Khairkhaniidae is an extinct family of Paleozoic fossil

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

s of uncertain position. They are thought to belong to either the

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

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

. They possess planispiral coiled shells with a columnar microstructure.

2005 taxonomy

The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classification and nomenclator of gastropod families''. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. . ISSN 0076-2997. 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278 categorizes Khairkhaniidae within the Paleozoic molluscs of uncertain systematic position. This family is unassigned to superfamily. This family has no subfamilies.

2006–2007 taxonomy

According to the P. Yu. Parkhaev, the Khairkhaniidae is the only family in the order Khairkhaniifomes within the subclass Divasibranchia. * 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 ...

** Subclass Divasibranchia Minichev & Starobogatov, 1975 *** Order Khairkhaniifomes Parkhaev, 2001 **** Family Khairkhaniidae Missarzhevsky, 1989

Genera

Genera in the family Khairkhaniidae include: * '' Khairkhania'' Missarzhevsky, 1981 - type genus of the family Khairkhaniidae ** '' Khairkhania rotata'' Missarzhevsky, 1981 *

Barskovia ''Barskovia'' is a torted conical shell known from earliest Cambrian small skeletal fossils, interpreted as a helcionelloid. References {{Taxonbar, from=Q21351640 Helcionelloida ...

References

Helcionelloida {{paleo-mollusc-stub