Parachela is an order of

tardigrade Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them . In 1776, th ...

s in the class

Eutardigrada Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendages. Primarily freshwater bound, some species have secondarily gained the ability to live in marine environments ('' Halobiotus''). By cryptobiosis many species are able ...

. Members of this order have existed for at least 72 million years, up to the present. The oldest known species are '' Beorn leggi'' and ''

Aerobius dactylus ''Aerobius'' is a genus of extinct tardigrades ("water bears") of the superfamily Hypsibioidea. The genus contains a Monotypic taxon, single species, ''A. dactylus'', known from a single individual preserved in amber. The ''Aerobius'' holotype i ...

''.

Superfamilies and families

The order includes the following superfamilies and families: * Eohypsiboiidea **

Eohypsibiidae ''Eohypsibiidae'' is a family of water bear or moss piglet, tardigrades in the class Eutardigrada Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendages. Primarily freshwater bound, some species have secondarily gained ...

* Hypsibioidea ** Calohypsibiidae **

Hypsibiidae The Hypsibiidae are a family of water bears or moss piglets, tardigrades in the class Eutardigrada. Subfamilies and genera * Subfamily Diphasconinae ** '' Diphascon'' ** '' Hebesuncus'' ** '' Paradiphascon'' * Subfamily Hypsibiinae ** ''Acutu ...

Microhypsibiidae Microhypsibiidae is a family of tardigrades in the class Eutardigrada Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendages. Primarily freshwater bound, some species have secondarily gained the ability to live in mari ...

** Ramazzottiidae * Isohypsibioidea ** Hexapodibiidae ** Isohypsibiidae * Macrobiotoidea **

Beornidae ''Beorn'' is an extinct genus of tardigrade and the first known fossil tardigrade, discocered in Late Cretaceous amber from Manitoba, Canada. The genus contains a single species, ''B. leggi'', and it was originally classified as the only member ...

Macrobiotidae Macrobiotidae is a family of tardigrades. Phylogeny External phylogeny According to a 2018 report using multiple morphological and molecular studies, the Macrobiotoidea are sister to the Hypsibioidea; both are eutardigrades. The genera '' ...

** Murrayidae **

Necopinatidae ''Necopinatidae'' is a family of water bears or moss piglets, tardigrades in the class Eutardigrada Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendages. Primarily freshwater bound, some species have secondarily gain ...

Richtersiidae Richtersiidae is a family of tardigrade Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Go ...

References

External links

* * Ecdysozoa orders Polyextremophiles {{Tardigrade-stub