Yochelcionelloidea is an extinct superfamily of paleozoic

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s of uncertain position (

Gastropoda Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

Monoplacophora Shell of Monoplacophora Monoplacophora , meaning "bearing one plate", is a polyphyletic class of molluscs with a cap-like shell, inhabiting deep sea environments. Extant representatives were not recognized as such until 1952; previously they wer ...

). The earliest yochelcionellids are known from the Middle Tommotian, but they are most diverse from the Botomian through the early Middle Cambrian.Pavel Yu. Parkhaev (2008). "
The Early Cambrian Radiation of Mollusca.
'" In: "''Phylogeny and evolution of the Mollusca.''" Edited by: Ponder WF, Lindberg DR. Berkeley: University of California Press: 33-69.

2005 taxonomy

The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005: Yochelcionelloidea * †

Yochelcionellidae ''Yochelcionella'' is an extinct genus of basal molluscs which lived during the Tommotian epoch, the first epoch of the Cambrian period. This genus is often reconstructed to resemble snails. ''Yochelcionella'' is the type genus of the family Y ...

* †

Stenothecidae Stenothecidae is an extinct family of fossil univalved Cambrian molluscs which may be either gastropods or monoplacophorans. The name of this taxon should not be confused with that of the class Stenothecoida, a group of problematic Cambrian i ...

* †

Trenellidae ''Trenella'' is the sole genus in the Trenellidae, an extinct family of paleozoic Yochelcionellids. 2005 taxonomy The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Vald ...

2006-2007 taxonomy

According to the opinion of P. Yu. Parkhaev is in the class

Helcionelloida 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 ere ...

, subclass Archaeobranchia Parkhaev, 2001, Order Helcionelliformes Golikov & Starobogatov, 1975:P. Yu. Parkhaev (2007) ''"The Cambrian ‘basement’ of gastropod evolution"''. In: Vickers-Rich, P. & Komarower, P. (eds.) ''"The Rise and Fall of the Ediacaran Biota"'', Special publications, 286, London: Geological Society, pp. 415–421. :*Superfamily Yochelcionelloidea Runnegar & Jell, 1976 ::*Family

Parkhaev, 2001 ::*Family

Runnegar & Jell, 1976 ::*Family

Runnegar & Jell, 1980 :::*Subfamily Stenothecinae Runnegar & Jell, 1980 :::*Subfamily Watsonellinae Parkhaev, 2001

References

{{Taxonbar, from=Q8054245 Helcionelloida