Bilateria is an extremely diverse group of animals containing a vast majority of its species, largely due to the enormous amount of arthropods. This article is a list of orders contained within Bilateria separated by phylum. Groups that are not contained within an order are listed separately.

List Phylum Annelida

Annelid taxonomy is currently under constant revisions due to the discovery that the class Polychaeta is paraphyletic. As such, a comprehensive list of orders is likely to change depending on what is accepted as valid.

Amphinomida Class Sipuncula Aspidosiphonida Golfingiida Phascolosomatida Clade Pleistoannelida Clade Errantia Eunicida Phyllodocida Protodrilida Myzostomida Clade Sedentaria Capitellida Family Capitellidae Subclass Echiura Bonelliida Echiurida Opheliida Orbiniida Sabellida Spionida Terebellida Class Clitellata Branchiobdellida Haplotaxida Lumbriculida Moniligastrida Subclass Hirudinea Rhynchobdellida Arhynchobdellida Unplaced groups Genus Apistobranchus Suborder Chaetopteriformia Suborder Cirratuliformia Genus Lobatocerebrum Clade Maldanomorpha Clade Paleoannelida Family Polygordiidae Family Siboglinidae Phylum Arthropoda

See List of arthropod orders Phylum Brachiopoda

Class Craniata Craniida Craniopsida † Trimerellida † Subphylum Linguliformea Class Lingulata Acrotretida † Lingulida Siphonotretida † Class Paterinata Paterinida † Subphylum Rhynchonelliformea Class Chileata Chileida † Dictyonellida † Class Kutorginata Kutorginida † Class Obolellata Naukatida † Obolellida † Class Rhynchonellata Athyridida † Atrypida † Orthida † Protorthida † Pentamerida † Rhynchonellida Spiriferida † Terebratulida Thecideida Class Strophomenata Billingsellida † Orthotetida † Productida † Strophomenida † Phylum Bryozoa

Class Gymnolaemata Cheilostomata Ctenostomatida Class Phylactolaemata Plumatellida Class Stenolaemata Cyclostomatida Cryptostomata † Cystoporida † Esthonioporata † Fenestrida † Timanodictyina † Trepostomatida † Phylum Chaetognatha

Aphragmophora Phragmophora Protoconodonta † Unplaced groups Genus Capinatator Genus Eognathacantha Genus Protodagitta Genus Timorebestia Phylum Chordata

See List of chordate orders Phylum Cycliophora

Class Eucycliophora Symbiida Phylum Dicyemida

Dicyemida does not contain any established orders but does contain three families: Conocyemidae, Dicyemidae and Kantharellidae. Phylum Echinodermata

See List of echinoderm orders Phylum Entoprocta

Entoprocta has no orders but is split into four families; Barentsiidae, Pedicellinidae, Loxokalypodidae, and Loxosomatidae. Phylum Gastrotricha

Chaetonotida Macrodasyida Phylum Gnathostomulida

Bursovaginoidea Filospermoidea Phylum Hemichordata

The classes Planctosphaeroidea and Enteropneusta do not contain any orders.

Class Pterobranchia Cephalodiscida Subclass Graptolithina Rhabdopleurida Dendroidea † Graptoloidea †

Unplaced groups Family Cysticamaridae Family Wimanicrustidae Family Dithecodendridae Family Cyclograptidae Phylum Kinorhyncha

Class Cyclorhagida Echinorhagata Kentrorhagata Xenosomata Class Allomalorhagida Anomoirhaga Unplaced groups Genus Eokinorhynchus Family Pycnophyidae Phylum Loricifera

Loricifera has no classes and all species are contained within one order. Nanaloricida Phylum Micrognathozoa

Micrognathozoa has no classes. Its two species are placed in one order. Limnognathida Phylum Mollusca

See List of mollusc orders Phylum Nematoda

Nematode taxonomy is far from fully resolved, and different schemes might be used. For this list, Mike Hodda's Phylum Nematoda: a classification, catalogue and index of valid genera, with a census of valid species classification is used.

Class Enoplea Subclass Enoplia Superorder Enoplica Alaimida Enoplida Ironida Trefusiida Tripyloidida Superorder Rhaptothyreica Rhaptothyreida Subclass Oncholaimia Oncholaimida Subclass Triplonchia Triplonchida Tripylida Class Dorylaimea Subclass Dorylaimia Dorylaimida Subclass Bathyodontia Bathyodontida Mononchida Mermithida Subclass Trichocephalia Trichocephalida Marimermithida Dioctophymatida Muspiceida Class Chromadorea Subclass Chromadoria Chromadorida Selachinematida Desmodorida Desmoscolecida Subclass Plectia Superorder Monhysterica Monhysterida Superorder Plectica Leptolaimida Plectida Benthimermithida Superorder Teratocephalica Teratocephalida Superorder Rhabditica Diplogasterida Rhabditida Spirurida Rhigonematida Panagrolaimida Drilonematida Phylum Nematomorpha

Gordioidea Nectonematoidea Phylum Nemertea

Class Hoplonemertea Monostilifera Polystilifera Class Palaeonemertea Archinemertea Carinomiformes Tubulaniformes Class Pilidiophora Heteronemertea Phylum Onychophora

Onychophora contains no classes and no orders, but is split into two living families; Peripatidae and Peripatopsidae, and 5 extinct genera; Antennacanthopodia, Antennipatus, Helenodora, Succinipatopsis, and Tertiapatus. Phylum Orthonectida

Orthonectida contains no classes or orders, but is split into two families; Pelmatosphaeridae and Rhopaluridae. Phylum Phoronida

Phoronida contains no classes, orders, or families, but is split into two genera; Phoronis and Phoronopsis. Phylum Platyhelminthes

The class Catenulida contains no orders.

Subphylum Rhabditophora Clade Macrostomorpha Macrostomida Clade Trepaxonemata Gnosonesimida Clade Amplimatricata Lecithoepitheliata Polycladida Clade Euneoophora Proseriata Rhabdocoela Clade Acentrosomata Clade Adiaphanida Prolecithophora Fecampiida Tricladida Clade Bothrioneodermata Bothrioplanida Superclass Neodermata Class Cestoda Subclass Cestodaria Amphilinidea Gyrocotylidea Subclass Eucestoda Spathebothriidea Caryophyllidea Haplobothriidea Diphyllobothriidea Diphyllidea Trypanorhyncha Bothriocephalidea Litobothriidea Lecanicephaloidea Rhinebothriidea Tetraphyllidea Onchoproteocephalidea Nippotaeniidea Tetrabothriidea Cyclophyllidea Class Monogenea Subclass Monopisthocotylea Monocotylidea Capsalidea Lagarocotylidea Montchadskyellidea Gyrodactylidea Dactylogyridea Subclass Polyopisthocotylea Polystomatidea Chimaericolidea Diclybothriidea Mazocraeidea Class Trematoda Subclass Aspidogastrea Aspidogastrida Stichocotylida Subclass Digenea Diplostomida Plagiorchiida

Unplaced groups Genus Haplopharynx Phylum Priapulida

Several stem group priapulid genera are not classified within any established orders. The orders listed below are solely crown priapulids.

Halicryptomorphida Priapulimorphida Meiopriapulomorpha Seticoronaria Phylum Rotifera

The group Acanthocephala is traditionally treated as a separate phylum from Rotifera. However, it was found that Acanthocephala are phylogenetically contained within the rotifers, and this list reflects these findings.

Seisonida Superclass Eurotatoria Class Bdelloidea Adinetida Philodinavida Philodinida Class Monogononta Collothecaceae Flosculariaceae Ploima Clade Acanthocephala Class Archiacanthocephala Apororhynchida Gigantorhynchida Moniliformida Oligacanthorhynchida Class Eoacanthocephala Gyracanthocephala Neoechinorhynchida Class Palaeacanthocephala Echinorhynchida Heteramorphida Polymorphida Polyacanthorhynchida

Phylum Tardigrada

The class Mesotardigrada contains one species, Thermozodium esakii, which has not been found since its reported discovery in 1937, and its existence is dubious. It is contained within the order Thermozodia.

Class Eutardigrada Apochela Parachela Class Heterotardigrada Arthrotardigrada Echiniscoidea Phylum Xenacoelomorpha

The subphylum Xenoturbellida does not contain any classes or orders. Its only family is Xenoturbellidae which contains one genus, Xenoturbella. Subphylum Acoelomorpha Acoela

The class Nemertodermatida does not contain any orders, but does contain two families; Ascopariidae and Nemertodermatidae.

Notes

References