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Gastropod Main
Glossary
References
Links
Hooper Main |
Fossil Record 2
All molluscs are thought to have evolved from a single archimollusc ancestor alive in the early Cambrian. Although fossils of this hypothetical ancestor have never been found, it's internal structure may be deduced from retrograding the morphologies of each of the mollusc classes back to commonality. Fig. 14 shows what this archimollusc may have looked like internally (centre diagram) before radiative evolution.
Figure 15: Radiative evolution of the Molluscs. All the mollusc classes are believed to have evolved from an ancestral mollusc (centre). Note the similarity in shape of this archimollusc with some primitive gastropods, and the limpets.
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