As of July 2016, the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...

(IUCN) listed 987 critically endangered

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

species, including 206 which are tagged as possibly extinct. Of all evaluated invertebrate species, 5.5% are listed as critically endangered. The IUCN also lists 14 invertebrate subspecies as critically endangered. No subpopulations of invertebrates have been evaluated by the IUCN. Additionally 5278 invertebrate species (29% of those evaluated) are listed as data deficient, meaning there is insufficient information for a full assessment of conservation status. As these species typically have small distributions and/or populations, they are intrinsically likely to be threatened, according to the IUCN. While the category data deficient indicates that no assessment of extinction risk has been made for the taxa, the IUCN notes that it may be appropriate to give them "the same degree of attention as threatened taxa, at least until their status can be assessed". This is a complete list of critically endangered invertebrate species and subspecies as evaluated by the IUCN. Species considered possibly extinct by the IUCN are marked as such.

Nemertea Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species. Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many h ...
species

*'' Prosadenoporus agricola'' (possibly extinct)

Annelids The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecolog ...

*'' Mesonerilla prospera''

Onychophora Onychophora (from grc, ονυχής, , "claws"; and , , "to carry"), commonly known as velvet worms (due to their velvety texture and somewhat wormlike appearance) or more ambiguously as peripatus (after the first described genus, '' Peripatus ...

Molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...

There are 581 mollusc species and 11 mollusc subspecies assessed as critically endangered.

Gastropods The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. The ...

There are 511 gastropod species and six gastropod subspecies assessed as critically endangered.

Stylommatophora

Stylommatophora includes the majority of land snails and slugs. There are 233 species and five subspecies in the order Stylommatophora assessed as critically endangered.

= Amastrids

= Partulids

= Achatinellids

= Endodontids

= Species Subspecies

= Charopids

= Helicarionids

= Orthalicids

= Rhytidids

= Streptaxids

= Lauriids

= Helicids

= Hygromiids

= Enids

=Other Stylommatophora species

Littorinimorpha Littorinimorpha is a large order of snails, gastropods, consisting primarily of sea snails (marine species), but also including some freshwater snails ( aquatic species) and land snails ( terrestrial species).Bouchet P. & Rocroi J.-P. (Ed.); Frý ...

There are 181 species in the order Littorinimorpha assessed as critically endangered.

= Hydrobiids

= Cochliopids

= Bithyniids

= Moitessieriids

= *'' Henrigirardia wienini'' (possibly extinct) *'' Spiralix corsica'' (possibly extinct)

= Assimineids

= Pomatiopsids

Sorbeoconcha Sorbeoconcha is a taxonomic clade of snails, i.e. gastropods, mainly marine species with gills and opercula, within the clade Caenogastropoda. The taxon Sorbeoconcha was named by Winston Ponder and David R. Lindberg in 1997. Taxonomy 1 ...

Architaenioglossa

There are 48 species in the order Architaenioglossa assessed as critically endangered.

= Cyclophorids

= Diplommatinids

= Viviparids

=Other Architaenioglossa species

Cycloneritimorpha

Hygrophila

Species Subspecies *'' Bulinus tropicus torensis''

Neogastropoda

Other gastropod species

Bivalvia Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biva ...

There are 69 species and five subspecies in the class Bivalvia assessed as critically endangered.

Unionida Unionida is a monophyletic order of freshwater mussels, aquatic bivalve molluscs.Bieler R., Carter J.G. & Coan E.V. (2010). ''Classification of Bivalve families''. pp. 113–133, in: Bouchet P. & Rocroi J.-P. (2010), ''Nomenclator of Bivalve Fa ...

There are 66 species and five subspecies in the order Unionoida assessed as critically endangered.

= Margaritiferids

= Species Subspecies *'' Margaritifera margaritifera durrovensis''

= Etheriids

= *'' Acostaea rivolii''

= Unionids

= Species Subspecies

= Hyriids

= * Glenelg freshwater mussel (''Hyridella glenelgensis'')

Venerida Venerida (formerly Veneroida) is an order of mostly saltwater but also some freshwater bivalve molluscs. This order includes many familiar groups such as many clams that are valued for food and a number of freshwater bivalves. Since the 2000s, t ...

Cephalopods

*'' Opisthoteuthis chathamensis''

Cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that ...

Arthropods

There are 394 arthropod species and three arthropod subspecies assessed as critically endangered.

Centipedes Centipedes (from New Latin , "hundred", and Latin , "foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', lip, and New Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, an a ...

Seed shrimps

*'' Kapcypridopsis barnardi'' *'' Spelaeoecia bermudensis''

Arachnids

There are 47 arachnid species assessed as critically endangered.

Harvestmen The Opiliones (formerly Phalangida) are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. , over 6,650 species of harvestmen have been discovered worldwide, although the total number of extan ...

Spiders Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species di ...

Other arachnid species

Branchiopoda Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca (or Cladocera), Notostraca and the Devonian ''Lepidocaris''. They are mostly small, freshwater animals that feed on plankton and detritus. Description ...

Millipedes Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a resu ...

Entognatha The Entognatha are a class of wingless and ametabolous arthropods, which, together with the insects, makes up the subphylum Hexapoda. Their mouthparts are entognathous, meaning that they are retracted within the head, unlike the insects. Entog ...

* ''Ceratophysella'' sp. nov. 'HC' (possibly extinct) *'' Delamarephorura tami'' (possibly extinct)

Maxillopoda Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

Malacostracans

Malacostraca includes crabs, lobsters, crayfish, shrimp, krill, woodlice, and many others. There are 125 malacostracan species and one malacostracan subspecies assessed as critically endangered.

Mysida

*'' Bermudamysis speluncola'' * Sterrer's cave mysid (''Platyops sterreri'')

Mictaceans

*''

Mictocaris halope ''Mictocaris halope'' is the only species of cave crustacean in the monotypic genus ''Mictocaris''. It is placed in its own family, Mictocarididae, and is sometimes considered the only member of the order Mictacea. ''Mictocaris'' is endemic to ...

Isopods Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and ...

Amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far describ ...

Decapods The Decapoda or decapods (literally "ten-footed") are an order (biology), order of crustaceans within the class Malacostraca, including many familiar groups, such as crabs, lobsters, crayfish, Caridea, shrimp and Dendrobranchiata, prawns. Most ...

There are 106 decapod species and one decapod subspecies assessed as critically endangered.

= Parastacids

= Gecarcinucids

= Atyids

= Cambarids

= Species Subspecies *'' Procambarus rogersi expletus''

= Palaemonids

=Other decapod species

Insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

There are 195 insect species and two insect subspecies assessed as critically endangered.

Blattodea Blattodea is an order of insects that contains cockroaches and termites. Formerly, termites were considered a separate order, Isoptera, but genetic and molecular evidence suggests they evolved from within the cockroach lineage, cladistically ...

Orthoptera

There are 72 species in the order Orthoptera assessed as critically endangered.

= Euschmidtiids

=
Crickets Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...

= Acridids

= Tettigoniids

Odonata Odonata is an order of flying insects that includes the dragonflies and damselflies. Members of the group first appeared during the Triassic, though members of their total group, Odonatoptera, first appeared in Late Carboniferous. The two com ...

Species Subspecies *'' Chlorogomphus brunneus keramensis'' * Delphi cordulegaster (''Cordulegaster helladica kastalia'')

Other insect species

References

* *Invertebrates Critically endangered invertebrates {{bots, deny=BG19bot,Yobot

Nemertea Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species. Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many h ... species