of these characteristic cheilostome bryozoan structures in the fossil record.

Eighteen of a total 60 quantitative characters measured on avicularia and ordinary and ovicell-bearing autozooids were sufficient to distinguish eight species of Wilbertopora by discriminant function analysis of zooid data from 93 colonies from the mid-Cretaceous (Albian-Cenomanian) Washita Group in northeastern Texas and southeastern Oklahoma. Eighteen of a total of 20 of the quantitative characters that could be statistically coded for cladistic analysis proved to be informative with respect to parsimony, providing two maximally parsimonious trees for the eight species. Two-thirds of the diagnostic characters involve avicularia. An additional 55 colonies too poorly preserved for morphometric analysis could then be assigned to species qualitatively, with 170 more colonies lacking species-diagnostic characters.

The cladistic trees strongly suggest that most or all of the species diverged before the end of the Albian, but stratigraphic resolution is insufficient to test this hypothesis. Nevertheless, the series of morphological changes differentiating avicularia from ordinary autozooids in these species, based on the cladistic relationships, is highly significant statistically, and may be a pattern later repeated in other cheilostomes.

Wilbertopora and W. mutabilis are emended, and seven new species are described: W. listokinae, W. tappanae, W. spatulifera, W. attenuata, W. improcera, W. acuminata, and W. hoadleyae.

Type
Research Article
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

Banta, W. C. 1973. Evolution of avicularia in cheilostome Bryozoa, p. 295303. In Boardman, R. S., Cheetham, A. H., and Oliver, W. A. Jr. (eds.), Animal Colonies: Development and Function through Time. Dowden, Hutchinson, and Ross, Stroudsburg, Pennsylvania.Google Scholar
Banta, W. C. 1975. Origin and early evolution of cheilostome Bryozoa, p. 565582. In Pouyet, Simone (ed.), Bryozoa 1974. Documents des Laboratoires de Géologie de la Faculté des Sciences de Lyon, hors-série 3, fasc. 2.Google Scholar
Boardman, R. S., and Cheetham, A. H. 1969. Skeletal growth, intra-colony variation, and evolution in Bryozoa: A review. Journal of Paleontology, 43:205233.Google Scholar
Boardman, R. S., and Cheetham, A. H. 1973. Degrees of colony dominance in stenolaemate and gymnolaemate Bryozoa, p. 121220. In Boardman, R. S., Cheetham, A. H., and Oliver, W. A. Jr. (eds.), Animal Colonies: Development and Function through Time. Dowden, Hutchinson, and Ross, Stroudsburg, Pennsylvania.Google Scholar
Brydone, R. M. 1910. Notes on new or imperfectly known Chalk Polyzoa. Geological Magazine, Decade 5, 7:258260.Google Scholar
Budd, A. F., and Coates, A. G. 1992. Nonprogressive evolution in a clade of Cretaceous Montastraea-like corals. Paleobiology, 18:425446.Google Scholar
Canu, F. 1900. Révision des Bryozoaires du Crétacé figurés par d'Orbigny. Deuzièm partie—Cheilostomata. Bulletin de la Société Géologique de France, série 3, 28:334463.Google Scholar
Cheetham, A. H. 1954. A new Early Cretaceous bryozoan from Texas. Journal of Paleontology, 28:177184.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., p. 547564. In Pouyet, Simone (ed.), Bryozoa 1974. Documents des Laboratoires de Géologie de la Faculté des Sciences de Lyon, hors-série 3, fasc. 2.Google Scholar
Cheetham, A. H. 1986. Tempo of evolution in a Neogene bryozoan: Rates of morphologic change within and across species boundaries. Paleobiology, 12:190202.Google Scholar
Cheetham, A. H., and Cook, P. L. 1983. General features of the class Gymnolaemata, p. 138207. In Robison, R. A. (ed.), Treatise on Invertebrate Paleontology. Pt. G. Bryozoa. Geological Society of America and University of Kansas Press, Lawrence.Google Scholar
Cheetham, A. H., and Lorenz, D. M. 1976. A vector approach to size and shape comparisons among zooids in cheilostome bryozoans. Smithsonian Contributions to Paleobiology, Number 29, 55 p.Google Scholar
Cheetham, A. H., Jackson, J. B. C., and Sanner, J. 2001. Evolutionary significance of sexual and asexual modes of propagation in Neogene species of the bryozoan Metrarabdotos in tropical America. Journal of Paleontology, 75:564577.Google Scholar
Cook, P. L. 1968. Polyzoa from West Africa, the Malacostega, Pt. I. Bulletin of the British Museum (Natural History), Zoology, 16(3):115160.Google Scholar
Cook, P. L. 1979. Some problems in interpretation of heteromorphy and colony integration in Bryozoa, p. 193210. In Larwood, G. P. and Rosen, B. R. (eds.), Biology and Systematics of Colonial Organisms. Academic Press, London.Google Scholar
Cuffey, R. J., Feldman, R. M., and Pohlable, K. E. 1981. New Bryozoa from the Fox Hills Sandstone (Upper Cretaceous, Maestrichtian) of North Dakota. Journal of Paleontology, 55:401409.Google Scholar
Dzik, J. 1975. The origin and early phylogeny of the cheilostomatous Bryozoa. Acta Palaeontologica Polonica, 20:395423.Google Scholar
Farris, J. S. 1988. Hennig 86 Reference, Version 1.5. Farris, Stony Brook, New York, 17 p.Google Scholar
Gordon, D. P. 1984. The marine fauna of New Zealand, Bryozoa: Gymnolaemata from the Kermadec Ridge. New Zealand Oceanographic Institute, Memoir 91, 198 p.Google Scholar
Gray, J. E. 1848. List of the Specimens of British Animals in the Collection of the British Museum. Pt. 1. Centroniae or Radiated Animals. British Museum, London, 173 p.Google Scholar
Guha, A. K. 1989. Upper Cretaceous cheilostomes (Bryozoa) from the Bagh sediments of Madhya Pradesh, p. 118131. In Kalia, P. (ed.), Micropaleontology of the Shelf Sequences of India. Papyrus Publishing House, New Delhi.Google Scholar
Herrera-Cubilla, A., Dick, M. H., Sanner, J., and Jackson, J. B. C.In press. Neogene Cupuladriidae of tropical America, I, Taxonomy of Recent Cupuladria from opposite sides of the Isthmus of Panama. Journal of Paleontology, 80(2).Google Scholar
Jackson, J. B. C., and Cheetham, A. H. 1990. Evolutionary significance of morphospecies: A test with cheilostome Bryozoa. Science, 248:579583.Google Scholar
Jackson, J. B. C., and Cheetham, A. H. 1994. Phylogeny reconstruction and the tempo of speciation in cheilostome Bryozoa. Paleobiology, 20:407423.Google Scholar
Lang, W. D. 1915. On some new uniserial Cretaceous cheilostome Polyzoa. Geological Magazine, decade 6, 2:496504.Google Scholar
Marcus, E. 1938. Bryozoarios marinhos Brasileiros, II. Boletins da Faculdade de Philosofia, Sciencias e Letras, IV, Zoologia, 2:1196.Google Scholar
Norman, A. M. 1903. Notes on the natural history of East Finmark, Polyzoa. Annals and Magazine of Natural History, Series 7, 11:567598.Google Scholar
Norusis, M. J. 1994a. SPSS Base System, 6.1. SPSS, Inc., Chicago, 941 p.Google Scholar
Norusis, M. J. 1994b. SPSS Professional Statistics, 6.1. SPSS, Inc., Chicago, 385 p.Google Scholar
Ostrovsky, A. N., and Taylor, P. D.In press. Early stages of the ovicell development in the calloporid Wilbertopora (Bryozoa: Cheilostomata) from the Upper Cretaceous of the USA. Proceedings of the 13th IBA Conference, Conception, Chile.Google Scholar
Page, R. D. M. 1996. Treeview, an application to display phylogenetic trees on personal computers. Computer Applications in the Biosciences, 12:357358.Google Scholar
Pohowsky, R. A. 1973. A Jurassic cheilostome from England, p. 447461. In Larwood, G. P. (ed.), Living and Fossil Bryozoa. Academic Press, London.Google Scholar
Ryland, J. S., and Gordon, D. P. 1977. Some New Zealand and British species of Hippothoa (Bryozoa: Cheilostomata). Journal of the Royal Society of New Zealand, 7:1749.Google Scholar
Silén, L. 1945. The main features of the development of the ovum, embryo and ooecium in the ooeciferous Bryozoa Gymnolaemata. Arkiv för Zoologi, 35A(17):134.Google Scholar
Swofford, D. L. 2000. PAUP, phylogenetic analysis using parsimony (and other methods), version 4. Sinauer Associates, Sunderland, Massachusetts.Google Scholar
Taylor, P. D. 1986. Charixa Lang and Spinicharixa gen. nov., cheilostome bryozoans from the Lower Cretaceous. Bulletin of the British Museum (Natural History), Geology Series, 40:197222.Google Scholar
Taylor, P. D. 1988. Major radiation of cheilostome bryozoans: Triggered by the evolution of a new larval type? Historical Biology, 1:4564.Google Scholar
Taylor, P. D. 1994. An early cheilostome bryozoan from the Upper Jurassic of Yemen. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 191:331344.Google Scholar
Taylor, P. D. 2002. Bryozoans, p. 5375. In Smith, A. B. and Batten, D. J. (eds.), Fossils of the Chalk (second edition). Palaeontological Association, London.Google Scholar
Taylor, P. D., and Badve, R. M. 1994. The mid-Cretaceous bryozoan fauna from the Bagh Beds of central India: Composition and evolutionary significance, p. 181186. In Hayward, P. J., Ryland, J. S., and Taylor, P. D. (eds.), Biology and Palaeobiology of Bryozoans. Olsen and Olsen, Fredensborg.Google 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.Google Scholar
Winston, J. E. 1991. Avicularian behavior—A progress report, p. 531540. In Bigey, Françoise P. (ed.), Bryozoaires Actuels et Fossiles: Bryozoa Living and Fossil. Bulletin de la Société des Sciences Naturelles de l'Ouest de la France, Mémoire Hors Série, 1.Google Scholar