class of molluscs
The Helcionelloida are an extinct class of fossil molluscs.
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They are among the earliest animals with mineralised shells. They are also the oldest known molluscs wth a shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991.
The latest word on this group is the classification of Parkhaev, who splits it into three subclasses.
- ↑ 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. The early evolution of metazoa and the significance of problematic taxa. Cambridge University Press, pp. 157–177. ISBN 978-0-521-40242-2
- ↑ P. Yu. Parkhaev (2006) "Adaptive radiation of the Cambrian helcionelloid mollusks (Gastropoda, Archaeobranchia). Archived 2015-06-10 at the Wayback Machine" In: S.V. Rozhnov (ed.) "Evolution of the biosphere and biodiversity. Towards the 70th anniversary of A. Y. Rozanov". 2006. Moscow, pp. 282-296.
- ↑ P. Yu. Parkhaev (2007). "The Cambrian 'basement' of gastropod evolution". Geological Society, London, Special Publications. 286 (1): 415–421. Bibcode:2007GSLSP.286..415P. doi:10.1144/SP286.31. S2CID 130979274.