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Proc Biol Sci. 2004 August 22; 271(1549): 1671–1676.
PMCID: PMC1691784

Early Cambrian sipunculan worms from southwest China.


We report the discovery of sipunculan worms from the Lower Cambrian Maotianshan Shale, near Kunming (southwest China). Their sipunculan identity is evidenced by the general morphology of the animals (sausage-shaped body with a slender retractable introvert and a wider trunk) and by other features, both external (e.g. perioral crown of tentacles, and hooks, papillae and wrinkle rings on the body surface) and internal (U-shaped gut, and the anus opening near the introvert-trunk junction). The three fossil forms (Archaeogolfingia caudata gen. et sp. nov., Cambrosipunculus tentaculatus gen. et sp. nov. and Cambrosipunculus sp.) have striking similarities to modern sipunculans, especially the Golfingiidae to which their evolutionary relationships are discussed. This study suggests that most typical features of extant sipunculans have undergone only limited changes since the Early Cambrian, thus indicating a possible evolutionary stasis over the past 520 Myr.

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Selected References

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  • Boore Jeffrey L, Staton Joseph L. The mitochondrial genome of the Sipunculid Phascolopsis gouldii supports its association with Annelida rather than Mollusca. Mol Biol Evol. 2002 Feb;19(2):127–137. [PubMed]
  • Chen Jun-Yuan, Huang Di-Ying. A possible Lower Cambrian chaetognath (arrow worm). Science. 2002 Oct 4;298(5591):187–187. [PubMed]
  • Maxmen Amy B, King Burnett F, Cutler Edward B, Giribet Gonzalo. Evolutionary relationships within the protostome phylum Sipuncula: a molecular analysis of ribosomal genes and histone H3 sequence data. Mol Phylogenet Evol. 2003 Jun;27(3):489–503. [PubMed]

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