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Letters to Nature
Nature 384, 157 - 158 (14 November 1996); doi:10.1038/384157a0

A Pikaia-like chordate from the Lower Cambrian of China

D.-G. Shu*, S. Conway Morris & X.-L. Zhang*

*Department of Geology, Northwest University, Xi'an, 710069, People's Republic of China
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK

THE earliest evolution of the chordates and their relationships with other deuterostomes remains controversial1–3. Rejuvenation of interest in the areas of molecular phylogeny4 and developmental genetics5–7 has not been matched by new insights from the fossil record, which for the Lower and Middle Cambrian remains exceptionally sparse. The supposed chordate Emmonsaspis 8 has been shown to be a frond-like fossil9, and phosphatic sclerites of hadimopanellids, once compared with vertebrate dermal armour10,11, are now known to be derived from the cuticle of protostome palaeoscolecidan worms12,13. Other fragmentary material of supposed scales is even more dubious14. The best-known candidate in this thin roster remains the Burgess Shale chordate Pikaia 15. Here we report a single specimen of a Lower Cambrian chordate, Cathaymyrus diadexus, new genus and species, that is similar to Pikaia but predates it by about 10 million years (Myr). Important features of this new specimen are structures interpreted as pharyngeal gill slits. The evolution of chordates was an integral part of the first stages of the Cambrian 'explosion', and steps to craniates with neural crest were probably achieved by the Middle Cambrian.

  1. Bone, Q. J. Linn. Soc. (Zool.) 44, 252−269 (1960).
  2. Jollie, M. Zool. J. Linn. Soc. 75, 167−180 (1982). | ISI |
  3. Jefferies, R. P. S., Brown, N. A. & Daley, P. E. J. Acta Zool. Stockh. 77, 101−122 (1996).
  4. Wada, H. & Satoh, N. Proc. Natl Acad. Sci. USA 91, 1801−1804 (1994). | PubMed | ChemPort |
  5. Satoh, N. & Jeffery, W. R. Trends Genet. 11, 354−359 (1995). | Article | PubMed | ISI | ChemPort |
  6. Holland, P. W. H. & Garcia-Fernandez, J. Dev. Biol. 173, 382−395 (1996). | Article | PubMed | ISI | ChemPort |
  7. Holland, P. W. H., Koschorz, B., Holland, L. Z. & Herrmann, B. G. Development 121, 4283−4291 (1995). | PubMed | ISI | ChemPort |
  8. Durham, J. W. Prac. N. Am. Paleont. Conv. H, 1101−1132 (1971).
  9. Conway Morris, S. Palaeontology 36, 593−635 (1993).
  10. van den Boogaard, M. Scr. Geol. 90, 1−12 (1989).
  11. Märss, T. Eesti NSV Tead. Akad. Toim. Geol. 37, 10−17 (1988).
  12. Müller, K. J. & Hinz-Schallreuter, I. Palaeontology 36, 549−592 (1993).
  13. Conway Morris, S. Zool. J. Linn. Soc. (in the press).
  14. Howell, B. F. Bull. Geol. Soc. Am. 48, 1147−1210 (1937).
  15. Conway Morris, S. in Atlas of the Burgess Shale (ed. Conway Morris, S.) 26 (Palaeontological Association, London, 1982).
  16. Chen, J.-Y., Ramsköld, L. & Zhou, G.-Q. Science 264, 1304−1308 (1994). | ISI |
  17. Shu, D., Geyer, G., Chen, L. & Zhang, X.-L. Beringeria (special issue) 2, 203−241 (1995).
  18. Conway Morris, S. Trans. R. Soc. Edinb. Earth Sci. 80, 271−283 (1989).
  19. Briggs, D. E. G. & Kear, A. J. Lethaia 26, 275−287 (1994).
  20. Butterfield, N. J. Lethaia 29, 109−112 (1996).
  21. Conklin, E. G. J. Morph. 54, 69−151 (1932).
  22. Peterson, K. J. Lethaia 28, 25−38 (1995). | ISI |
  23. Shu, D.-G., Zhang, X.-L. & Chen, L. Nature 380, 428−430 (1996). | Article | ISI | ChemPort |
  24. Chen, J.-Y., Dzik, J., Edgecombe, G. D., Ramsköld, L. & Zhou, G.-Q. Nature 377, 720−722 (1995). | Article | ISI | ChemPort |
  25. Dzik, J. Acta Palaeont. Pol. 40, 341−360 (1995).
  26. Gould, S. J. Nature 377, 681−682 (1995). | Article | ChemPort |
  27. Zhuravlev, A. Yu. Beringeria (special issue) 2, 147−160 (1995).
  28. Sansom, I. J., Smith, M. P., Armstrong, H. A. & Smith, M. M. Science 256, 1308−1311 (1992). | PubMed | ChemPort |
  29. Gabbott, S. E., Aldridge, R. J. & Theron, J. N. Nature 374, 800−803 (1995). | Article | ISI | ChemPort |
  30. Szaniawski, H. & Bengtson, S. J. Paleont. 67, 640−654 (1993).



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