Aculifera

Aculifera is a proposed clade of molluscs incorporating those groups that have no conch or shell, that is, the Polyplacophora, Caudofoveata (=Chaetodermomorpha) and Solenogastres (=Neomeniomorpha).[1] It is sister to the Conchifera.

Aculifera Temporal range: Cambrian Stage 4–Holocene PreꞒ Ꞓ O S D C P T J K Pg N
A polyplacophoran (chiton)
The aplacophoran Epimenia
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Clade:	Aculifera Hatschek, 1891
Classes
†Mattheviidae Polyplacophora Aplacophora

The oldest known aculiferan is Qaleruaqia, which was found in the Aftenstjernesø Formation in Greenland, which dates back to the Cambrian Stage 4.[2]

References

1. Sigwart, J. D.; Sutton, M. D. (Oct 2007). "Deep molluscan phylogeny: synthesis of palaeontological and neontological data". Proceedings of the Royal Society B: Biological Sciences. 274 (1624): 2413–2419. doi:10.1098/rspb.2007.0701. PMC 2274978. PMID 17652065. For a summary, see "The Mollusca". University of California Museum of Paleontology. Retrieved 2 October 2008.
2. John S. Peel (2020). "The oldest palaeoloricate mollusc (Cambrian Series 2, Stage 4; North Greenland) and its bearing on aculiferan evolution". Bulletin of Geosciences. 95 (2): 127–144. doi:10.3140/bull.geosci.1779.