Species discrimination and evolutionary mode of Buchia (Bivalvia: Buchiidae) from Upper Jurassic–Lower Cretaceous strata of Grassy Island, British Columbia, Canada

51 3 May 583 595 10.1111/j.1475-4983.2008.00765.x

GREY, M., HAGGART, J. W., SMITH, P. L. 2008. Species discrimination and evolutionary mode of Buchia (Bivalvia: Buchiidae) from Upper Jurassic–Lower Cretaceous strata of Grassy Island, British Columbia, Canada. Palaeontology, 51, 3, 583–595.

Melissa Grey, James W. Haggart and Paul L. Smith Buchiid bivalves are geographically widespread in Upper Jurassic and Lower Cretaceous strata of the Northern Hemisphere. They are often abundant and their short stratigraphic ranges make them ideal biostratigraphic index fossils; these characteristics also render them useful for study of evolutionary patterns. We used multivariate methods to determine if we could discriminate between species of Buchia and examine how morphological characters change through time within the genus. Using ten morphological characters to describe shell shape and size, we tested for taxonomic differences and morphologic change in populations of buchiids collected from a single stratigraphic section on Grassy Island, located along the west coast of Vancouver Island, British Columbia. Morphometric analysis utilized traditional morphological metrics and techniques, including linear and angular measurements as well as Fourier (outline shape) analyses. Phenetic discrimination revealed considerable overlap among the recognized species in the morphospace, as well as a fairly low discriminatory power between species when compared as a group using a step-wise canonical variate analysis. Step-wise discriminant analyses between species pairs gave rise to much higher classification rates, suggesting that different characters are important for distinguishing between different species pairs. Our results also indicate that single individuals and small sample sizes of Buchia specimens are insufficient for biostratigraphic discrimination (unless other rarely preserved features such as the hinge and bysuss ear are available) and that a number of previously described species variants may not be taxonomically valid. A biolog using the multivariate axis that best discriminates between species (CV1) and a random walk-based test using a Hurst estimate analysis indicate a gradualistic evolutionary mode for the Buchia species of Grassy Island. Shell shape and size of buchiids do not appear to be closely tied to lithofacies changes over the c. 10 myr time interval, suggesting that ecophenotypic variation (as it relates to substrate changes) probably had minimal influence on morphology.
  • BANCROFT, M. F. 1937. Gold-bearing deposits on the west coast of Vancouver Island between Esperanza Inlet and Alberni Canal. Geological Survey of Canada, Memoir, 204, 34 pp.
  • CHEETHAM, A. H., SANNER, J., TAYLOR, P. D. and OSTROVSKY, A. N. 2006. Morphological differentiation of Avicularia and the proliferation of species in mid-Cretaceous Wilbertopora Cheetham, 1954 (Bryozoa: Cheilostomata). Journal of Paleontology, 80, 49–71.
  • CRAMPTON, J. S. 1994. Shape analysis of pterioid bivalves, its utility in high resolution biostratigraphic studies. 16. In RICCARDI, A. C. (ed.). Advances in Jurassic research: abstracts, 4th International Congress on Jurassic Stratigraphy and Geology .
  • CRAMPTON, J. S. 1995. Elliptic Fourier shape analysis of fossil bivalves: some practical considerations. Lethaia, 28, 179–186.
  • CRAMPTON, J. S. 1996. Biometric analysis, systematics and evolution of Albian Actinoceramus (Cretaceous Bivalvia, Inoceramidae). Monograph of the Institute of Geological and Nuclear Sciences (New Zealand), 15, 1–80.
  • CRAMPTON, J. S. and GALE, A. S. 2005. A plastic boomerang: speciation and intraspecific evolution in the Cretaceous bivalve Actinoceramus. Paleobiology, 31, 559–577.
  • CRAMPTON, J. S. and HAINES, A. J. 1996. User’s manual for programs HANGLE, HMATCH, and HCURVE for the Fourier shape analysis of two-dimensional outlines, 96/37, 28 pp.
  • CRAMPTON, J. S. and MAXWELL, P. A. 2000. Size: all it’s shaped up to be? Evolution of shape through the lifespan of the Cenozoic bivalve Spissatella (Crassatellidae). 399–423. In HARPER, E. M., TAYLOR, J. D. and CRAME, J. A. (eds). The evolutionary biology of the Bivalvia. Geological Society, London, Special Publication, 177, 494 pp.
  • CRICKMAY, C. H. 1925. The geology and paleontology of the Harrison Lake district, British Columbia, together with a review of the Jurassic faunas and stratigraphy of western North America. Stanford University, Stanford, CA, 88 pp.
  • CRICKMAY, C. H. 1930. Fossils from Harrison Lake area, British Columbia. Geological Survey of Canada, Bulletin, 63, 33–60.
  • FORTEY, R. A. 1988. Seeing is believing: gradualism and punctuated equilibria in the fossil record. Scientific Progress, 72, 1–19.
  • GABB, W. M. 1864. Description of the Cretaceous fossils. California Geological Survey, Palaeontology, 1, 57–243.
  • GEARY, D. H. 1987. Evolutionary tempo and mode in a sequence of the Upper Cretaceous bivalve Pleurocardia. Paleobiology, 16, 140–151.
  • GREY, M., HAGGART, J. W. and JELETZKY, J. A. 2007. Uppermost Jurassic (Portlandian) to lowermost Cretaceous (Valanginian) section at Grassy Island, west coast of Vancouver Island, British Columbia. Geological Survey of Canada, Open-File, 5666, 52 pp.
  • GREY, H., HAGGART, J. M. and SMITH, P. L. 2008. A new species of Buchia (Bivalvia: Buchiidae) from British Columbia, Canada, with an analysis of buchiid bipolarity. Journal of Palaeontology, 82, 391–397.
  • HAINES, A. J. and CRAMPTON, J. S. 2000. Improvements to the method of Fourier shape analysis as applied in morphometric studies. Palaeontology, 43, 765–783.
  • HAMMER, O. 2000. A theory for the formation of commarginal ribs in mollusc shells by regulative oscillation. Journal of Molluscan Studies, 66, 383–391.
  • HAMMER, O., HARPER, D. A. T. and RYAN, P. D. 2001. PAST: Paleontological statistics software package for education and data analysis. Palaeontologia Electronica, 4, 9 pp.
  • IMLAY, R. W. 1959. Succession and speciation of the pelecypod Aucella. United States Geological Survey, Professional Paper, 314-G, 155–169, pls 16–19.
  • JELETZKY, J. A. 1950. Stratigraphy of the west coast of Vancouver Island between Kyuquot Sound and Esperanza Inlet, British Columbia. Geological Survey of Canada, Paper, 50-37, 51 pp.
  • JELETZKY, J. A. 1965. Late Upper Jurassic and early Lower Cretaceous fossil zones of the Canadian western Cordillera, British Columbia. Geological Survey of Canada, Bulletin, 103, 70 pp., 22 pls.
  • JELETZKY, J. A. 1966. Upper Volgian (latest Jurassic) ammonites and buchias of Arctic Canada. Geological Survey of Canada, Bulletin, 128, 51 pp., 8 pls.
  • KAUFFMAN, E. G. 1973. Cretaceous Bivalvia. 353–384. In HALLAM, A. (ed.). Atlas of palaeobiogeography. Elsevier Scientific, New York, NY, 531 pp.
  • KELLEY, P. H. 1983. Evolutionary patterns of eight Chesapeake Group molluscs: evidence for the model of Punctuated Equilibria. Journal of Paleontology, 57, 581–598.
  • KELLY, S. R. A. 1990. Biostratigraphy of the bivalve Buchia in the Late Jurassic and Early Cretaceous sediments of Europe. 129–151. In MENNER, V. V. (ed.). The Jurassic-Cretaceous boundary. Trudy Instituta Geologii i Geofiziki, Sibirskoe Otdelenie, 699 , 192 pp, 8 pls. [In Russian].
  • KOWALEWSKI, M., DYRESON, E., MARCOT, J. D., VARGAS, J. A., FLESSA, K. W. and HALLMAN, D. P. 1997. Phenetic discrimination of biometric simpletons: paleobiological implications of morphospecies in the lingulide brachiopod Glottidia. Paleobiology, 23, 444–469.
  • LAHUSEN, I. 1888. Uber die russischen Aucellen. Mémoires du Comité Géologique (St Petersburg), 8, 45 pp.
  • MARKO, P. B. and JACKSON, J. B. C. 2001. Patterns of morphological diversity among and within arcid bivalve species pairs separated by the Isthmus of Panama. Journal of Paleontology, 75, 590–606.
  • MULLER, J. E., CAMERON, B. E. B. and NORTHCOTE, K. E. 1981. Geology and mineral deposits of Nootka Sound map-area, Vancouver Island, British Columbia. Geological Survey of Canada, Paper, 80-16, 53 pp.
  • NEWELL, N. D. and BOYD, D. W. 1970. Oyster-like Permian Bivalvia. Bulletin of the American Museum of Natural History, 143, 221–281.
  • ORBIGNY, A. d’ 1845. Mollusques. 419–512. In : Géologie de la Russie d’Europe et des Montagnes de l’Oural. Systéme Jurassique. Volume 2. J. Murray and Bertrand, London and Paris, 512 pp.
  • PAVLOW, A. P. 1907. Enchaînement des aucelles et aucellines du crétacé Russe. Nouveaux Mémoirs de la Société Impériale Naturalistes de Moscou, 5, 455–570.
  • REYMENT, R. A. 1980. Morphometric methods in biostratigraphy. Academic Press, London, 175 pp.
  • ROOPNARINE, P. D. 2001. The description and classification of evolutionary mode: a computational approach. Paleobiology, 27, 446–465.
  • ROOPNARINE, P. D., BYARS, G. and FITZGERALD, P. 1999. Anagenetic evolution, stratophenetic patterns, and random walk models. Paleobiology, 25, 41–57.
  • ROUILLIER, C. 1845. Explication de la coupe géologique des environs de Moscou. Bulletin de la Société Impériale des Naturalistes de Moscou, 19, 359–467.
  • SCHATZ, W. 2001. Taxonomic significance of biometric characters and the consequences for classification and biostratigraphy, exemplified through moussoneliform daonellas (Daonella, Bivalvia; Triassic). Palontologische Zeitschrift, 75, 51–70.
  • SOKOLOV, D. N. 1908. Ueber Aucellen aus dem Norden und Osten von Siberien. Mémoires de l’Académie Impériale des Sciences de St. Pétersbourg, Série 8, 21, 18 pp.
  • UBUKATA, T. 2005. Theoretical morphology of bivalve shell sculptures. Paleobiology, 31, 643–655.
  • ZAKHAROV, V. A. 1981. Buchiidae and biostratigraphy of the Boreal Upper Jurassic and Neocomian. Trudy Instituta Geologii i Geofiziki, 458, 270. p. [In Russian].
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