Cyrtonellida is a group of "
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 ...
", representing either a sister
taxon
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
to, or a
polyphyletic assemblage
A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as homoplasies, which ar ...
including, the
Trybliida.
Subtaxa
*
Carcassonnellidae
*
Cyrtolitidae
Cyrtolitidae is an extinct family of monoplacophorans in the order Cyrtonellida.
Genera
* '' Cloudia''
* '' Cyclocyrtonella''
* '' Cyrtolites''
* '' Cyrtonellopsis''
* '' Kolihadiscus''
* '' Neocyrtolites''
* '' Paracyrtolites''
* '' Quasisin ...
*
Cyrtonelloidea
*
Pollicinidae
; Genera
* ''
Aremellia''
* ''
Hamusella''
* ''
Tetamocornu''
* ''
Yangtzeconus''
* ''
Yochelsonia''
References
External links
*
Prehistoric monoplacophorans
Mollusc orders
{{Paleo-mollusc-stub