Conchifera is a
subphylum of the phylum
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 ...
a, containing five extant
classes:
Monoplacophora,
Cephalopoda,
Gastropoda,
Bivalvia, and
Scaphopoda.
Conchiferans can bear a single
shell
Shell may refer to:
Architecture and design
* Shell (structure), a thin structure
** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses
Science Biology
* Seashell, a hard outer layer of a marine ani ...
as in
snails and
ammonites, a single pair of shells as in
clams, or lack a shell as in
slugs and
squid
A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...
. The other subphylum is
Aculifera, the members of which are shellless or have a row of several plates.
Non-monoplacophoran conchiferans emerged within the once-widespread Monoplacophora. The only descendant which retains its ancestral shape is the
Tryblidiida.
The monophyly of Conchifera is supported by molecular phylogenetic analysis.
The relationships among the members of Conchifera are disputed.
A grouping of Scaphopoda and Bivalvia, named
Diasoma, has been proposed,
but other studies find scaphopods to be more closely related to cephalopods
or gastropods.
Conchifera originated in the early
Cambrian period.
Classes
Classes within the Conchifera include:
*
Monoplacophora
*
Bivalvia
*
Gastropoda
*
Scaphopoda
*
Cephalopoda
*
Archinacelloidea†
*
Rostroconchia†
*
Helcionelloida†
See also
*
Evolution of Mollusca
References
External links
BioLib info
{{Authority control
Mollusc taxonomy
Animal subphyla
Prehistoric mollusc taxonomy