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Index to Creationist Claims,  edited by Mark Isaak,    Copyright © 2006
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Claim CC211:

No fossils have been found transitional between invertebrates and vertebrates.

Source:

Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master Books, p. 82

Response:

  1. There are Cambrian fossils transitional between vertebrate and invertebrate:
    1. Pikaia, an early invertebrate chordate. It was at first interpreted as a segmented worm until a reanalysis showed it had a notochord.
    2. Yunnanozoon, an early chordate.
    3. Haikouella, a chordate similar to Yunnanozoon, but with additional traits, such as a heart and a relatively larger brain (Chen et al. 1999).
    4. Conodont animals had bony teeth, but the rest of their body was soft. They also had a notochord (Briggs et al. 1983; Sansom et al. 1992).
    5. Cathaymyrus diadexus, the oldest known chordate (535 million years old; Shu et al. 1996).
    6. Myllokunmingia and Haikouichthys, two early vertebrates that still lack a clear head and bony skeletons and teeth. They differ from earlier invertebrate chordates in having a zigzag arrangement of segmented muscles, and their gill arrangement is more complex than a simple slit (Monastersky 1999).

  2. There are living invertebrate chordates (Branchiostoma [Amphioxus], urochordates [tunicates]) and living basal near-vertebrates (hagfish, lampreys) that show plausible intermediate forms.

Links:

Monastersky, Richard, 1999. Waking up to the dawn of vertebrates. Science News 156: 292. http://www.sciencenews.org/sn_arc99/11_6_99/fob1.htm

References:

  1. Briggs, D. E. G., E. N. K. Clarkson and R. J. Aldridge, 1983. The conodont animal. Lethaia 16: 1-14.
  2. Chen, J.-Y., D.-Y. Huang and C.-W. Li, 1999. An early Cambrian craniate-like chordate. Nature 402: 518-522. http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v402/n6761/full/402518a0_r.html
  3. Monastersky, R., 1999. (see above).
  4. Sansom, I. J., M. P. Smith, H. A. Armstrong and M. M. Smith, 1992. Presence of the earliest vertebrate hard tissues in conodonts. Science 256: 1308-1311.
  5. Shu, D.-G., S. Conway Morris and X.-L. Zhang, 1996. A Pikaia-like chordate from the Lower Cambrian of China. Nature 384: 157-158.

Further Reading:

Speer, B. R. 2000. Introduction to the Deuterostomia. http://www.ucmp.berkeley.edu/phyla/deuterostomia.html

Waggoner, Ben. 1996. Introduction to the Cephalochordata. http://www.ucmp.berkeley.edu/chordata/cephalo.html
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created 2003-7-5