List of bilateral animal orders contains the

Bilateria The Bilateria or bilaterians are animals with bilateral symmetry as an embryo, i.e. having a left and a right side that are mirror images of each other. This also means they have a head and a tail (anterior-posterior axis) as well as a belly and ...

of the animal subkingdom

Eumetazoa Eumetazoa (), also known as diploblasts, Epitheliozoa, or Histozoa, are a proposed basal animal clade as a sister group of the Porifera (sponges). The basal eumetazoan clades are the Ctenophora and the ParaHoxozoa. Placozoa is now also seen as a ...

, divided into four superphyla,

Deuterostomia Deuterostomia (; in Greek) are animals typically characterized by their anus forming before their mouth during embryonic development. The group's sister clade is Protostomia, animals whose digestive tract development is more varied. Some ex ...

, and the three

Protostome Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's memb ...

superphyla,

Ecdysozoa Ecdysozoa () is a group of protostome animals, including Arthropoda (insects, chelicerata, crustaceans, and myriapods), Nematoda, and several smaller phyla. They were first defined by Aguinaldo ''et al.'' in 1997, based mainly on phylogenetic tr ...

, and the two

Spiralia The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. The term ''Spiralia'' is applied to those phyla that exhibit canonical spiral cleavage, a ...

superphyla,

Platyzoa The paraphyletic "Platyzoa" are a group of protostome unsegmented animals proposed by Thomas Cavalier-Smith in 1998. Cavalier-Smith included in Platyzoa the phylum Platyhelminthes (or flatworms), and a new phylum, the Acanthognatha, into whic ...

and

Lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...

Phylum
Xenacoelomorpha Xenacoelomorpha is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2011 and suggested based on morphological synapomorphies (physical app ...

; Subphylum Xenoturbelida * Class '' incertae sedis'' (Family Xenoturbellidae) ; Subphylum

Acoelomorpha Acoelomorpha is a subphylum of very simple and small soft-bodied animals with planula-like features which live in marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, suc ...

* Class Acoela ** Order ''incertae sedis'' (16 families) * Class

Nemertodermatida Nemertodermatida is a class of Acoelomorpha, comprising 18 species of millimetre-sized turbellariform, mostly interstitial worms. Taxonomy The order ''Nemertodermatida'' contains two families with 6 genera. The high level of cryptic diversity ...

** Order ''incertae sedis'' (2 families)

Nephrozoa (unranked)

Infrakingdom
Deuterostomia Deuterostomia (; in Greek) are animals typically characterized by their anus forming before their mouth during embryonic development. The group's sister clade is Protostomia, animals whose digestive tract development is more varied. Some ex ...

Phylum
Chordata A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fiv ...

Ambulacraria Ambulacraria , or Coelomopora , is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member of this group is called an ambulacrarian. Phylogenetic analysis suggests the echinoderms and hemichordates separated around 533 ...

Phylum Hemichordata

; Class Enteropneusta (

Acorn worms The acorn worms or Enteropneusta are a hemichordate class of invertebrates consisting of one order of the same name. The closest non-hemichordate relatives of the Enteropneusta are the echinoderms. There are 111 known species of acorn worm in the ...

) * Order Enteropneusta ; Class Graptolithina † * Order

Camaroidea Cysticamaridae is an extinct family of graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from t ...

† * Order

Crustoidea Wimanicrustidae is an extinct family of graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding Filter feeders are a sub-group of suspension feedin ...

† * Order Dendroidea † * Order

Dithecoidea Dithecodendridae is an extinct family of graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding Filter feeders are a sub-group of suspension feedi ...

† * Order Graptoloidea † * Order Stolonoidea † * Order

Tuboidea Cyclograptidae is an extinct family of graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding Filter feeders are a sub-group of suspension feeding ...

† ; Class

Planctosphaeroidea ''Planctosphaera pelagica'' is a hemichordate and the only known representative of the class Planctosphaeroidea. The species is known only by its free swimming larvae. The larvae are tornaria larvae similar to those of the closely related Entero ...

No order, one genus, one species ''Planctosphaera pelagica'' ; Class

Pterobranchia Pterobranchia is a class of small worm-shaped animals. They belong to the Hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. The ...

* Order

Cephalodiscida Cephalodiscida is one of two orders in the class Pterobranchia, which are small, worm-shaped animals. Members belong to the hemichordates. Species in this order are sessile, living in clear water and secrete tubes on the ocean floor. Taxonomy Th ...

* Order

Rhabdopleurida Rhabdopleurida is one of three orders in the class Pterobranchia, which are small, worm-shaped animals, are the only surviving graptolites. Members belong to the hemichordates. Species in this order are sessile, colonial, connected with a stolon ...

Phylum
Echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea ...
ata

Infrakingdom
Protostomia Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's mem ...

Superphylum
Ecdysozoa Ecdysozoa () is a group of protostome animals, including Arthropoda (insects, chelicerata, crustaceans, and myriapods), Nematoda, and several smaller phyla. They were first defined by Aguinaldo ''et al.'' in 1997, based mainly on phylogenetic tr ...

Cycloneuralia Cycloneuralia is a clade of ecdysozoan animals including the Scalidophora (Kinorhynchans, Loriciferans, Priapulids) and the Nematoida (nematodes, Nematomorphs). It may be paraphyletic, or may be a sister group to Panarthropoda. Or perhaps Pana ...
(unranked)

= Scalidophora (unranked)

Phylum

Kinorhyncha Kinorhyncha ( grc, κινέω, kīnéō, I move, ' "snout") is a phylum of small marine invertebrates that are widespread in mud or sand at all depths as part of the meiobenthos. They are also called mud dragons. Modern species are or less, ...

No class, 2 orders, called mud dragons, very common in mud or sand * Order

Cyclorhagida Cyclorhagida is a class of kinorhynchs, which are small marine invertebrates. Orders and families * Order Echinorhagata Sørensen et al., 2015 ** Echinoderidae Zelinka, 1894Zelinka, C. (1894). Über die Organisation von Echinoderes. ''Verhan ...

* Order Homalorhagida

Phylum

Loricifera Loricifera (from Latin, '' lorica'', corselet (armour) + ''ferre'', to bear) is a phylum of very small to microscopic marine cycloneuralian sediment-dwelling animals that had been determined to be 37 described species, in 9 genera, bu ...

No class, one order Nanaloricida

Phylum

Priapulida Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertility ...

; Class Priapulimorpha * Order Priapulimorphida ** Family

Priapulidae Priapulidae is the canonical family of priapulid Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name ...

** Family

Tubiluchidae Tubiluchidae is one of the two families of priapulimorphidan priapulid Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented ...

; Class

Halicryptomorpha ''Halicryptus'' is the sole genus of its class of priapulid worms, and grows to great size. It has an important effect on the structure of soft-sediment communities. This genus contains the following species: * ''Halicryptus higginsi'' * ''Ha ...

* Order Halicryptomorphida ; Class Seticoronaria * Order Seticoronarida *** Genus Maccabeus

=
Nematoida Nematoida is a grouping of animals, including the roundworms The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known ...
(unranked)

Phylum Nematoda

Phylum Nematomorpha

; Class Gordioidea ; Class

Nectonematoida ''Nectonema'' is a genus of marine Nematomorpha, horsehair worms first described by Addison Emery Verrill, Addison E. Verrill in 1879. It is the only genus in the family Nectonematidae described by Henry Baldwin Ward, Henry B. Ward in 1892, in th ...

Panarthropoda Panarthropoda is a proposed animal clade containing the extant phyla Arthropoda, Tardigrada (water bears) and Onychophora (velvet worms). Panarthropods also include extinct marine legged worms known as lobopodians ("Lobopodia"), a paraphyletic g ...
(unranked)

= Phylum Lobopodia †

= ;Class Dinocaridida * Kerygmacheloidea **

Kerygmachela ''Kerygmachela kierkegaardi'' is a gilled lobopodian from the Cambrian Stage 3 aged Sirius Passet Lagerstätte in northern Greenland. Its anatomy strongly suggests that it, along with its relative ''Pambdelurion whittingtoni'', was a close relat ...

** Pambdulurion * Anomalocaromorpha **

Parapeytoia ''Parapeytoia'' was a prehistoric arthropod that lived over 530 million years ago (Cambrian Stage 3) in the Maotianshan shales of prehistoric China. It was interpreted as an anomalocaridid (radiodont) with legs, but later studies reveal it was ...

** Anomalocaria *** Opabiniidae ****

Opabinia ''Opabinia regalis'' is an extinct, stem group arthropod found in the Middle Cambrian Burgess Shale Lagerstätte (505 million years ago) of British Columbia. ''Opabinia'' was a soft-bodied animal, measuring up to 7 cm in body length, and it ...

**** Myoscolex ***

Anomalocarida Radiodonta is an extinct Order (biology), order of stem-group arthropods that was successful worldwide during the Cambrian period. They may be referred to as radiodonts, radiodontans, radiodontids, anomalocarids, or anomalocaridids, although the ...

**** Pennsylvaniocaris **** Piococaris **** Sarocaris ****

Paranomalocaris ''Paranomalocaris'' is a genus of primitive radiodont recovered from Wulongqing Formation, eastern Yunnan. It contains two species, ''Paranomalocaris multisegmentalis'' and ''P. simplex''. It is only known from its frontal appendage (now known t ...

****

Anomalocarididae Anomalocarididae (occasionally mis-spelt Anomalocaridae) is an extinct family of Cambrian radiodonts, a group of stem-group arthropods. Around 1990s and early 2010s, Anomalocarididae included all radiodont species, hence the previous equivalen ...

; Class Xenusia * Order Archonychophora **

Luolishaniidae The Luolishaniidae or Luolishaniida are a group of Cambrian and Ordovician lobopodians with anterior 5 or 6 pairs of setiferous lobopods. Most luolishaniids also have posterior lobopods each with a hooked claws, and thorn-shaped sclerites arran ...

***'' Luolishania'' ***''

Miraluolishania ''Miraluolishania'' is an extinct lobopodian known from Chengjiang County in China. It is remarkable for the possession of lensed pit-eyes. The only species, ''Miraluolishania haikouensis'', was described from the Maotianshan Shales at Haikou by ...

'' ** Paucipodiidae ***'' Paucipodia'' * Order Protonychophora ** Aysheaiidae ***''

Aysheaia ''Aysheaia'' is an extinct genus of soft-bodied lobopod, known from the middle Cambrian of North America, with an average body length of 1–6 cm. Anatomy ''Aysheaia'' has ten body segments, each of which has a pair of spiked, annulate le ...

'' ** Xenusiidae ***''

Xenusion ''Xenusion auerswaldae'' is an early lobopodian known from two specimens found in glacial erratics on the Baltic coast of Germany. They probably originated in the Kalmarsund Sandstone of Southern Sweden, which was deposited in the Lower Camb ...

'' ***'' Jianshanopodia'' ***''

Hadranax ''Hadranax augustus'' is a species of xenusiid lobopodian known from the lower Cambrian Sirius Passet ''Lagerstätte A Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary depos ...

'' ***''

Siberion ''Siberion'' is an extinct genus of lobopodian from the Sinsk biota of Russia. Its anatomy, including the proboscis-like organ projecting from the face and prominent grasping first pair of appendages, suggests that xenusians like this organism ma ...

'' * Order Archonychophora **

***'' Luolishania'' ***''

'' ** Paucipodiidae ***'' Paucipodia'' * Order Scleronychophora ** Eoconchariidae ***'' Microdictyon'' ***''

Quadratapora ''Quadratapora'' is a genus of lobopodian known only from its biomineralized dorsal plates, which somewhat resemble those of ''Microdictyon''. Its fossils date to the Tommotian Stage 2 of the Cambrian is the unnamed upper stage of the Terren ...

'' ***'' Fusuconcharium'' **

Hallucigeniidae Hallucigeniidae is a family of extinct worms belonging to the group Lobopodia that originated during the Cambrian explosion. It is based on the species ''Hallucigenia sparsa'', the fossil of which was discovered by Charles Doolittle Walcott in 1 ...

***'' Hallucigenia'' ** Cardiodictyidae ***'' Cardiodictyon'' * Order Paronychophora ** Onychodictyidae ***''

Onychodictyon ''Onychodictyon'' is a genus of extinct lobopodian known from the Lower Cambrian Chengjiang Maotianshan Shales in the Yunnan Province in China. It was characterized by a stout body covered by fleshy papillae and pairs of sclerotized plates with s ...

'' * Order unassigned **'' Orstenotubulus'' **''

Carbotubulus ''Carbotubulus'' is a genus of extinct worm belonging to the group Lobopodia and known from the Carboniferous Carbondale Formation of the Mazon Creek area in Illinois, US. A monotypic genus, it contains one species ''Carbotubulus waloszeki''. It w ...

'' **''

Mureropodia ''Mureropodia'' is an animal that existed in what is now the Valdemiedes Formation of Spain during the early Cambrian period. It was described by José Antonio Gámez Vintaned, Eladio Liñán and Andrey Yu. Zhuravlev in 2011, and the type and only ...

= Phylum Onychophora

= * Order

Euonychophora Euonychophora is an order of Onychophora representing all living onychophorans; the Peripatidae (including the fossil †'' Cretoperipatus'') and Peripatopsidae. Their feet possess a pair of claws and a pad, and are covered with pustules. All re ...

**Family

Peripatidae Peripatidae is a family of velvet worms. The oldest putative representatives of the family herald from Burmese amber dated to the mid-Cretaceous, around 100 Ma, with representatives from Dominican and Baltic amber attesting to a broader distribu ...

**Family

Peripatopsidae Peripatopsidae is one of the two living velvet worm families. Description The Peripatopsidae exhibit relatively many characteristics that are perceived as original or "primitive" with respect to the Peripatidae. The number of leg pairs in this f ...

*Order

Ontonychophora Ontonychophora is an extinct order of onychophoran consisting of organisms with simple lobopods that lack terminal feet. It includes all fossil onychophorans except †'' Cretoperipatus'', which is in the Euonychophora along with all remaining m ...

† **Family Helenodoridae † **Family Tertiapatoidea †

=
Tactopoda Tactopoda is a proposed clade of protostome animals that includes the phyla Tardigrada and Euarthropoda, supported by various morphological observations. The cladogram below shows the relationships implied by this hypothesis. The competing hyp ...
(unranked)

Phylum Tardigrada

; Class

Eutardigrada Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendices. Primarily freshwater bound, some species have secondarily gained the ability to live in marine environments (''Halobiotus''). By cryptobiosis many species are able t ...

* Order Apochela ** Family

Milnesiidae Milnesiidae is a family of tardigrades of the class Eutardigrada It is the sole family in the order Apochela. Genera The family consists of the following genera: * ''Bergtrollus'' Dastych, 2011 * ''Limmenius'' Horning, Schuster & Grigarick, 1 ...

* Order Parachela ** Family Beornidae ** Family

Calohypsibiidae Calohypsibiidae 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 Goeze ...

** Family

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 appendices. Primarily freshwater bound, some species have secondarily gained ...

** Family Hypsibiidae ** Family

Macrobiotidae Macrobiotidae is a family of tardigrade. , it consists of the following genera: * '' Biserovus'' * '' Calcarobiotus'' ** ''C.'' (''Calcarobiotus'') ** ''C.'' (''Discrepunguis'') * '' Famelobiotus'' * '' Insuetifurca'' * '' Macrobiotus'' * ...

** Family

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

** Family

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 appendices. Primarily freshwater bound, some species have secondarily gain ...

; Class

Heterotardigrada The class Heterotardigrada includes tardigrades (water bears) that have cephalic appendages and legs with four separate but similar digits or claws on each. 444 species have been described. Anatomy The anatomy of the reproductive system is an ...

* Order

Arthrotardigrada Arthrotardigrada are an order of tardigrades, first described by Marcus in 1927. Families Arthrotardigrada consists of the following families Family (from la, familia) is a group of people related either by consanguinity (by recognized b ...

** Family

Archechiniscidae ''Archechiniscus'' is the only genus 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 Ephr ...

** Family

Batillipedidae ''Batillipes'' is genus 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 1 ...

** Family

Coronarctidae The Coronarctidae are 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 ...

** Family Halechiniscidae ** Family

Renaudarctidae ''Renaudarctidae'' are a family of tardigrades. It was first described in 1984 by Reinhardt Kristensen Reinhardt Møbjerg Kristensen (born 1948) is a Denmark, Danish invertebrate biologist, noted for the discovery of three new phylum, phyla of ...

** Family

Stygarctidae The Stygarctidae are a family of tardigrades. The family was first described by Schulz in 1951. The genus '' Neoarctus'' was first placed in the family Stygarctidae, but it was moved to a separate family, Neoarctidae ''Neoarctus primigenius'' ...

* Order

Echiniscoidea Echiniscoidea is an order of tardigrades, a phylum of water-dwelling, eight-legged, segmented micro-animals. It was first described by Richters in 1926.

** Family

Echiniscidae The Echiniscidae are a family of tardigrades, a phylum of water-dwelling, eight-legged, segmented micro-animals. It is one of the four families in the order Echiniscoidea.

** Family

Echiniscoididae The Echiniscoididae are a family of tardigrades, water-dwelling, eight-legged, segmented micro-animals. It is one of the four families in the Echiniscoidea order.

** Family

Oreellidae ''Oreella'' is a genus 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 1 ...

Phylum

Arthropoda Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

Spiralia The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. The term ''Spiralia'' is applied to those phyla that exhibit canonical spiral cleavage, a ...
(unranked)

Gnathifera (unranked)

= Phylum
Gnathostomulid Gnathostomulids, or jaw worms, are a small phylum of nearly microscopic marine animals. They inhabit sand and mud beneath shallow coastal waters and can survive in relatively anoxic environments. They were first recognised and described in 1956. ...
a

= No classes * Order

Bursovaginoidea Bursovaginoidea is one of the two orders in the phylum Gnathostomulida. Appearance and anatomy Bursovaginoids are rather small, ranging from a half of a millimeter to a full millimeter in length. Many species in the order Bursovaginoidea have ...

* Order

Filospermoidea Filospermoidea is an order within the phylum Gnathostomulida. Filospermoids are generally longer than gnathostomulids in the order Bursovaginoidea, and have an elongate rostrum. It lives in North America, off the coasts of the southern United Sta ...

= Phylum
Micrognathozoa ''Limnognathia maerski'' is a microscopic freshwater animal, discovered living in warm springs on Disko Island, Greenland, in 1994. Since then, it was also found in Crozet Islands of Antarctica.). With an average length of 100 micrometers ...

= Some dispute here with Micrognathozoa as the class and Limnognathia as the order

= Phylum Cycliophora

= ; Class Eucycliophora * Order Symbiida ** Family Symbiidae *** Genus Symbion

= Syndermata (unranked)

Phylum

Rotifer The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John H ...

; Class

Bdelloidea Bdelloidea (Greek ''βδέλλα'', ''bdella'', "leech") is a class of rotifers found in freshwater habitats all over the world. There are over 450 described species of bdelloid rotifers (or 'bdelloids'), distinguished from each other mainly o ...

* Order

Bdelloida Bdelloidea (Greek ''βδέλλα'', ''bdella'', "leech") is a class of rotifers found in freshwater habitats all over the world. There are over 450 described species of bdelloid rotifers (or 'bdelloids'), distinguished from each other mainly o ...

; Class

Monogononta Monogononta is a class of rotifers, found mostly in freshwater but also in soil and marine environments. They include both free-swimming and sessile forms. Monogononts generally have a reduced corona, and each individual has a single gonad, w ...

* Order Collothecida * Order Flosculariida * Order Ploimida ; Class

Seisonidea Seisonidae is a family of rotifers, found on the gills of ''Nebalia'', a marine crustacean. Peculiar among rotifers, males and females are both present and equal in size. Males and females are similar with paired gonads. It is considered to have ...

* Order

Seisonida Seisonidae is a family of rotifers, found on the gills of ''Nebalia'', a marine crustacean. Peculiar among rotifers, males and females are both present and equal in size. Males and females are similar with paired gonads. It is considered to have ...

Phylum Acanthocephala

; Class Archiacanthocephala * Order Apororhynchida * Order Gigantorhynchida * Order Moniliformida * Order Oligacanthorhynchida ; Class Eoacanthocephala * Order Gyracanthocephala * Order

Neoechinorhynchida Neoechinorhynchida is an order of parasitic worms from the phylum Acanthocephala.Encyclopedia of Life www.eol.org It contains 3 families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or ...

; Class Palaeacanthocephala * Order

Echinorhynchida Echinorhynchida is an order of parasitic worms in the phylum Acanthocephala. It contains the following families: * Arhythmacanthidae Yamaguti, 1935 * Cavisomidae Meyer, 1932 * Diplosentidae Tubangui and Masiluñgan, 1937 *Echinorhynchidae Cobbol ...

* Order

Polymorphida Polymorphida are an order of thorny-headed worms (phylum Acanthocephala). The adults of these parasitic platyzoans feed mainly on fish and aquatic birds. This order contains 5 families:Huston, D. C., Cribb, T. H., & Smales, L. R. (2020). Molec ...

Platytrochozoa (unranked)

= Mesozoa (unranked)

Phylum

Dicyemida Dicyemida, also known as Rhombozoa, is a phylum of tiny parasites that live in the renal appendages of cephalopods. Taxonomy Classification is controversial. Traditionally, dicyemids have been grouped with the Orthonectida in the Mesozoa, an ...

No classes, no orders, families Conocyemidae, Dicyemidae and Kantharellidae

Phylum

Monoblastozoa ''Salinella salve'' is a dubious species of a very simple animal that may not exist, but which some have named as the sole member of the phylum Monoblastozoa. It was discovered in 1892 by Johannes Frenzel in the salt pans of Argentina and cult ...

No classes, no orders, family Salinellidae

Phylum Orthonectida

No classes, no orders, families Pelmatosphaeridae and Rhopaluridae

= Rouphozoa (unranked)

Phylum Platyhelminthes

;;Class

Rhabditophora Rhabditophora (from ''rhabdito''-, rhabdite + Greek -φορος ''phoros'' bearer, i.e., "rhabdite bearers") is a class of flatworms. It includes all parasitic flatworms (clade Neodermata) and most free-living species that were previously groupe ...

*Subclass

Macrostomorpha Macrostomorpha is a clade of free living flatworms ranked either as class or subclass in the group Rhabditophora. There are about 260 described species in two orders - marine, freshwater and brackish Macrostomida, which group most of the species ...

**Order Dolichomicrostomida *Subclass Trepaxonemata **Infraclass

Neoophora Neoophora is a group of rhabditophoran flatworms with ectolecithal eggs, i.e., yolk is not present in the egg as in most animals, but rather is secreted by accessory glands called vitellaria or yolk glands. These glands have the same embryonic o ...

***Parvclass Eulecithophora ****Superorder Adiaphanida *****Order

Fecampiida Fecampiida is an order of flatworms in the class Rhabditophora. It is a considerably recent clade, erected after molecular studies. Description The order Fecampiida, as currently defined, was erected based on molecular studies. They all are pa ...

*****Order Prolecithophora *****Order

Tricladida A planarian is one of the many flatworms of the traditional class Turbellaria. It usually describes free-living flatworms of the order Tricladida (triclads), although this common name is also used for a wide number of free-living platyhelmint ...

****Order

Rhabdocoela Rhabdocoela is an order of flatworms in the class Rhabditophora with about 1700 species described worldwide. The order was first described in 1831 by Christian Gottfried Ehrenberg. Most of rhabdocoels are free-living organisms, but some live symb ...

***Order

Bothrioplanida ''Bothrioplana'' is a genus of freshwater flatworms, the sole genus in the family Bothrioplanidae and order Bothrioplanida. Description Species of ''Bothrioplana'' are small organisms, usually measuring 2–3 mm in length, but reaching up to 7 ...

***Order Lecithoepitheliata ***Order

Proseriata Proseriata is an order of free-living flatworms in the class Rhabditophora with over 400 species described worldwide. Description Proseriate flatworms are minute aquatic organisms, usually with an elongate body. There are no strong synapomorph ...

**Order Gnosonosemida **Order

Polycladida The Polycladida represents a highly diverse clade of free-living marine flatworms. They are known from the littoral to the Sublittoral zone, sublittoral zone (extending to the deep hot vents), and many species are common from coral reefs. Only a ...

**Order Prorhynchida ;Subphylum

Neodermata Neodermata is a clade of rhabditophoran flatworms containing the parasitic groups Trematoda, Monogenea and Cestoda. Description All neodermatans are parasites, in many groups having a free-swimming larval stage. The most striking feature uniti ...

;;Class

Cestoda Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of man ...

*Subclass

Eucestoda Eucestoda, commonly referred to as tapeworms, is the larger of the two Class (biology), subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten ...

**Order

Bothriocephalidea Bothriocephalidea is an order of Cestoda (tapeworms). Members of this order are gut parasites Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host ...

**Order Caryophyllidea **Order Cathetocephalidea **Order

Cyclophyllidea Tapeworms of the order Cyclophyllidea (the cyclophyllid cestodes) are the most important cestode parasites of humans and domesticated animals. All have multiple proglottid "segments", and all have four suckers on their scolices (heads), though ...

**Order

Diphyllidea Diphyllidea is a monotypic taxon, monotypic Order (biology), order of Cestoda (tapeworms). Members of this order are gut Parasitism, parasites of elasmobranch fishes including rays and sharks. References

Cestoda Platyhelminthes orders { ...

**Order

Diphyllobothriidea Diphyllobothriidea is an order of Cestoda (tapeworms). Members of this order are gut parasites of vertebrates. They infect mammals as their definitive hosts and use either copepods (a group of small crustaceans found in the sea and nearly ever ...

**Order Haplobothriidea **Order

Lecanicephalidea Lecanicephaloidea is an order of cestoda, tapeworms of the Class (biology), subclass Cestoda. Species in the order consist of intestinal parasites of elasmobranch fishes. Anatomy The order is distinguished in that the scolex consists of two pa ...

**Order Litobothriidea **Order Nippotaeniidea **Order Onchoproteocephalidea **Order

Phyllobothriidea Phyllobothriidea is an order of flatworms belonging to the class Cestoda. Taxonomy Families: * Chimaerocestidae * Phyllobothriidae Genera: * ''Alexandercestus'' Ruhnke & Workman, 2013 * ''Bibursibothrium'' McKenzie & Caira, 1998 * ''Bilocula ...

**Order

Proteocephalidea ''Proteocephalidea'' is an order of tapeworms which includes the Proteocephalidae family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by mar ...

**Order Pseudophyllidea **Order Rhinebothriidea **Order

Spathebothriidea Spathebothriidea is an order of Cestoda (tapeworms). Members of this order are gut parasites Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host ...

**Order

Tetrabothriidea Tetrabothriidea is an order of helminths in the class Cestoda. It consists of only one family, Tetrabothriidae. Their hosts are mainly seabirds, the rest being cetaceans and pinnipeds. Genera All of the genera of Tetrabothriidea are in the fami ...

**Order

Tetraphyllidea Tetraphyllidea is a large tapeworm order that contains some 60 genera and about 800 described species. Tetraphyllideans are remarkable for their scolex morphologies, which are the most varied and morphologically complex amongst all tapeworm order ...

**Order

Trypanorhyncha ''Trypanorhyncha'' is an order of cestodes, a type of flatworm. Some species infect gamefish, such as sciaenids, during the parasitic worm's plerocercoid stage, and are commonly called spaghetti worm because of their appearance, approximating ...

;;Class

Monogenea Monogeneans are a group of ectoparasitic flatworms commonly found on the skin, gills, or fins of fish. They have a direct lifecycle and do not require an intermediate host. Adults are hermaphrodites, meaning they have both male and female reprod ...

*Subclass Monopisthocotylea **Order

Capsalidea The Monopisthocotylea are a subclass of parasitic flatworms in the class Monogenea. WoRMS (2019). Monopisthocotylea. Accessed at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=119219 on 2019-02-08 Yamaguti, S. (1963). Systema Helminthum V ...

**Order Dactylogyridea **Order Gyrodactylidea **Order

Monocotylidea The Monopisthocotylea are a subclass of parasitic flatworms in the class Monogenea. WoRMS (2019). Monopisthocotylea. Accessed at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=119219 on 2019-02-08 Yamaguti, S. (1963). Systema Helminthum V ...

**Order

Montchadskyellidea The Monopisthocotylea are a subclass of parasitic flatworms in the class Monogenea. WoRMS (2019). Monopisthocotylea. Accessed at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=119219 on 2019-02-08 Yamaguti, S. (1963). Systema Helminthum V ...

*Subclass Polyopisthocotylea **Order Chimaericolidea **Order Diclybothriidea **Order Mazocraeidea **Order Polystomatidea ;;Class

Trematoda Trematoda is a Class (biology), class of flatworms known as flukes. They are obligate parasite, obligate internal Parasitism, parasites with a complex biological life cycle, life cycle requiring at least two Host_(biology), hosts. The intermedia ...

*Subclass

Aspidogastrea The Aspidogastrea (Ancient Greek: ' “shield”, ' “stomach/pouch”) is a small group of Trematoda, flukes comprising about 80 species. It is a Subclass (biology), subclass of the Trematode, trematoda, and sister group to the Digenea. Specie ...

**Order

Aspidogastrida Aspidogastrida is an order of trematodes in the subclass Aspidogastrea. Families *Superfamily Aspidogastrioidea Poche, 1907Poche, F. (1907). Einige Bemerkungen zur Nomenklatur der Trematoden. ''Zoologischer Anzeiger'', 31, 124-126. **Aspidogas ...

**Order

Stichocotylida ''Stichocotyle'' is a monospecific genus of trematodes, in the monospecific family Stichocotylidae, which is itself in the monotypic order Stichocotylida. It comprises the single species ''Stichocotyle nephropis'', which is an internal parasite ...

*Subclass

Digenea Digenea (Gr. ''Dis'' – double, ''Genos'' – race) is a class of trematodes in the Platyhelminthes phylum, consisting of parasitic flatworms (known as ''flukes'') with a syncytial tegument and, usually, two suckers, one ventral and one oral. ...

**Order Diplostomida **Order Plagiorchiida

Phylum

Gastrotricha The gastrotrichs (phylum Gastrotricha), common name, commonly referred to as hairybellies or hairybacks, are a group of microscopic (0.06-3.0 mm), worm-like, acoelomate animals, and are widely distributed and abundant in freshwater and Marin ...

No classes * Order

Chaetonotida The Chaetonotida is an order of gastrotrichs. They generally have a tenpin or bottle-like shape. Chaetonotids inhabit both freshwater and marine environments. They can be distinguished from other gastrotrichs by the absence of pores in the phar ...

* Order

Macrodasyida Macrodasyida is an order (biology), order of gastrotrichs. Members of this order are somewhat worm-like in form, and not more than 1 to 1.5 mm in length. Macrodasyids are almost in entirely marine and live in the sediment in marine or brack ...

= Superphylum
Lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...

Phylum

Mollusca 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 esti ...

Phylum

Annelid 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 ecol ...

{{main, List of Annelid families

Kryptotrochozoa (unranked)

; Phylum Nemertea * Class Anopla ** Order Heteronemertea ** Order Palaeonemertea * Class Enopla ** Order Bdellonemertea ** Order

Hoplonemertea Hoplonemertea is an order of ribbon worms in the class Enopla. It contains two suborders: * Monostilifera * Polystilifera The proboscis is armed with one or more stylets; intestine straight, mostly with paired lateral diverticula; no post ...

; Lophophorata (unranked) *

Brachiozoa Brachiozoa is a grouping of lophophorate animals including Brachiopoda and Phoronida. It also includes their ancestors, the extinct tommotiids. References Lophophorata Protostome unranked clades {{Protostome-stub ...

(unranked) ** Phylum

Hyolitha Hyoliths are animals with small conical shells, known as fossils from the Palaeozoic era. They are at least considered as lophotrochozoan, and possibly being lophophorates, a group which includes the brachiopods, while others consider them as be ...

† *** Order Hyolithida *** Order Orthothecida ** Phylum Brachiopoda *** Class

Lingulata Lingulata is a class of brachiopods, among the oldest of all brachiopods having existed since the Cambrian period (). They are also among the most morphologically conservative of the brachiopods, having lasted from their earliest appearance to the ...

**** Order

Lingulida Lingulida is an order of brachiopods. Extinct species The following are extinct species and genera belonging to the family Lingulidae.Emig C. C., Bitner M. A. & Álvarez F., 2019Linguliformea Brachiopoda database. Accessed 2020-09-27. *'' Lin ...

**** Order

Discinida Discinida is an order of brachiopods comprising the extant superfamily Discinoidea, and the extinct superfamilies Botsfordioidea (early—mid-Cambrian) and Acrotheloidea (early Cambrian–Early Ordovician). It represents a sister taxon to the ...

*** Class Craniata/Craniforma **** Order Craniida *** Class

Rhynchonellata The Rhynchonellata is a class of Lower Cambrian to Recent articulate brachiopods that combines orders from within the Rhynchonelliformea (Articulata revised) with well developed pedicle attachment. Shell forms vary from those with wide hinge li ...

**** Order

Terebratulida Terebratulids are one of only three living orders of articulate brachiopods, the others being the Rhynchonellida and the Thecideida. Craniida and Lingulida include living brachiopods, but are inarticulates. The name, Terebratula, may be derived f ...

**** Order Rhynchonellida ** Phylum

Phoronid Phoronids (scientific name Phoronida, sometimes called horseshoe worms) are a small phylum of marine animals that filter-feed with a lophophore (a "crown" of tentacles), and build upright tubes of chitin to support and protect their soft bodies. ...

a No classes, no orders, family Phoronidae *

Bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...

(unranked) ** Phylum

Ectoprocta Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...

*** Class

Gymnolaemata Gymnolaemata are a class of Bryozoans. Gymnolaemata are sessile, mostly marine organisms and grow on the surfaces of rocks, kelp, and in some cases on animals, like fish. Zooids are cylindrical or flattened. The lophophore is protruded by action ...

**** Order

Cheilostomata Cheilostomatida, also called Cheilostomata, is an order of Bryozoa in the class Gymnolaemata. They are exclusively marine, colonial invertebrate animals. Cheilostome colonies are composed of calcium carbonate and grow on a variety of surfaces, ...

**** Order Ctenostomatida *** Class

Phylactolaemata Phylactolaemata is a class of the phylum Bryozoa whose members live only in freshwater environments. Like all bryozoans, they filter feed by means of an extensible "crown" of ciliated tentacles called a lophophore, and like nearly all bryozoans ( ...

**** Order

Plumatellida Phylactolaemata is a class of the phylum Bryozoa whose members live only in freshwater environments. Like all bryozoans, they filter feed by means of an extensible "crown" of ciliated tentacles called a lophophore, and like nearly all bryozoans ...

*** Class

Stenolaemata Stenolaemata are a class of exclusively marine bryozoans. Stenolaemates originated and diversified in the Ordovician, and more than 600 species are still alive today.Cryptostomata Cryptostomata is an order of fossil bryozoans that lived from the Ordovician to the Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous P ...

† **** Order Cryptostomida † **** Order Cyclostomatida **** Order

Cystoporata Cystoporata, also known as Cystoporida or cystoporates, are an extinct order of Paleozoic bryozoans in the class Stenolaemata. Their fossils are found from Ordovician to Triassic strata. All cystoporatan bryozoan genera (around 50 or so) have ...

† **** Order

Cystoporida Cystoporata, also known as Cystoporida or cystoporates, are an extinct order of Paleozoic bryozoans in the class Stenolaemata. Their fossils are found from Ordovician to Triassic strata. All cystoporatan bryozoan genera (around 50 or so) have ...

† **** Order Esthonioporata † **** Order

Fenestrida Fenestrida is an extinct order of bryozoans in the class Stenolaemata. , Fossilworks included the following families: *† Admiratellidae *†Fenestellidae *† Fenestraliidae *† Polyporidae *† Septoporidae Other sources consider ''Fenestrat ...

† **** Order Hederellida † **** Order Melicerititida † **** Order Rhabdomesida † **** Order

Trepostomatida Trepostomatida (the trepostomates) is an extinct order of bryozoans in the class Stenolaemata. Trepostome bryozoans possessed mineralized calcitic skeletons and are frequently fossilized; some of the largest known fossilized bryozoan colonies ...

† ** Phylum

Entoprocta Entoprocta (), or Kamptozoa , is a phylum of mostly sessile aquatic animals, ranging from long. Mature individuals are goblet-shaped, on relatively long stalks. They have a "crown" of solid tentacles whose cilia generate water currents that d ...

No classes, no orders, families Barentsiidae, Loxokalypodidae, Loxosomatidae and Pedicellinidae

References

Bilateral animals Bilaterian

Phylum Xenacoelomorpha Xenacoelomorpha is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2011 and suggested based on morphological synapomorphies (physical app ...

Nephrozoa (unranked)

Infrakingdom Deuterostomia Deuterostomia (; in Greek) are animals typically characterized by their anus forming before their mouth during embryonic development. The group's sister clade is Protostomia, animals whose digestive tract development is more varied. Some ex ...

Phylum Chordata A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fiv ...

Ambulacraria Ambulacraria , or Coelomopora , is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member of this group is called an ambulacrarian. Phylogenetic analysis suggests the echinoderms and hemichordates separated around 533 ...

Phylum Hemichordata

Phylum Echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea ...ata

Infrakingdom Protostomia Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's mem ...

Superphylum Ecdysozoa Ecdysozoa () is a group of protostome animals, including Arthropoda (insects, chelicerata, crustaceans, and myriapods), Nematoda, and several smaller phyla. They were first defined by Aguinaldo ''et al.'' in 1997, based mainly on phylogenetic tr ...

Cycloneuralia Cycloneuralia is a clade of ecdysozoan animals including the Scalidophora (Kinorhynchans, Loriciferans, Priapulids) and the Nematoida (nematodes, Nematomorphs). It may be paraphyletic, or may be a sister group to Panarthropoda. Or perhaps Pana ... (unranked)

= Scalidophora (unranked)

= Nematoida Nematoida is a grouping of animals, including the roundworms The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known ... (unranked)

Panarthropoda Panarthropoda is a proposed animal clade containing the extant phyla Arthropoda, Tardigrada (water bears) and Onychophora (velvet worms). Panarthropods also include extinct marine legged worms known as lobopodians ("Lobopodia"), a paraphyletic g ... (unranked)

= Phylum Lobopodia †

= Phylum Onychophora

= Tactopoda Tactopoda is a proposed clade of protostome animals that includes the phyla Tardigrada and Euarthropoda, supported by various morphological observations. The cladogram below shows the relationships implied by this hypothesis. The competing hyp ... (unranked)

Spiralia The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. The term ''Spiralia'' is applied to those phyla that exhibit canonical spiral cleavage, a ... (unranked)

Gnathifera (unranked)

= Phylum Gnathostomulid Gnathostomulids, or jaw worms, are a small phylum of nearly microscopic marine animals. They inhabit sand and mud beneath shallow coastal waters and can survive in relatively anoxic environments. They were first recognised and described in 1956. ...a

= Phylum Micrognathozoa ''Limnognathia maerski'' is a microscopic freshwater animal, discovered living in warm springs on Disko Island, Greenland, in 1994. Since then, it was also found in Crozet Islands of Antarctica.). With an average length of 100 micrometers ...

= Phylum Cycliophora

= Syndermata (unranked)

Platytrochozoa (unranked)

= Mesozoa (unranked)

= Rouphozoa (unranked)

= Superphylum Lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...

References

Phylum
Xenacoelomorpha Xenacoelomorpha is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2011 and suggested based on morphological synapomorphies (physical app ...

Infrakingdom
Deuterostomia Deuterostomia (; in Greek) are animals typically characterized by their anus forming before their mouth during embryonic development. The group's sister clade is Protostomia, animals whose digestive tract development is more varied. Some ex ...

Phylum
Chordata A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fiv ...

Phylum
Echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea ...
ata

Infrakingdom
Protostomia Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's mem ...

Superphylum
Ecdysozoa Ecdysozoa () is a group of protostome animals, including Arthropoda (insects, chelicerata, crustaceans, and myriapods), Nematoda, and several smaller phyla. They were first defined by Aguinaldo ''et al.'' in 1997, based mainly on phylogenetic tr ...

Cycloneuralia Cycloneuralia is a clade of ecdysozoan animals including the Scalidophora (Kinorhynchans, Loriciferans, Priapulids) and the Nematoida (nematodes, Nematomorphs). It may be paraphyletic, or may be a sister group to Panarthropoda. Or perhaps Pana ...
(unranked)

=
Nematoida Nematoida is a grouping of animals, including the roundworms The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known ...
(unranked)

Panarthropoda Panarthropoda is a proposed animal clade containing the extant phyla Arthropoda, Tardigrada (water bears) and Onychophora (velvet worms). Panarthropods also include extinct marine legged worms known as lobopodians ("Lobopodia"), a paraphyletic g ...
(unranked)

=
Tactopoda Tactopoda is a proposed clade of protostome animals that includes the phyla Tardigrada and Euarthropoda, supported by various morphological observations. The cladogram below shows the relationships implied by this hypothesis. The competing hyp ...
(unranked)

Spiralia The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa. The term ''Spiralia'' is applied to those phyla that exhibit canonical spiral cleavage, a ...
(unranked)

= Phylum
Gnathostomulid Gnathostomulids, or jaw worms, are a small phylum of nearly microscopic marine animals. They inhabit sand and mud beneath shallow coastal waters and can survive in relatively anoxic environments. They were first recognised and described in 1956. ...
a

= Phylum
Micrognathozoa ''Limnognathia maerski'' is a microscopic freshwater animal, discovered living in warm springs on Disko Island, Greenland, in 1994. Since then, it was also found in Crozet Islands of Antarctica.). With an average length of 100 micrometers ...

= Superphylum
Lophotrochozoa Lophotrochozoa (, "crest/wheel animals") is a clade of protostome animals within the Spiralia. The taxon was established as a monophyletic group based on molecular evidence. The clade includes animals like annelids, molluscs, bryozoans, brachi ...