Synallactida is a rankless
clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
of
sea cucumber
Sea cucumbers are echinoderms from the class (biology), class Holothuroidea ( ). They are benthic marine animals found on the sea floor worldwide, and the number of known holothuroid species worldwide is about 1,786, with the greatest number be ...
s, but is referred to as an
order
Order, ORDER or Orders may refer to:
* A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
...
.
Taxa within Synallactida were previously classified in an order called Aspidochirotida, which was determined to be
polyphyletic
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 Homoplasy, homoplasies ...
in 2017.
List of families
Synallactida includes over 130
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
in three extant
families
Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...
and two extinct genera:
*
Deimatidae Théel, 1882 – 3 genera
*
Stichopodidae
The Stichopodidae are a Family (biology), family of sea cucumbers, part of the order Synallactida.
Description
Members of this family are mostly large or medium-sized sea cucumber, holothuroids with an angular body shape (almost forming a squar ...
Haeckel, 1896 – 9 genera
*
Synallactidae Ludwig, 1894 – 12 genera
* Genus †''
Collbatothuria''
Smith & Gallemí, 1991
* Genus †''
Tribrachiodemas''
Reich, 2010
Image:Parastichopus californicus.jpg, '' Apostichopus californicus''
Image:Australostichopus mollis P1222859.JPG, '' Australostichopus mollis''
Image:Isostichopus badionotus.jpg, '' Isostichopus badionotus''
Image:Stichopus chloronotus Réunion.jpg, '' Stichopus chloronotus''
Image:Stichopus sp.png, '' Isostichopus fuscus''
Image:Thelenota anax.jpg, '' Thelenota anax''
References
{{Holothuroidea-stub