List of bilaterian orders


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.
Class Sipuncula
Clade Pleistoannelida
Unplaced groups

Phylum [Arthropoda]

See List of arthropod orders

Phylum [Brachiopoda]

Class Craniata
Subphylum Linguliformea
Subphylum Rhynchonelliformea

Phylum [Bryozoa]

Class Gymnolaemata
Class Phylactolaemata
Class Stenolaemata

Phylum [Chaetognatha]

Unplaced groups

Phylum [Chordata]

See List of chordate orders

Phylum [Cycliophora]

Class Eucycliophora

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]

Phylum [Gnathostomulida]

Phylum [Hemichordata]

The classes Planctosphaeroidea and Enteropneusta do not contain any orders
Class Pterobranchia
Unplaced groups

Phylum [Kinorhyncha]

Class Cyclorhagida
Class Allomalorhagida
  • Anomoirhaga
Unplaced groups

Phylum [Loricifera]

Loricifera has no classes and all species are contained within one order

Phylum [Micrognathozoa]

Micrognathozoa has no classes and its single species is placed in one order

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
Class Chromadorea

Phylum [Nematomorpha]

Phylum [Nemertea]

Class Hoplonemertea
Class Palaeonemertea
Class Pilidiophora

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
Unplaced groups

Phylum [Priapulida]

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

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.
Superclass Eurotatoria
Clade Acanthocephala

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.

Phylum [Xenacoelomorpha]

The subphylum Xenoturbellida does not contain any classes or orders. Its only family is Xenoturbellidae which contains one genus, Xenoturbella.
The class Nemertodermatida does not contain any orders, but does contain two families; Ascopariidae and Nemertodermatidae.