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Patterns and processes of latest Ordovician graptolite extinction and recovery based on data from South China

  • Chen Xu (a1), Michael J. Melchin (a2), H. David Sheets (a3), Charles E. Mitchell (a4) and Fan Jun-Xuan (a1)...

Abstract

We have studied the pattern of graptolite species turnover during the latest Ordovician mass extinction based on four continuous Ashgillian to earliest Llandovery sections together with data from more than 30 other published sections. The studied sections represent relatively shallow-water and deeper-water belts in the Yangtze Platform region. Using temporally scaled range data, species diversities and extinction and origination probabilities have been calculated using several analytical methods, including a capture-mark-recapture method. We test the statistical significance of these results and the apparent taxonomic selectivity of extinction and origination via Monte Carlo simulations and contingency analysis.

Graptolite species diversity within the Yangtze Platform rose steadily during the late Ashgill, until in the mid-late Paraorthograptus pacificus Chron, when rising extinction risk overtook origination. Diversity dropped to very low levels during the early Hirnantian when extinction probabilities attained significantly elevated rates for a period of 600–900 Ky. The period of high extinction risk was followed immediately by a short period of very high origination probability. A second, short period of high extinction risk occurred at the end of Hirnantian time. The Hirnantian extinction events marked a change from relatively low, steady origination and extinction probabilities to a prolonged period of elevated extinction risk and highly variable origination probability that extended well into the Rhuddanian. Extinction and origination was highly selective during the Hirnantian and favored both the survival and diversification of the Normalograptidae relative to the Dicranograptidae, Diplograptidae, and Orthograptidae.

The main phase of extinction in the latest Rawtheyan and early Hirnantian was coincident with continental glaciation in the Southern Hemisphere. The resulting changes in ocean circulation and oxygenation appear to have almost completely eliminated the preferred habitat for most graptolite species. The Yangtze Platform region, however, may have served as a refugium for many taxa that disappeared earlier in other regions as well as a host site for the initiation of graptolite rediversification. Following the end of the glaciation, conditions favorable for graptolite proliferation were restored but graptolite communities remained unstable for much of the late Hirnantian and early Rhuddanian. Accordingly, the Hirnantian mass extinction appears to have fundamentally altered graptolite species dynamics as well as clade dominance patterns. A full understanding of the history of life requires an expanded, hierarchical theory of evolution that gives to mass extinctions (and other levels of selection) an appropriate role in determining clade and diversity histories.

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Akaike, H. 1973. Information theory and an extension of the maximum likelihood principle, p. 267281. In Petrov, B. N. and Csaki, F. (eds.), Second International Symposium on Information Theory. Akademiai Kiado, Budapest.
Apollonov, M. K., Bandaletov, S. M., and Nikitin, J. F. 1980. The Ordovician–Silurian Boundary in Kazakhstan. “Nauka” Kazakhstan SSR Publishing House, 232 p. (In Russian)
Armstrong, H. A. 1996. Biotic recovery after mass extinction: The role of climate and ocean-state in the post-glacial (Late Ordovician–Early Silurian) recovery of the conodonts, p. 105117. In Hart, M. B. (ed.), Biotic Recovery from Mass Extinction Events. Geological Society Special Publication, 102.
Berry, W. B. N. 1996. Recovery of post-Late Ordovician extinction graptolites: A western North American perspective, p. 291315. In Hart, M. B. (ed.), Biotic Recovery from Mass Extinction Events. Geological Society Special Publication, 102.
Berry, W. B. N., and Wilde, P. 1990. Graptolite biogeography: Implications for palaeogeography and palaeoceanography, p. 129137. In McKerrow, W. S. and Scotese, C. R. (eds.), Palaeozoic Palaeogeography and Biogeography. Geological Society Memoir, 12.
Berry, W. B. N., Wilde, P., and Quinby-Hunt, M. S. 1987. The graptolite habitat: An oceanic non-sulfide low oxygen zone? Bulletin of the Geological Society of Denmark, 35:103113.
Berry, W. B. N., Wilde, P., and Quinby-Hunt, M. S. 1990. Late Ordovician graptolite mass mortality and subsequent early Silurian re-radiation, p. 115123. In Kauffman, E. G. and Walliser, O. H. (eds.), Extinction Events in Earth History. Springer-Verlag, Berlin.
Bottjer, D. J. 2001. Biotic recovery from mass extinctions, p. 202206. In Briggs, D. E. G. and Crowther, P. R. (eds.), Paleobiology II. Blackwell Press, Oxford.
Brenchley, P. J. 2001. Late Ordovician Extinction, p. 220223. In Briggs, D. E. G. and Crowther, P. R. (eds.), Palaeobiology II. Blackwell Press, Oxford.
Brenchley, P. J., Carden, G. A. F., Hints, L., Kaljo, D., Marshall, J. D., Martma, T., Meidla, T., and Nõlvak, J. 2003. High-resolution stable isotope stratigraphy of Upper Ordovician sequences: Constraints on the timing of bioevents and environmental changes associated with mass extinction and glaciation. Geological Society of America Bulletin, 115:89104.
Brenchley, P. J., Marshall, J. D., Carden, G. A. F., Robertson, D. B. R., Long, D. G. F., Meidla, T., Hints, L., and Anderson, T. F. 1994. Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period. Geology, 22:295298.
Brett, C. E., Ivany, L. C., and Schopf, K. M. 1996. Coordinated stasis: An overview. Palaeogeography, Palaeoclimatology, and Palaeoecology, 127:120.
Burnham, K. P., and Anderson, D. R. 1998. Model Selection and Inference: A Practical Information-Theoretic Approach. Springer, New York, 353 p.
Chen, Shu-e, An-dong, Xu, and Han-jun, Chen. 1994. Ashgillian graptolite strata (Wufeng Formation) of Fucheng, Nanzheng, Southern Shaanxi, p. 174179. In Chen Xu, B.-D.Erdtmann, , and Yu-nan, Ni (eds.), Graptolite Research Today. Nanjing University Press, Nanjing.
Chen, Xu. 1984. Influence of the Late Ordovician glaciation on basin configuration of the Yangtze Platform in China. Lethaia, 17:5159.
Chen, Xu, and Yao-kun, Lin. 1978. Lower Silurian graptolites from Tongzi, northern Guizhou. Memoir of Nanjing Institute of Geology and Palaeontology, Academia Sinica, 12:1106. (In Chinese with English summary)
Chen, Xu, Melchin, M. J., Jun-xuan, Fan, and Mitchell, C. E. 2003. The Ashgillian graptolite fauna of the Yangtze regions and biogeographical distribution of diversity in the latest Ordovician. Bulletin de la Société Géologique de France, 175:141148.
Chen, Xu, Ji-jin, Li, Liang-yu, Geng, Jin-yu, Qiu, Yu-nan, Ni, and Xue-chang, Yang. 1988. Silurian of Lower Yangtze Region, Jiangsu, p. 127168. In Academy of Geological Sciences, Jiangsu Bureau of Petroleum Prospecting and Nanjing Institute of Geology and Palaeontology, Academia Sinica (eds.), Sinian-Triassic Biostratigraphy of the Lower Yangtze Peneplatform in Jiangsu Region. Nanjing University Press, Nanjing. (In Chinese)
Chen, Xu, Jun-xuan, Fan, Melchin, M. J., and Mitchell, C. E. 2004a. Graptolites of the Hirnantian Substage (latest Ordovician) from the Upper Yangtze Region, China. Palaeontology, 48:235280.
Chen, Xu, Jia-yu, Rong, Jun-xuan, Fan, Ren-bin, Zhan, Mitchell, C. E., Harper, D. A. T., Melchin, M. J., and Xiao-feng, Wang. 2004b. A final report on the GSSP candidate of the Hirnantian Stage. Report to the Subcommission on Ordovician Stratigraphy. http://seis.natsci.csulb.edu/ord2/Documents/Wangjiawan_GSSP.pdf.
Chen, Xu, Jia-yu, Rong, Jun-xuan, Fan, Ren-bin, Zhan, Yuan-dong, Zhang, Zong-zhe, Wang, Rong-yu, Li, Yi, Wang, Mitchell, C. E., and Harper, D. A. T. 2000a. Biostratigraphy of the Hirnantian Substage from the Yangtze region. Journal of Stratigraphy, 24(1):169175. (In Chinese with English abstract)
Chen, Xu, Jia-yu, Rong, Mitchell, C. E., Harper, D. A. T., Jun-xuan, Fan, Ren-bin, Zhan, Yuan-dong, Zhang, Rong-yu, Li, and Yi, Wang. 2000b. Late Ordovician to earliest Silurian graptolite and brachiopod biozonation from the Yangtze region, South China with a global correlation. Geological Magazine, 137:623650.
Chen, Xu, Jia-yu, Rong, Mitchell, C. E., Harper, D. A. T., Jun-xuan, Fan, Ren-bin, Zhan, Yuan-dong, Zhang, Zhi-hao, Wang, Zhong-zhe, Wang, and Yi, Wang. 1999. Stratigraphy of the Hirnantian Substage from Wangjiawan, Yichang, W. Hubei and Honghuayuan, Tongzi, N. Guizhou, China, p. 233236. In Kraft, P. and Fatka, O. (eds.), Quo vadis Ordovician? Acta Universitatis Carolinae–Geologica, 43. Univerzita Karlova v Praze, Praha.
Connolly, S. R., and Miller, A. I. 2001. Joint estimation of sampling and turnover rates from fossil databases: Capture-mark-recapture methods revisited. Paleobiology, 27:751767.
Cooch, E., and White, G. 2001. Program Mark: Analysis of data from Marked Individuals. Online introductory text to support Mark. http://canuck.dnr.cornell.edu/mark.
Cooper, R. A. 1998. Toward a general model for the depth ecology of graptolites, p. 161163. In Gutiérrez-Marco, J. C. and Rábano, I. (eds.), Proceedings of the Sixth International Graptolite Conference and the 1998 Field Meeting of the International Subcommission on Silurian Stratigraphy (ICS-IUGS). Instituto Tecnológico Geominero de España, Temas Geológico-Mineros, 23.
Cooper, R. A. 1999. The Ordovician time scale—calibration of graptolite and conodont zones, p. 14. In Kraft, P. and Fatka, O. (eds.), Quo vadis Ordovician? Acta Universitatis Carolinae–Geologica, 43. Univerzita Karlova v Praze, Praha.
Cooper, R. A., and Sadler, P. M. 2004. Ordovician System, p. 165187. In Gradstein, F. M., Ogg, J. G., and Smith, A. G. (eds.), A Geologic Time Scale. Cambridge University Press, Cambridge.
Darwin, C. 1859. On the Origin of Species by Means of Natural Selection. John Murray, London, 490 p.
Davies, K. A. 1929. Notes on the graptolite faunas in the Upper Ordovician and Lower Silurian. Geological Magazine, 66:127.
Elles, G. L., and Wood, E. M. R. 1906. A Monograph of British Graptolites. Palaeontographical Society, London, 5:181216.
Elles, G. L., and Wood, E. M. R. 1907. A Monograph of British Graptolites. Palaeontographical Society, London, 6:217272.
Fan, Jun-xuan. 2001. Late Ordovician to earliest Silurian quantitative biostratigraphy in the Yangtze region. Unpublished Ph.D. dissertation, Nanjing Institute of Geology and Palaeontology, Nanjing, 188 p.
Fan, Jun-xuan, Xu, Chen, and Yuan-dong, Zhang. 2000. Quantitative biostratigraphic study of Yangtze Platform—with the designing of SinoCor 2.0, a software program for graphic correlation. Palaeontology Down Under 2000, Geological Society of Australia Abstracts, 61:31.
Finney, S. C. 2001. Species diversification during mass extinction: Graptolites in the Late Ordovician. Geological Society of America Annual Meeting, Boston, Massachusetts, Abstracts with Programs, 36:A-213.
Finney, S. C., and Berry, W. B. N. 1997. New perspectives on graptolite distributions and their use as indicators of platform margin dynamics. Geology, 25:919922.
Finney, S. C., Berry, W. B. N., Cooper, J. D., Ripperdan, R. L., Sweet, W. C., Jacobson, S. R., Soufiane, A., Achab, A., and Noble, P. J. 1999. Late Ordovician mass extinction: A new perspective from stratigraphic sections in central Nevada. Geology, 27:215218.
Foote, M. 2000. Origination and extinction components of taxonomic diversity: General problems, p. 74102. In Erwin, D. H. and Wing, S. L. (eds.), Deep Time: Paleobiology's Perspective. The Paleontological Society, Lawrence, Kansas.
Foote, M. 2001. Inferring temporal patterns of preservation, origination, and extinction from taxonomic survivorship analysis. Paleobiology, 27:602630.
Fortey, R. A., Harper, D. A. T., Ingham, J. K., Owen, A. W., Parkes, M. A., Rushton, A. W. A., and Woodcock, N. H. 2000. A revised correlation of the Silurian rocks in the British Isles. Geological Society, London, Special Report, 24:183.
Fu, Li-pu, and Li-shen, Song. 1986. Stratigraphy and Palaeontology of Silurian in Ziyang Region (Transitional Belt). Bulletin of Xi'an Institute of Geology and Mineral Resources, Chinese Academy of Geological Sciences, 14. Geological Publishing House, Beijing, 198 p. (In Chinese with English summary)
Ge, Mei-yu. 1984. The Graptolite Fauna of the Ordovician–Silurian Boundary Section in Yuqian, Zhejiang, p. 389454. In Nanjing Institute of Geology and Palaeontology (ed.), Stratigraphy and Palaeontology of Systemic Boundaries in China, 1. Ordovician–Silurian Boundary. Anhui Science and Technology, Hefei.
Goldman, D., and Bergström, S. M. 1997. Late Ordovician graptolites from the North American midcontinent. Palaeontology, 40:9651010.
Hall, J. 1865. Figures and Descriptions of Canadian Organic Remains. Decade II, Graptolites of the Quebec Group. Geological Survey of Canada, Dawson Brothers, Montreal, 151 p.
Hallam, A., and Wignall, P. B. 1997. Latest Ordovician extinctions: One disaster after another, p. 3961. In Hallam, A. and Wignall, P. B. (eds.), Mass Extinctions and their Aftermath. Oxford University Press, Oxford.
Harper, D. A. T., and Jia-yu, Rong. 1995. Patterns of change in the brachiopod faunas through the Ordovician–Silurian interface. Modern Geology, 20:83100.
Hopkinson, J. 1871. On Dicellograptus, a new genus of graptolites. Geological Magazine, 8:2026.
Jeppsson, L. 1990. An oceanic model for lithological and faunal changes tested on the Silurian record. Journal of the Geological Society (London), 147:663674.
Jeppsson, L. 1998. Silurian oceanic events: Summary of general characteristics, p. 239257. In Landing, E. and Johnson, M. E. (eds.), Silurian cycles: Linkages of dynamic stratigraphy with atmospheric, oceanic and tectonic changes. New York State Museum Bulletin, 491.
Kauffman, E. G., and Erwin, D. H. 1995. Surviving mass extinctions. Geotimes, 14:1417.
Kauffman, E. G., and Harries, P. J. 1996. The importance of crisis progenitors in recovery from mass extinction, p. 1539. In Hart, M. B. (ed.), Biotic Recovery from Mass Extinction Events. Geological Society Special Publication, 102.
Koren', T. N. 1991. Evolutionary crisis of the Ashgill graptolites, p. 157164. In Barnes, C. R. and Williams, S. H. (eds.), Advances in Ordovician geology. Geological Survey of Canada Paper, 90–9.
Koren', T. N., and Bjerreskov, M. 1999. The generative phase and the first radiation event in the Early Silurian monograptid history. Palaeogeography, Palaeoclimatology, Palaeoecology, 154:39.
Koren', T. N., and Nitikin, I. F. 1982. Graptolites about the Ordovician–Silurian boundary. Comments on Report No. 45. Ordovician–Silurian Boundary Working Group (unpublished).
Koren', T. N., and Sobolevskaya, R. F. 2004. The Hirnantian Stage boundary marked by the first appearance of Normalograptus extraordinarius (Sobolevskaya), Mirny Creek, Omulev Mountains, northeast Russia. Report to the Subcommission on Ordovician Stratigraphy. http://seis.natsci.csulb.edu/ord2/Documents/Mirny_Creek_GSSP.pdf.
Koren', T. N., Oradovskaya, M. M., Pylma, L. J., Sobolev-skaya, R. F., and Chugaeva, M. N. 1983. The Ordovician and Silurian boundary in the north–east of the USSR. Trudy Mezhvedomstvennogo Stratigraficheskogo Komiteta SSSR, 11. Nauka, Leningrad, 205 p. (In Russian)
Lapworth, C. 1873. On an improved classification of the Rhabdopora, Pt. I. Geological Magazine, 10:500504.
Lapworth, C. 1876. Page 1–164. In Armstrong, J., Young, J., and Robertson, D. (eds.), Catalogue of western Scottish fossils. Prepared for the meeting of the British Association in Glasgow, 1876.
Lapworth, C. 1877. On the graptolites from County Down. Systematic lists illustrative of the flora, palaeontology and archaeology of the north of Ireland by the members of the Belfast Naturalists Field Club. Volume 1 (Appendix), 4:126144.
Lebreton, J.-D., Burnham, K. P., Clobert, J., and Anderson, D. R. 1992. Modeling survival and testing biological hypotheses using marked animals: A unified approach with case studies. Ecological Monographs, 62:67118.
Legrand, P. 1987. Modo de desarrollo del suborden Diplograptina (Graptolithina) en el Ordovícico Superior y en el Silurico. Revista Espanola de Paleontologia, 2:5964.
Lenz, A. C., and McCracken, A. D. 1982. The Ordovician–Silurian boundary, northern Canadian Cordillera: Graptolite and conodont correlation. Canadian Journal of Earth Sciences, 19:13081322.
Li, Ji-jin. 1984a. Graptolites across the Ordovician–Silurian Boundary from Jingxian, Anhui, p. 309370. In Nanjing Institute of Geology and Palaeontology (ed.), Stratigraphy and Palaeontology of Systemic Boundaries in China, 1. Ordovician–Silurian Boundary. Anhui Science and Technology, Hefei.
Li, Ji-jin. 1984b. Graptolites from the Xinling Formation (Upper Ordovician) of South Anhui. Memoirs of Nanjing Institute of Geology and Palaeontology, Academia Sinica, 20:145194. (In Chinese with English abstract)
Li, Zi-ming, and Da-qing, Li. 1985. Appendispinograptus, a new subgenus of Climacograptus. Earth Sciences–Journal of Wuhan College of Geology, 10:3542. (In Chinese with English abstract)
Liu, Di-rong, Xu, Chen, and Tai-rong, Zhang. 1964. Early Paleozoic rocks of Nanjiang, northern Sichuan. Memoir of the Nanjing Institute of Geology and Palaeontology, Academia Sinica, 1:161170.
Liu, Yi-ren, and Han-ying, Fu. 1984. Graptolites from the Wufeng Formation (Upper Ordovician) of Anhui, Hunan. Acta Palaeontologica Sinica, 23:642648. (In Chinese with English abstract)
Loydell, D. K. 1994. Early Telychian changes in graptoloid diversity and sea level. Geological Journal, 29:355368.
Melchin, M. J., and Holmden, C. 2000. Carbon isotope stratigraphy of the mid-Ashgill (Late Ordovician) to Lower Telychian (Early Silurian) of the Cape Phillips Formation, central Canadian Arctic Islands. Palaeontology Down Under 2000, Geological Society of Australia Abstracts, 61:166.
Melchin, M. J., and Mitchell, C. E. 1991. Late Ordovician extinction in the Graptoloidea, p. 5978. In Barnes, C. R. and Williams, S. H. (eds.), Advances in Ordovician geology. Geological Survey of Canada Paper, 90–9.
Melchin, M. J., Cooper, R. A., and Sadler, P. M. 2004. Silurian System. In Gradstein, F. M., Ogg, J. G., and Smith, A. G. (eds.), A Geologic Time Scale. Cambridge University Press, Cambridge.
Melchin, M. J., Koren', T. N., and Storch, P. 1998. Global diversity and survivorship patterns of Silurian Graptoloids, p. 165182. In Landing, E. and Johnson, M. E. (eds.), Silurian cycles: Linkages of dynamic stratigraphy with atmospheric, oceanic and tectonic changes. New York State Museum Bulletin, 491.
Melchin, M. J., McCracken, A. D., and Oliff, F. J. 1991. The Ordovician–Silurian boundary on Cornwallis and Truro islands, Arctic Canada: Preliminary data. Canadian Journal of Earth Sciences, 28:18541862.
Mitchell, C. E. 1987. Evolution and phylogenetic classification of the Diplograptacea. Palaeontology, 30:353405.
Mitchell, C. E. 1990. Directional graptolite macroevolution of the diplograptacean graptolites: A product of astogenetic heterochrony and directed speciation, p. 235264. In Taylor, P. D. and Larwood, G. P. (eds.), Major evolutionary radiations. Systematics Association (special volume), 42.
Mu, En-zhi. 1954. On the Wufeng Shale. Acta Palaeontologica Sinica, 2(2):153170. (In Chinese)
Mu, En-zhi. 1963. On the complication of graptolite rhabdosome. Acta Palaeontologica Sinica, 11:346377. (In Chinese with English summary)
Mu, En-zhi, and Yao-kun, Lin. 1984. Graptolites from the Ordovician–Silurian boundary sections of Yichang area, W. Hubei, p. 4582. In Nanjing Institute of Geology and Palaeontology (ed.), Stratigraphy and Palaeontology of Systemic Boundaries in China, 1. Ordovician–Silurian Boundary. Anhui Science and Technology, Hefei.
Mu, En-zhi, and Yu-nan, Ni. 1983. Uppermost Ordovician and Lowermost Silurian graptolites from the Xainza area of Xizang (Tibet) with discussion on the Ordovician–Silurian boundary. Palaeontologia Cathyana, 1:151179.
Mu, En-zhi, Zhao-ling, Zhu, Jun-yuan, Chen, and Jia-yu, Rong. 1978. Ordovician near Shuanghe, Changning, Sichuan. Acta Stratigraphica Sinica, 2(2):105122. (In Chinese)
Mu, En-zhi, Zhao-ling, Zhu, Yao-kun, Lin, and Hong-ji, Wu. 1984. The Ordovician–Silurian boundary in Yichang, Hubei. Stratigraphy and palaeontology of systemic boundaries in China, p. 1544. In Nanjing Institute of Geology and Palaeontology (ed.), Stratigraphy and Palaeontology of Systemic Boundaries in China, 1. Ordovician–Silurian Boundary. Anhui Science and Technology, Hefei.
Mu, En-zhi, Yi-yuan, Qian, Xu, Chen, Yi-gang, Wang, and Xi-ping, Zou. 1965. Lower Paleozoic strata and the fossil atlas from Emeishan, Chengkou and Weiyuan, Sichuan. Nanjing Institute of Geology and Palaeontology, Academia Sinica and Sichuan Bureau of Petroleum, 50 p. (In Chinese)
Mu, En-zhi, Ji-jin, Li, Mei-yu, Ge, Xu, Chen, Yao-kun, Lin, and Yu-nan, Ni. 1993. Upper Ordovician Graptolites of central China Region. Palaeontologia Sinica, B29:1393. (In Chinese with English summary)
Owen, A. W., Harper, D. A. T., and Jia-yu, Rong. 1991. Hirnantian trilobites and brachiopods in space and time, p. 179190. In Barnes, C. R. and Williams, S. H. (eds.), Advances in Ordovician Geology. Geological Survey of Canada Paper, 90–9.
Perner, J. 1895. Studie o Ceskych Graptolitech II. Leipzig, Prague, 52 p.
Pollock, K. H., Nichols, J. D., Brownie, C., and Hines, J. E. 1990. Statistical inference for capture-recapture experiments. Wildlife Monographs, 107:197.
Pradel, R. 1996. Utilization of capture-mark-recapture for the study of recruitment and population growth rate. Biometrics, 52:703709.
Příbyl, A. 1949. Revision of the Diplograptidae and Glossograptidae of the Ordovician of Bohemia. Bulletin Internationale de l'Académie tchèque des Sciences, 50:151.
Raup, D. M. 1991. Extinction: Bad Genes or Bad Luck? W.W. Norton, New York, 210 p.
Rickards, R. B. 1988. Graptolite faunas at the base of the Silurian, p. 345350. In Cocks, L. R. M. and Rickards, R. B. (eds.), A global analysis of the Ordovician–Silurian boundary. Bulletin of the British Museum of Natural History (Geology), 43.
Rickards, R. B. 2002. The graptolitic age of the type Ashgill Series (Ordovician), Cumbria, UK. Proceedings of the Yorkshire Geological Society, 54:116.
Rickards, R. B., and Wright, A. J. 2002. Lazarus taxa, refugia and relict faunas: Evidence from the graptolites. Journal of the Geological Society (London), 159:14.
Rong, Jia-yu. 1984. Distribution of the Hirnantia fauna and its meaning, p. 101112. In Bruton, D. L. (ed.), Aspects of the Ordovician System. Palaeontological Contributions from the University of Oslo, 295.
Rong, Jia-yu, Xu, Chen, Harper, D. A. T., and Mitchell, C. E. 1999. Proposal of a GSSP candidate section in the Yangtze platform region, S. China, for a new Hirnantian boundary stratotype. Acta Universitatis Carolinae, Geologica, 43:7780.
Ruedemann, R. 1947. Graptolites of North America. Geological Society of America Memoir, 19, 652 p.
Sadler, P. M. 2001. Constrained Optimization Approaches to the Paleobiologic Correlation and Seriation Problems: A User's Guide and Reference Manual to the CONOP Program Family. Version 6.1. University of California, Riverside, 159 p.
Schaub, M., Pradel, R., Jenni, L., and Lebreton, J.-D. 2001. Migrating birds stop over longer than usually thought: An improved capture-re-capture analysis. Ecology, 82:852859.
Shaw, A. B. 1964. Time in Stratigraphy. McGraw-Hill, New York, 365 p.
Sheehan, P. M. 1996. A new look at ecologic evolutionary units (EEUs). Palaeogeography, Palaeoclimatology, Palaeoecology, 127:2132.
Sheehan, P. M. 2001. The Late Ordovician mass extinction. Annual Review of Earth and Planetary Sciences, 29:331364.
Signor, P. W., and Lipps, J. H. 1982. Sampling bias, gradual extinction patterns and catastrophes in the fossil record. Geological Society of America Special Paper, 190:291296.
Sokal, R. R., and Rohlf, F. J. 1994. Biometry. The Principles and Practice of Statistics in Biological Research (third edition). W.H. Freeman, New York, 880 p.
Sobolevskaya, R. F. 1974. New Ashgill graptolites in the middle flow basin of the Kolyma river, p. 6371. In Obut, A. M. (ed.), Graptolites of the USSR. Nauka, Siberian Branch, Novosibirsk. (In Russian)
Stanley, S. M., and Yang, X. 1994. A double mass extinction at the end of the Paleozoic era. Science, 266:13401344.
Stewart, S., and Mitchell, C. E. 1997. Anticostia, a distinctive new Late Ordovician “glyptograptid” (Diplograptacea, Graptoloidea) based on three-dimensionally preserved specimens from Anticosti Island, Quebec. Canadian Journal of Earth Sciences, 34:215228.
Underwood, C. J., Crowley, S. F., Marshall, J. D., and Brenchley, P. J. 1997. High-resolution carbon isotope stratigraphy of the basal Silurian Stratotype (Dob's Linn, Scotland) and its global correlation. Journal of the Geological Society (London), 154:709718.
Vrba, E. 1985. Environment and evolution: Alternative causes of the temporal distribution of evolutionary events. South African Journal of Science, 81:229236.
Wang, Kun, Chatterton, B. D. E., and Yang, Wang. 1997. An organic carbon isotope record of Late Ordovician to Early Silurian marine sedimentary rocks, Yangtze Sea, South China: Implications for CO2 changes during the Hirnantian glaciation. Palaeogeography, Palaeoclimatology, Palaeoecology, 132:147158.
White, G. 2001. Program MARK help files. http://www.cnr.colostate.edu/~gwhite/mark/mark.html.
Williams, S. H. 1983. The Ordovician–Silurian Boundary graptolite fauna of Dob's Linn, southern Scotland. Palaeontology, 26:605630.
Yu, Jian-hai, Yi-ting, Fang, Si-jing, Liang, and Hui-bao, Liu. 1984. Boundary between Ordovician and Silurian from Wuning, Jiangxi. Journal of Nanjing University (Nature and Sciences), 20(3):533542. (In Chinese with English abstract)
Yu, Jian-hua, Yi-ting, Fang, and Da-liang, Zhang. 1986. The Ordovician–Silurian Boundary in Xixiang, S. Shaanxi. Journal of Nanjing University (Nature and Sciences), 22(2):475488. (In Chinese with English abstract)
Zalasiewicz, J. A., Rushton, A. W. A., and Owen, A. W. 1995. Late Caradoc graptolite faunal gradients across the Iapetus Ocean. Geological Magazine, 132:611617.
Zhang, Quan-zhong, and Shi-ding, Jiao. 1985. New advance of the Silurian of Tangshan area, Nanjing. Bulletin of Nanjing Institute of Geology and Mineral Resource, 6(2):97111. (In Chinese)
Zhang, Quan-zhong, Hong-an, Chou, Shi-ding, Jiao, Xiao-mei, Xu, and Pei-xia, Guo. 1966. Ordovician rocks of Hexian, Anhui. Journal of Stratigraphy, 1(1):4764. (In Chinese)
Zhang, Wen-tang, Han-kui, Xu, Xu, Chen, Jun-yuan, Chen, Ke-xing, Yuan, Yao-kun, Lin, and Jun-geng, Wang. 1964. Ordovician of northern Guizhou, p. 3378. In Nanjing Institute of Geology and Palaeontology (ed.), Palaeozoic Rocks from Northern Guizhou. Nanjing Institute of Geology and Palaeontology, Nanjing. (In Chinese)
Zhu, Zhao-ling, Mei-yu, Ge, Han-kui, Xu, Ke-xing, Yuan, Yingkai, Liu, Yu-zhong, Li, Liang-yu, Su, Ting-gui, He, Gui-xi, Wang, Xizhang, Li, Zuo-gui, Miao, Chun-fa, Ma, and Cai-shun, Li. 1977. Early Paleozoic Rocks from Chengkou area of Sichuan. Stratigraphy and Palaeontology, 5:164. (In Chinese)

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