Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2006 May 16;103(20):7723-8. Epub 2006 May 4.

Evidence for a clade composed of molluscs with serially repeated structures: monoplacophorans are related to chitons.

Author information

  • 1Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, 16 Divinity Avenue, BioLabs 1119, Cambridge, MA 02138, USA. ggiribet@oeb.harvard.edu

Abstract

Monoplacophorans are among the rarest members of the phylum Mollusca. Previously only known from fossils since the Cambrian, the first living monoplacophoran was discovered during the famous second Galathea deep-sea expedition. The anatomy of these molluscs shocked the zoological community for presenting serially repeated gills, nephridia, and eight sets of dorsoventral pedal retractor muscles. Seriality of organs in supposedly independent molluscan lineages, i.e., in chitons and the deep-sea living fossil monoplacophorans, was assumed to be a relic of ancestral molluscan segmentation and was commonly accepted to support a direct relationship with annelids. We were able to obtain one specimen of a monoplacophoran Antarctic deep-sea species for molecular study. The first molecular data on monoplacophorans, analyzed together with the largest data set of molluscs ever assembled, clearly illustrate that monoplacophorans and chitons form a clade. This "Serialia" concept may revolutionize molluscan systematics and may have important implications for metazoan evolution as it allows for new interpretations for primitive segmentation in molluscs.

PMID:
16675549
[PubMed - indexed for MEDLINE]
PMCID:
PMC1472512
Free PMC Article

Publication Types, MeSH Terms, Secondary Source ID

Publication Types

MeSH Terms

Secondary Source ID

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk