E-resources
Peer reviewed
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Shu, D-G; Luo, H-L; Conway Morris, S; Zhang, X-L; Hu, S-X; Chen, L; Han, J; Zhu, M; Li, Y; Chen, L-Z
Nature (London), 11/1999, Volume: 402, Issue: 6757Journal Article
The first fossil chordates are found in deposits from the Cambrian period (545-490 million years ago), but their earliest record is exceptionally sporadic and is often controversial. Accordingly, it has been difficult to construct a coherent phylogenetic synthesis for the basal chordates. Until now, the available soft-bodied remains have consisted almost entirely of cephalochordate-like animals from Burgess Shale-type faunas.
