Khairkhaniidae is an extinct family

Family

In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...

 of Paleozoic

Paleozoic

The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...

 fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 molluscs of uncertain position. They are thought to belong to either the Gastropoda

Gastropoda

The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...

 or Monoplacophora

Monoplacophora

Monoplacophora, meaning "bearing one plate", is a polyphyletic class of mollusks with a cap-like shell, living on the bottom of deep sea. Extant representatives were unknown until 1952; previously they were known only from the fossil record.- Definition :...

.
They possess planispiral coiled shells with a columnar microstructure.

2005 taxonomy

The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005

Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)

The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...

 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
  Helcionelloida is the name given to an extinct group of ancient molluscs . 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.-Anatomy:These animals were...
  
  
  • 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
  Type genus
  In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
  
   of the family Khairkhaniidae
  • Khairkhania rotata Missarzhevsky, 1981