Back Helcionelloida Bulgarian Helcionel·lòides Catalan Helcionelliden German Helcionelloida Spanish Helcionelloida Italian ヘルシオネラ綱 Japanese Helcionelloida Polish Helcionelloida Portuguese Helcionelloida Russian Helcionelloida SIMPLE
| Helcionelloida Temporal range:
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|---|---|
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| Latouchella costata | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Subphylum: | Conchifera |
| Class: | †Helcionelloida Peel, 1991 |
| Orders | |
and see text | |
Helcionelloida is an extinct group of ancient molluscs (phylum Mollusca). These are the oldest known conchiferan molluscs, that is, they had a mineralised shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991.[1]
- ^ Peel, J. S. (1991). "Functional Morphology of the Class Helcionelloida Nov., and the Early Evolution of the Mollusca". In Simonetta, A. M.; Conway Morris, S (eds.). The Early Evolution of Metazoa and the Significance of Problematic Taxa. Cambridge University Press. pp. 157–177. ISBN 978-0-521-40242-2.