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Dinosaur Monophyly and a New Class of Vertebrates

Abstract

TRADITIONALLY dinosaurs are classified as two or three separate, independent groups of reptiles in the Subclass Archosauria. But evidence from bone histology, locomotor dynamics, and predator/prey ratios strongly suggest that dinosaurs were endotherms with high aerobic exercise metabolism, physiologically much more like birds and cursorial mammals than any living reptiles1–8. Recently Ostrom has argued forcefully that birds are direct descendants of dinosaurs and inherited high exercise metabolism from dinosaurs1,8. Here we present evidence that dinosaurs are a single, monophyletic group, and that the key advancements of endothermy and high exercise metabolism are justification for removing dinosaurs from the Reptilia and placing them with birds in a new class, the Dinosauria.

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References

  1. Ostrom, J. H., Q. Rev. Biol. (in the press, 1974).

  2. Bakker, R. T., in Perspectives of Biophysical Ecology (edit. by Gates, D., and Schmerl, R. B.) (New York, in the press).

  3. Enlow, D. H., and Brown, S. O., Tex. J. Sci., 2, 186 (1957).

    Google Scholar 

  4. Currey, J. D., Palaeontology, 5, 238 (1962).

    Google Scholar 

  5. Ricqles, A., Annls. Paleont., 54, 9 (1968).

    Google Scholar 

  6. Bakker, R. T., Evolution, 25, 363 (1971).

    Article  Google Scholar 

  7. Bakker, R. T., Nature, 238, 81 (1972).

    Article  ADS  Google Scholar 

  8. Ostrom, J. O., Nature, 242 136 (1973).

    Article  ADS  Google Scholar 

  9. Bonaparte, J. F., Proc. Pap. 2nd Gond. Symp. S. Afr., 665 (Council for Scientific and Industrial Research, Pretoria, 1972).

    Google Scholar 

  10. Bonaparte, J. F., Op. lilloana, 22, 183 (1971).

    Google Scholar 

  11. Casamiquela, R. M., Ameghiniana, 4, 47 (1967).

    Google Scholar 

  12. Reig, O. A., Ameghiniana, 3, 3 (1963).

    Google Scholar 

  13. Romer, A. S., Breviora, 389, 1 (1972).

    Google Scholar 

  14. Thulborn, R. A., Nature, 234, 75 (1971).

    Article  ADS  Google Scholar 

  15. Cruickshank, A. R., in Studies in Vertebrate Evolution (edit. by Joysey, K. A., and Kemp, T. S.) (Oliver and Boyd, Edinburgh, 1972).

    Google Scholar 

  16. Young, C. C., Mem. Inst. vertebr. Paleont. Peking, 10, 15 (1973).

    Google Scholar 

  17. Walker, A. D., Phil. Trans. R. Soc., B, 244, 103 (1961).

    Google Scholar 

  18. Walker, A. D., Phil. Trans. R. Soc., B, 248, 53 (1964).

    Article  Google Scholar 

  19. Walker, A. D., Phil. Trans. R. Soc., B, 257, 323 (1970).

    Article  Google Scholar 

  20. Kuhn, O., in Die Saurier der Deutschen Trias (Verglag Oeben, München, 1971).

    Google Scholar 

  21. Romer, A. S., in Vertebrate Paleontology (University of Chicago Press, Chicago, 1967).

    Google Scholar 

  22. Charig, A. J., Attridge, J., and Crompton, A. W., Proc. Linn. Soc. Lond., 176, 197 (1965).

    Article  Google Scholar 

  23. Romer, A. S., Breviora, 395, 1 (1972).

    Google Scholar 

  24. Charig, A. J., in Studies in Vertebrate Evolution (edit. by Joysey, K., and Kemp, T.) (Oliver and Boyd, Edinburgh, 1972).

    Google Scholar 

  25. Sawin, H. J., J. Paleont., 21, 201 (1947).

    Google Scholar 

  26. Huene, F. von, in Die fossilen Reptilien des Südamerikanischen Gondwanalandes (C. H. Beck'sche Verlagsbuchhandlang, München, 1935–1942).

    Google Scholar 

  27. Soergel, W., in Die Fahrten der Chirotheria (Jena, 1926).

    Google Scholar 

  28. Krebs, B., Schweiz. Palaeont. Abh., 81, 1 (1965).

    Google Scholar 

  29. Galton, P. M., Arnoldia, 15, 1 (1971).

    Google Scholar 

  30. Galton, P. M., Lethaia, 4, 453 (1971).

    Article  Google Scholar 

  31. Charig, A. J., and Crompton, A. W., Boonstra Commemorative Vol. (Cape Town, in the press).

  32. Hughes, B., S. Afr. J. Sci., 59, 221 (1963).

    Google Scholar 

  33. Sill, W., Bull. Mus. Comp. Zool. Harv. (in the press).

  34. Bonaparte, J. F., Zoo. J. Linn. Soc., 48, 471 (1969).

    Article  Google Scholar 

  35. Huene, F. von, Paläont. Z., 16, 145 (1942).

    Article  Google Scholar 

  36. Raath, M. A., Arnoldia, 28, 1 (1969).

    Google Scholar 

  37. Cott, H. B., Trans. zool. Soc. Lond., 29, 211 (1961).

    Article  Google Scholar 

  38. Colbert, E. H., Amer. Mus. Novitates, 2405, 1 (1970).

    Google Scholar 

  39. Galton, P. M., Paläont. Z., 47, 229 (1973).

    Article  Google Scholar 

  40. Galton, P. M., Bull. Br. Mus. nat. Hist., A, 25, 1 (1974).

    Google Scholar 

  41. Bakker, R. T., Physiologist, Lond., 15, 3 (1972).

    Google Scholar 

  42. Romer, A. S., Breviora, 378, 1 (1971).

    Google Scholar 

  43. Romer, A. S., Breviora, 394, 1 (1972).

    Google Scholar 

  44. Thulborn, R. A., Palaeontology, 13, 414 (1970).

    Google Scholar 

  45. Galton, P. M., J. Paleont., 45, 781 (1971).

    Google Scholar 

  46. Ride, W. D., Syst. Ass. Pub., 3, 33 (1959).

    Google Scholar 

  47. Galton, P. M., Lethaia, 6, 67 (1973).

    Article  Google Scholar 

  48. Galton, P. M., Evolution, 24, 448 (1970).

    Article  Google Scholar 

  49. Walker, A. D., Nature, 237, 257 (1972).

    Article  ADS  Google Scholar 

  50. Ostrom, J. H., K. ned. Akad. v. Wet., B, 75, 289 (1972).

    Google Scholar 

  51. Dunson, W. A., Am. J. Physiol., 216, 995 (1965).

    Google Scholar 

  52. De Beer, G., in Archaeopteryx lithographica (British Museum (Natural History), London, 1954).

    Google Scholar 

  53. Heilmann, G., in The Origin of Birds (D. Appleton and Co., New York, 1927).

    Google Scholar 

  54. Ostrom, J. H., Bull. Peabody Mus. nat. Hist., 35 (1970).

  55. Ostrom, J. H., Bull Peabody Mus. nat. Hist., 30 (1969).

Download references

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BAKKER, R., GALTON, P. Dinosaur Monophyly and a New Class of Vertebrates. Nature 248, 168–172 (1974). https://doi.org/10.1038/248168a0

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  • DOI: https://doi.org/10.1038/248168a0

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