Decoupled temporal patterns of evolution and ecology in two post- paleozoic clades

Science

Volumn 281, Issue 5378, 1998, Pages 807-809

  McKinney, Frank K ^a   Lidgard, Scott ^b   Sepkoski Jr , J John ^c   Taylor, Paul D ^d  

^a APPALACHIAN STATE UNIVERSITY   (United States)

^b FIELD MUSEUM OF NATURAL HISTORY   (United States)

^c UNIVERSITY OF CHICAGO   (United States)

^d DEPARTMENT OF LIFE SCIENCES   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

CENOZOIC; ECOLOGY; EVOLUTION; MESOZOIC; PALEOECOLOGY; TEMPORAL VARIATION;

ARTICLE; BIODIVERSITY; CYCLOSTOME; ECOLOGY; EVOLUTION; FOSSIL; NATURAL SELECTION; PRIORITY JOURNAL; SPECIES DIFFERENTIATION; TAXONOMY; TIME;

NASA DISCIPLINE EXOBIOLOGY; NON-NASA CENTER;

ANIMALS; BRYOZOA; EARTH (PLANET); ECOSYSTEM; EVOLUTION; FOSSILS; MARINE BIOLOGY; PALEONTOLOGY;

BRYOZOA; CHEILOSTOMATIDA;

EID: 0032493896     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.281.5378.807     Document Type: Article

References (48)

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11. Counts of individuals are inappropriate for skeletalized colonial organisms because of modularity and fragmentation, and the sizes of sexually mature bryozoan colonies range over several orders of magnitude. Therefore, skeletal mass was taken as an appropriate proxy for abundance or biomass [W. I. Ausich, Ohio J. Sci. 81, 268 (1981); G. Staff, E. N. Powell, R. J. Stanton Jr., H. Cummins, Lethaia 18, 209 (1985)]. We stress that this proxy is potentially subject to taphonomic bias and is strictly empirical. Competitive dominance in the once-living community requires different bases of inference.
12. Counts of individuals are inappropriate for skeletalized colonial organisms because of modularity and fragmentation, and the sizes of sexually mature bryozoan colonies range over several orders of magnitude. Therefore, skeletal mass was taken as an appropriate proxy for abundance or biomass [W. I. Ausich, Ohio J. Sci. 81, 268 (1981); G. Staff, E. N. Powell, R. J. Stanton Jr., H. Cummins, Lethaia 18, 209 (1985)]. We stress that this proxy is potentially subject to taphonomic bias and is strictly empirical. Competitive dominance in the once-living community requires different bases of inference.
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21. T. L. Phillips and R. A. Peppers, Int. J. Coal Geol. 3, 205 (1984); D. W. Krause, Univ. Wyoming Contrib. Geol. Spec. Pap. 3 (1986), pp. 95-117; S. Lidgard and J. B. C. Jackson, Paleobiology 15, 255 (1989); B. E. Berglund, H. J. B. Birks, M. Ralska-Jasiewiczowa, H. E. Wright, Eds., Paleoecological Events During the Last 15,000 Years (Wiley, Chichester, UK, 1996); R. Lupia, P. R. Crane, S. Lidgard, in Biotic Response to Global Change: The Last 145 Million Years, S. J. Culver and P. F. Rawson, Eds. (Chapman & Hall, London, in press).
22. T. L. Phillips and R. A. Peppers, Int. J. Coal Geol. 3, 205 (1984); D. W. Krause, Univ. Wyoming Contrib. Geol. Spec. Pap. 3 (1986), pp. 95-117; S. Lidgard and J. B. C. Jackson, Paleobiology 15, 255 (1989); B. E. Berglund, H. J. B. Birks, M. Ralska-Jasiewiczowa, H. E. Wright, Eds., Paleoecological Events During the Last 15,000 Years (Wiley, Chichester, UK, 1996); R. Lupia, P. R. Crane, S. Lidgard, in Biotic Response to Global Change: The Last 145 Million Years, S. J. Culver and P. F. Rawson, Eds. (Chapman & Hall, London, in press).
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24. T. L. Phillips and R. A. Peppers, Int. J. Coal Geol. 3, 205 (1984); D. W. Krause, Univ. Wyoming Contrib. Geol. Spec. Pap. 3 (1986), pp. 95-117; S. Lidgard and J. B. C. Jackson, Paleobiology 15, 255 (1989); B. E. Berglund, H. J. B. Birks, M. Ralska-Jasiewiczowa, H. E. Wright, Eds., Paleoecological Events During the Last 15,000 Years (Wiley, Chichester, UK, 1996); R. Lupia, P. R. Crane, S. Lidgard, in Biotic Response to Global Change: The Last 145 Million Years, S. J. Culver and P. F. Rawson, Eds. (Chapman & Hall, London, in press).
25. F. K. McKinney and J. B. C. Jackson, Bryozoan Evolution (Unwin Hyman, Boston, 1989).
26. P. D. Taylor and G. P. Larwood, in Extinction and Survival in the Fossil Record, G. P. Larwood, Ed. (Clarendon, Oxford, 1988), pp. 99-119.
27. All bryozoan fragments retained on 0.5-mm and larger screens were picked from 60 entire disaggregated 0.3-to 3.0-kg samples or, where bryozoans were extraordinarily abundant, from subsamples; fragments were sorted on the basis of clade, and total mass for each clade was determined directly or calculated on the basis of subsamples. Species that produce colony fragments typically smaller than 0.5 mm have not been included in most previous studies of bryozoan species diversity [summarized in (13)]. We have excluded such small size fragments from our calculations of relative skeletal mass as well; these fractions are subject to winnowing in many recent bryozoan habitats and are rarely derived from the ecologically dominant taxa. Nonetheless, small colonies of cyclostomes and cheilostomes may be numerous in some environments (E. Håkansson, personal communication). Our data were supplemented by data in O. Berthelsen, Danmarks Geol. Unders. 83, 1 (1962) and A. H. Cheetham, Smithsonian Contrib. Paleobiol. 6, 1 (1971). Some variation in the data inevitably results from variable amounts of cement or of matrix or shell fragments. Cyclostomes tend to have thinner walls than do cheilostomes, and raw cheilostome mass was weighted by 1.26 on the basis of a thin-section determination of the ratio of skeleton to cement plus adherent material in control samples [33 cheilostomes (X̄ = 0.62, SD = 0.147) and 35 cyclostomes (X̄ = 0.51, SD = 0.151) from four representative collections]. Additional "noise" in the data may be due to different taphonomic responses of cyclostome and cheilostome bryozoans in different environments. However, dissolution and abrasion rates of mineralized bryozoans are dependent upon diverse factors that cut across clade assignment [A. M. Smith, C. S. Nelson, P. J. Danaher, Palaeogeogr. Palaeoclimatol. Palaeoecol. 93, 213 (1992); A. M. Smith and C. S. Nelson, in Biology and Palaeobiology of Bryozoans, P. J. Hayward, J. S. Ryland, P. D. Taylor, Eds. (Olsen & Olsen, Fredensborg, Denmark, 1994), pp. 177-180; in Bryozoans in Space and Time, D. P. Gordon, A. M. Smith, J. A. Grant-Mackie, Eds. (National Institute of Water & Atmospheric Research Ltd., Wellington, New Zealand, 1996), pp. 213-226.
28. All bryozoan fragments retained on 0.5-mm and larger screens were picked from 60 entire disaggregated 0.3-to 3.0-kg samples or, where bryozoans were extraordinarily abundant, from subsamples; fragments were sorted on the basis of clade, and total mass for each clade was determined directly or calculated on the basis of subsamples. Species that produce colony fragments typically smaller than 0.5 mm have not been included in most previous studies of bryozoan species diversity [summarized in (13)]. We have excluded such small size fragments from our calculations of relative skeletal mass as well; these fractions are subject to winnowing in many recent bryozoan habitats and are rarely derived from the ecologically dominant taxa. Nonetheless, small colonies of cyclostomes and cheilostomes may be numerous in some environments (E. Håkansson, personal communication). Our data were supplemented by data in O. Berthelsen, Danmarks Geol. Unders. 83, 1 (1962) and A. H. Cheetham, Smithsonian Contrib. Paleobiol. 6, 1 (1971). Some variation in the data inevitably results from variable amounts of cement or of matrix or shell fragments. Cyclostomes tend to have thinner walls than do cheilostomes, and raw cheilostome mass was weighted by 1.26 on the basis of a thin-section determination of the ratio of skeleton to cement plus adherent material in control samples [33 cheilostomes (X̄ = 0.62, SD = 0.147) and 35 cyclostomes (X̄ = 0.51, SD = 0.151) from four representative collections]. Additional "noise" in the data may be due to different taphonomic responses of cyclostome and cheilostome bryozoans in different environments. However, dissolution and abrasion rates of mineralized bryozoans are dependent upon diverse factors that cut across clade assignment [A. M. Smith, C. S. Nelson, P. J. Danaher, Palaeogeogr. Palaeoclimatol. Palaeoecol. 93, 213 (1992); A. M. Smith and C. S. Nelson, in Biology and Palaeobiology of Bryozoans, P. J. Hayward, J. S. Ryland, P. D. Taylor, Eds. (Olsen & Olsen, Fredensborg, Denmark, 1994), pp. 177-180; in Bryozoans in Space and Time, D. P. Gordon, A. M. Smith, J. A. Grant-Mackie, Eds. (National Institute of Water & Atmospheric Research Ltd., Wellington, New Zealand, 1996), pp. 213-226.
29. All bryozoan fragments retained on 0.5-mm and larger screens were picked from 60 entire disaggregated 0.3-to 3.0-kg samples or, where bryozoans were extraordinarily abundant, from subsamples; fragments were sorted on the basis of clade, and total mass for each clade was determined directly or calculated on the basis of subsamples. Species that produce colony fragments typically smaller than 0.5 mm have not been included in most previous studies of bryozoan species diversity [summarized in (13)]. We have excluded such small size fragments from our calculations of relative skeletal mass as well; these fractions are subject to winnowing in many recent bryozoan habitats and are rarely derived from the ecologically dominant taxa. Nonetheless, small colonies of cyclostomes and cheilostomes may be numerous in some environments (E. Håkansson, personal communication). Our data were supplemented by data in O. Berthelsen, Danmarks Geol. Unders. 83, 1 (1962) and A. H. Cheetham, Smithsonian Contrib. Paleobiol. 6, 1 (1971). Some variation in the data inevitably results from variable amounts of cement or of matrix or shell fragments. Cyclostomes tend to have thinner walls than do cheilostomes, and raw cheilostome mass was weighted by 1.26 on the basis of a thin-section determination of the ratio of skeleton to cement plus adherent material in control samples [33 cheilostomes (X̄ = 0.62, SD = 0.147) and 35 cyclostomes (X̄ = 0.51, SD = 0.151) from four representative collections]. Additional "noise" in the data may be due to different taphonomic responses of cyclostome and cheilostome bryozoans in different environments. However, dissolution and abrasion rates of mineralized bryozoans are dependent upon diverse factors that cut across clade assignment [A. M. Smith, C. S. Nelson, P. J. Danaher, Palaeogeogr. Palaeoclimatol. Palaeoecol. 93, 213 (1992); A. M. Smith and C. S. Nelson, in Biology and Palaeobiology of Bryozoans, P. J. Hayward, J. S. Ryland, P. D. Taylor, Eds. (Olsen & Olsen, Fredensborg, Denmark, 1994), pp. 177-180; in Bryozoans in Space and Time, D. P. Gordon, A. M. Smith, J. A. Grant-Mackie, Eds. (National Institute of Water & Atmospheric Research Ltd., Wellington, New Zealand, 1996), pp. 213-226.
30. All bryozoan fragments retained on 0.5-mm and larger screens were picked from 60 entire disaggregated 0.3-to 3.0-kg samples or, where bryozoans were extraordinarily abundant, from subsamples; fragments were sorted on the basis of clade, and total mass for each clade was determined directly or calculated on the basis of subsamples. Species that produce colony fragments typically smaller than 0.5 mm have not been included in most previous studies of bryozoan species diversity [summarized in (13)]. We have excluded such small size fragments from our calculations of relative skeletal mass as well; these fractions are subject to winnowing in many recent bryozoan habitats and are rarely derived from the ecologically dominant taxa. Nonetheless, small colonies of cyclostomes and cheilostomes may be numerous in some environments (E. Håkansson, personal communication). Our data were supplemented by data in O. Berthelsen, Danmarks Geol. Unders. 83, 1 (1962) and A. H. Cheetham, Smithsonian Contrib. Paleobiol. 6, 1 (1971). Some variation in the data inevitably results from variable amounts of cement or of matrix or shell fragments. Cyclostomes tend to have thinner walls than do cheilostomes, and raw cheilostome mass was weighted by 1.26 on the basis of a thin-section determination of the ratio of skeleton to cement plus adherent material in control samples [33 cheilostomes (X̄ = 0.62, SD = 0.147) and 35 cyclostomes (X̄ = 0.51, SD = 0.151) from four representative collections]. Additional "noise" in the data may be due to different taphonomic responses of cyclostome and cheilostome bryozoans in different environments. However, dissolution and abrasion rates of mineralized bryozoans are dependent upon diverse factors that cut across clade assignment [A. M. Smith, C. S. Nelson, P. J. Danaher, Palaeogeogr. Palaeoclimatol. Palaeoecol. 93, 213 (1992); A. M. Smith and C. S. Nelson, in Biology and Palaeobiology of Bryozoans, P. J. Hayward, J. S. Ryland, P. D. Taylor, Eds. (Olsen & Olsen, Fredensborg, Denmark, 1994), pp. 177-180; in Bryozoans in Space and Time, D. P. Gordon, A. M. Smith, J. A. Grant-Mackie, Eds. (National Institute of Water & Atmospheric Research Ltd., Wellington, New Zealand, 1996), pp. 213-226.
31. All bryozoan fragments retained on 0.5-mm and larger screens were picked from 60 entire disaggregated 0.3-to 3.0-kg samples or, where bryozoans were extraordinarily abundant, from subsamples; fragments were sorted on the basis of clade, and total mass for each clade was determined directly or calculated on the basis of subsamples. Species that produce colony fragments typically smaller than 0.5 mm have not been included in most previous studies of bryozoan species diversity [summarized in (13)]. We have excluded such small size fragments from our calculations of relative skeletal mass as well; these fractions are subject to winnowing in many recent bryozoan habitats and are rarely derived from the ecologically dominant taxa. Nonetheless, small colonies of cyclostomes and cheilostomes may be numerous in some environments (E. Håkansson, personal communication). Our data were supplemented by data in O. Berthelsen, Danmarks Geol. Unders. 83, 1 (1962) and A. H. Cheetham, Smithsonian Contrib. Paleobiol. 6, 1 (1971). Some variation in the data inevitably results from variable amounts of cement or of matrix or shell fragments. Cyclostomes tend to have thinner walls than do cheilostomes, and raw cheilostome mass was weighted by 1.26 on the basis of a thin-section determination of the ratio of skeleton to cement plus adherent material in control samples [33 cheilostomes (X̄ = 0.62, SD = 0.147) and 35 cyclostomes (X̄ = 0.51, SD = 0.151) from four representative collections]. Additional "noise" in the data may be due to different taphonomic responses of cyclostome and cheilostome bryozoans in different environments. However, dissolution and abrasion rates of mineralized bryozoans are dependent upon diverse factors that cut across clade assignment [A. M. Smith, C. S. Nelson, P. J. Danaher, Palaeogeogr. Palaeoclimatol. Palaeoecol. 93, 213 (1992); A. M. Smith and C. S. Nelson, in Biology and Palaeobiology of Bryozoans, P. J. Hayward, J. S. Ryland, P. D. Taylor, Eds. (Olsen & Olsen, Fredensborg, Denmark, 1994), pp. 177-180; in Bryozoans in Space and Time, D. P. Gordon, A. M. Smith, J. A. Grant-Mackie, Eds. (National Institute of Water & Atmospheric Research Ltd., Wellington, New Zealand, 1996), pp. 213-226.
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35. The skeletal mass of cyclostomes was 70% in middle Danian and 62% in late Danian.
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41. M. Foote, Palaeontology 34, 461 (1991); Univ. Michigan Mus. Paleontol. Contrib. 28, 101 (1991); Proc. Natl. Acad. Sci. U.S.A. 89, 7325 (1992); Paleobiology 19, 185 (1993); ibid. 21, 273 (1995); Science 274, 1492 (1996).
42. M. Foote, Palaeontology 34, 461 (1991); Univ. Michigan Mus. Paleontol. Contrib. 28, 101 (1991); Proc. Natl. Acad. Sci. U.S.A. 89, 7325 (1992); Paleobiology 19, 185 (1993); ibid. 21, 273 (1995); Science 274, 1492 (1996).
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45. 2 on shell debris in the northern Adriatic off Rovinj, Croatia (F. K. McKinney, unpublished data). The two faunas are qualitatively judged to represent colony size of contemporaneous faunas, and the major change has been an increase in mean size of cheilostome colonies.
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48. Supported by the NSF (DEB 9306729 to S.L.; EAR 9117289 to F.K.M.), U.S.-U.K. Fulbright program (F.K.M.), National Geographic Society (F.K.M.), Petroleum Research Fund of American Chemical Society (F.K.M.), NASA (NAGW-1963 to J.J.S.J.), and Global Change and the Biosphere Programme of the National History Museum/University College London (P.D.T.). We thank S. Hageman, R. Lupia, and two anonymous reviewers for evaluating the manuscript and numerous colleagues who served as guides to field localities.