Taxonomy of invertebrates (Brusca & Brusca, 2003)

The biological systematics and taxonomy of invertebrates as proposed by Richard C. Brusca and Gary J. Brusca in 2003 is a system of classification of invertebrates, as a way to classify animals without backbones.

Prokaryotes

 * Kingdom
 * Kingdom

Eukaryotes (Eukaryota, or Eukarya)

 * Kingdom
 * Kingdom (= Metaphyta)
 * Kingdom
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Phylum
 * Incertae sedis: Genus
 * Incertae sedis: Genus

Phylum Porifera

 * Phylum Porifera
 * Class Calcarea
 * Subclass Calcinea
 * Subclass Calcaronea
 * Class Hexactinellida
 * Subclass Amphidiscophora
 * Subclass Hexasterophora
 * Class Demospongiae
 * Subclass Homoscleromorpha
 * Subclass Tetractinomorpha
 * Subclass Ceractinomorpha

Phylum Placozoa

 * Phylum Placozoa
 * Trichoplax adhaerens

Phylum Monoblastozoa

 * Phylum Monoblastozoa
 * Salinella

Phylum Rhombozoa

 * Phylum Rhombozoa
 * Order Dicyemida
 * Order Heterocyemida

Phylum Orthonectida

 * Phylum Orthonectida

Phylum Cnidaria

 * Phylum Cnidaria
 * Class Hydrozoa
 * Order Hydroida
 * Suborder Anthomedusae (= Gymnoblastea or Athecata)
 * Suborder Leptomedusae (= Calyptoblastea or Thecata)
 * Order Trachylina
 * Order Siphonophora
 * Order Chondrophora
 * Order Actinulida
 * Class Anthozoa
 * Subclass Octocorallia (= Alcyonaria)
 * Order Alcyonacea
 * Order Gastraxonacea
 * Order Gorgonacea
 * Order Helioporacea
 * Order Pennatulacea
 * Order Protoalcyonaria
 * Order Stolonifera
 * Order Telestacea
 * Subclass Hexacorallia (= Zoantharia)
 * Order Actiniaria
 * Order Scleractinia (= Madreporaria)
 * Order Zoanthidea
 * Order Corallimorpharia
 * Subclass Ceriantipatharia
 * Order Antipatharia
 * Order Ceriantharia
 * Class Cubozoa
 * Class Scyphozoa
 * Order Stauromedusae
 * Order Coronatae
 * Order Semaeostomae
 * Order Rhizostomae

Phylum Ctenophora

 * Phylum Ctenophora
 * Order Beroida
 * Order Cestida
 * Order Cydippida
 * Order Ganeshida
 * Order Lobata
 * Order Platyctenida
 * Order Thalassocalycida

Bilateria
The authors divide the bilaterians in three informal groups:
 * acoelomates (phyla Platyhelminthes, Gastrotricha, Entoprocta, Gnathostomulida, Cycliophora)
 * blastocoelomate (or pseducoelomate, phyla Rotifera, Kinorhyncha, Nematoda, Nematomorpha, Acanthocephala, Loricifera)
 * coelomates (or eucoelomates, phyla Nemertea, Priapula, Annelida, Sipuncula, Echiura, Onychophora, Tardigrada, Arthropoda, Mollusca, Phoronida, Ectoprocta, Brachiopoda, Echinodermata, Chaetognatha, Hemichordata, Chordata).

Several groups traditionally viewed as having a blastocoelomate condition are viewed here as acoelomates (e.g., Gastrotricha, Entoprocta, Gnathostomulida).

Some of the coelomates groups (e.g., Arthropoda, Mollusca) have greatly reduced celomic spaces; often the main body cavity is a bloodfilled space called a hemocoel, and is associated with an open circulatory system.

The Brachiopoda, Ectoprocta and Phoronida are viewed as lophophorates.

In a phylogeny, the bilaterians are divided in:
 * Protostomia
 * Cycloneuralia
 * Loricifera
 * Kinorhyncha
 * Priapula
 * Nematomorpha
 * Nemata
 * Gastrotricha
 * Acanthocephala
 * Rotifera
 * Cycliophora
 * Entoprocta
 * Gnathostomulida
 * Articulata
 * Arthropoda
 * Tardigrada
 * Onychophora
 * Annelida
 * Echiura
 * Mollusca
 * Sipuncula
 * Nemertea
 * Platyhelminthes


 * Deuterostomia
 * Chordata
 * Vertebrata
 * Cephalochordata
 * Urochordata
 * Hemichordata
 * Pterobranchia
 * Enteropneusta
 * Echinodermata
 * Chaetognatha
 * Brachiopoda
 * Ectoprocta
 * Phoronida

Phylum Platyhelminthes

 * Phylum Platyhelminthes
 * Class Turbellaria
 * Order Acoela
 * Order Catenulida
 * Order Haplopharyngida
 * Order Lecithoepitheliata
 * Order Macrostomida
 * Order Nemertodermatida
 * Order Polycladida
 * Order Prolecithophora
 * Order Proplicastomata
 * Order Proseriata
 * Order Rhabdocoela
 * Suborder Dalyellioida
 * Suborder Thyphloplanoida
 * Suborder Kalyptorhynchia
 * Suborder Temnocephalida
 * Order Tricladida
 * Class Monogenea
 * Subclass Monopisthocotylea
 * Subclass Polyopisthocotylea
 * Class Trematoda
 * Subclass Digenea
 * Subclass Aspidogastrea
 * Class Cestoda
 * Subclass Cestodaria
 * Subclass Eucestoda

Phylum Nemertea

 * Phylum Nemertea
 * Class Anopla
 * Class Enopla

Phylum Rotifera

 * Phylum Rotifera
 * Class Digonata
 * Order Seisonidea
 * Order Bdelloidea
 * Class Monogononta

Phylum Gastrotricha

 * Phylum Gastrotricha
 * Order Macrodasyida
 * Order Chaetonotida
 * Suborder Multitubulatina
 * Suborder Paucitubulatina

Phylum Kinorhyncha

 * Phylum Kinorhyncha
 * Order Cyclorhagida
 * Order Homalorhagida

Phylum Nematoda (= Nemata)

 * Phylum Nematoda (= Nemata)
 * Class Adenophorea (= Aphasmida)
 * Subclass Enoplia
 * Subclass Chromadoria
 * Class Secernentea (= Phasmida)
 * Subclass Rhabditia
 * Subclass Spiruria
 * Subclass Diplogasteria

Phylum Nematomorpha

 * Phylum Nematomorpha
 * Order Nectonematoidea
 * Order Gordioidea

Phylum Priapula

 * Phylum Priapula
 * Family Priapulidae
 * Family Tubiluchidae
 * Family Maccabeidae (= Chaetostephanidae)

Phylum Acanthocephala

 * Phylum Acanthocephala
 * Class Palaeacanthocephala
 * Class Archiacanthocephala
 * Class Eoacanthocephala

Phylum Entoprocta (= Kamptozoa)

 * Phylum Entoprocta (= Kamptozoa)
 * Family Loxosomatidae
 * Family Loxokalypodidae
 * Family Pedicellinidae
 * Family Barentsiidae

Phylum Gnathostomulida

 * Phylum Gnathostomulida
 * Order Filospermoidea
 * Order Bursovaginoidea

Phylum Loricifera

 * Phylum Loricifera
 * Order Nanaloricida
 * Family Nanaloricidae
 * Family Pliciloricidae

Phylum Cycliophora

 * Phylum Cycliophora
 * Symbion pandora

Phylum Annelida

 * Phylum Annelida
 * Class Polychaeta, with 25 orders and 87 families (not all are listed)
 * Order Capitellida
 * Order Chaetopterida
 * Order Cirratulida
 * Order Eunicida
 * Order Myzostomida
 * Order Opheliida
 * Order Spionida
 * Order Orbiniida
 * Order Oweniida
 * Order Phyllodocida
 * Order Sabellida
 * Order Terebellida
 * Class Clitellata
 * Subclass Oligochaeta
 * Order Lumbriculida
 * Family Lumbriculidae
 * Order Moniligastrida
 * Family Moniligastridae
 * Order Haplotaxida, with 25 families (not all are listed)
 * Family Almidae
 * Family Megascolecidae
 * Family Tubificidae
 * Family Naididae
 * Family Lumbricidae
 * Subclass Hirudinoidea
 * Order Acanthobdellida
 * Order Branchiobdellida
 * Order Hirudinida

Phylum Sipuncula

 * Phylum Sipuncula
 * Class Phascolosomida
 * Order Aspidosiphoniformes
 * Order Phascolosomiformes
 * Class Sipunculida
 * Order Golfingiaformes
 * Family Themistidae
 * Family Phascolionidae
 * Family Golfingiidae
 * Order Sipunculiformes

Phylum Echiura

 * Phylum Echiura
 * Order Echiuroinea
 * Order Xenopneusta
 * Order Heteromyota

Phylum Onychophora

 * Phylum Onychophora
 * Family Peripatidae
 * Family Peripatopsidae

Phylum Tardigrada

 * Phylum Tardigrada
 * Order Heterotardigrada
 * Order Mesotardigrada
 * Order Eutardigrada

Phylum Arthropoda

 * Phylum Arthropoda
 * Subphylum Trilobitomorpha
 * Subphylum Crustacea
 * Class Remipedia
 * Class Cephalocarida
 * Class Branchiopoda
 * Order Anostraca
 * Order Notostraca
 * Order Diplostraca
 * Suborder Laevicaudata
 * Suborder Spinicaudata
 * Suborder Cyclestherida
 * Suborder Cladocera
 * Class Malacostraca
 * Subclass Phyllocarida
 * Order Lepstostraca
 * Subclass Eumalacostraca
 * Superorder Hoplocarida
 * Order Stomatopoda
 * Superorder Syncarida
 * Order Bathynellacea
 * Order Anaspidacea
 * Superorder Eucarida
 * Order Euphausiacea
 * Order Amphionidacea
 * Order Decapoda
 * Suborder Dendrobranchiata
 * Suborder Pleocyemata
 * Infraorder Caridea
 * Infraorder Stenopodidea
 * Infraorder Brachyura
 * Infraorder Anomura
 * Infraorder Astacidea
 * Infraorder Palinura
 * Infraorder Thalassinidea
 * Superorder Peracarida
 * Order Mysida
 * Order Lophogastrida
 * Order Cumacea
 * Order Tanaidacea
 * Order Mictacea
 * Order Spelaeogriphacea
 * Order Thermosbaenacea
 * Order Isopoda
 * Suborder Anthuridea
 * Suborder Asellota
 * Suborder Calabozoidea
 * Suborder Epicaridea
 * Suborder Flabellifera
 * Suborder Gnathiidea
 * Suborder Oniscidea
 * Suborder Phreatoicidea
 * Suborder Valvifera
 * Order Amphipoda
 * Suborder Gammaridea
 * Suborder Hyperiidea
 * Suborder Caprellidea
 * Suborder Ingolfiellidea
 * Class Maxillopoda
 * Subclass Thecostraca
 * Infraclass Facetotecta
 * Infraclass Ascothoracida
 * Infraclass Cirripedia
 * Superorder Acrothoracica
 * Superorder Rhizocephala
 * Superorder Thoracica
 * Subclass Tantulocarida
 * Subclass Branchiura
 * Subclass Pentastomida
 * Subclass Mystacocarida
 * Subclass Copepoda
 * Infraclass Progymnoplea
 * Order Platycopioida
 * Infraclass Neocopepoda
 * Order Calanoida
 * Order Cyclopoida
 * Order Gelyelloida
 * Order Harpacticoida
 * Order Misophrioida
 * Order Monstrilloida
 * Order Mormonilloida
 * Order Poecilostomatoida
 * Order Siphonostomatoida
 * Subclass Ostracoda
 * Superorder Myodocopa
 * Order Myodocopida
 * Order Halocyprida
 * Superorder Podocopa
 * Order Podocopida
 * Order Platycopida
 * Order Palaeocopida
 * Subphylum Hexapoda
 * Class Entognatha
 * Order Collembola
 * Order Protura
 * Order Diplura
 * Class Insecta
 * Subclass Archaeognatha
 * Order Archaeognatha (= Microcoryphia)
 * Subclass Zygentoma
 * Order Thysanura
 * Subclass Pterygota
 * Infraclass Palaeoptera
 * Order Ephemeroptera
 * Order Odonata
 * Infraclass Neoptera
 * Order Plecoptera
 * Order Blattodea
 * Order Isoptera
 * Order Mantodea
 * Order Phasmida (= Phasmatoptera)
 * Order Grylloblattodea
 * Order Dermaptera
 * Order Orthoptera
 * Order Mantophasmatodea
 * Order Embioptera
 * Order Zoraptera
 * Order Psocoptera
 * Order Phthiraptera
 * Order Thysanoptera
 * Order Hemiptera
 * Order Strepsiptera
 * Order Megaloptera
 * Order Raphidioptera
 * Order Neuroptera
 * Order Coleoptera
 * Order Mecoptera
 * Order Siphonaptera
 * Order Diptera
 * Order Trichoptera
 * Order Lepidoptera
 * Order Hymenoptera
 * Subphylum Myriapoda
 * Class Diplopoda
 * Subclass Penicillata
 * Order Polyxenida
 * Subclass Chilognatha
 * Order Callipodida
 * Order Chordeumatida
 * Order Glomerida
 * Order Glomeridesmida
 * Order Julida
 * Order Platydesmida
 * Order Polydesmida
 * Order Polyzoniida
 * Order Siphonophorida
 * Order Siphoniulida
 * Order Sphaerotheriida
 * Order Spirobolida
 * Order Spirostreptida
 * Order Stemmiulida
 * Class Chilopoda
 * Subclass Notostigmophora
 * Order Scutigeromorpha
 * Subclass Pleurostigmophora
 * Order Craterostigmomorpha
 * Order Geophilomorpha
 * Order Lithobiomorpha
 * Order Scolopendromorpha
 * Class Pauropoda
 * Class Symphyla
 * Subphylum Cheliceriformes
 * Class Pycnogonida
 * Class Chelicerata
 * Subclass Merostomata
 * Order Eurypterida
 * Order Xiphosura
 * Subclass Arachnida
 * Order Acari
 * Suborder Opiloacarifomes
 * Suborder Parasitiformes
 * Suborder Acariformes
 * Order Amblypygi
 * Order Araneae
 * Suborder Mesothelae
 * Suborder Opisthothelae
 * Superfamily Mygalomorpha
 * Family Ctenizidae
 * Family Atypidae
 * Family Theraphosidae
 * Family Dipluridae
 * Superfamily Araneomorphae
 * Family Loxoscelidae
 * Family Theridiidae
 * Family Uloboridae
 * Family Araneidae
 * Family Tetragnathidae
 * Family Clubionidae
 * Family Linyphiidae
 * Family Agelenidae
 * Family Argyronetidae
 * Family Lycosidae
 * Family Pisauridae
 * Family Oxyopidae
 * Family Thomisidae
 * Family Heteropodidae
 * Family Salticidae
 * Family Dinopidae
 * Family Scytodidae
 * Order Opiliones
 * Order Palpigradi
 * Order Pseudoscorpionida
 * Order Ricinulei
 * Order Schizomida
 * Order Scorpiones
 * Order Solpugida
 * Order Uropygi

Phylum Mollusca

 * Phylum Mollusca
 * Class Aplacophora
 * Subclass Chaetodermomorpha (= Caudofoveata)
 * Subclass Neomeniomorpha (= Solenogastres)
 * Class Monoplacophora
 * Class Polyplacophora
 * Order Lepidopleurida
 * Order Ischnochitonida
 * Order Acanthochitonida
 * Class Gastropoda
 * Subclass Prosobranchia
 * Order Archaeogastropoda
 * Order Mesogastropoda
 * Order Neogastropoda
 * Subclass Opisthobranchia
 * Order Acochlidioidea
 * Order Cephalaspidea
 * Order Runcinoidea
 * Order Sacoglossa
 * Order Anaspidea
 * Order Thecosomata
 * Order Gymnosomata
 * Order Notaspidea
 * Order Nudibranchia
 * Subclass Pulmonata
 * Order Archaeopulmonata
 * Order Basommatophora
 * Order Stylommatophora
 * Order Systellommatophora
 * Class Bivalvia (=Pelecypoda, or Lamellibranchiata)
 * Subclass Protobranchia
 * Order Nuculida (= Palaeotaxodonta)
 * Order Solemyida (= Cryptodonta)
 * Subclass Lamellibranchia
 * Superorder Filibranchia (= Pteriomorpha)
 * Superorder Eulamellibranchia (= Heterodonta)
 * Order Palaeoheterodonta
 * Order Veneroida
 * Order Myoida
 * Subclass Anomalodesmata
 * Class Scaphopoda
 * Class Cephalopoda (= Siphonopoda)
 * Subclass Nautiloidea (= Tetrabranchiata)
 * Subclass Coleoidea (= Dibranchiata)
 * Order Sepioida
 * Order Teuthoida (= Decapoda)
 * Order Octopoda
 * Order Vampyromorpha

Phylum Phoronida

 * Phylum Phoronida

Phylum Ectoprocta (= Bryozoa)

 * Phylum Ectoprocta (= Bryozoa)
 * Class Phylactolaemata
 * Class Stenolaemata
 * Class Gymnolaemata
 * Order Ctenostomata
 * Order Cheilostomata

Phylum Brachiopoda

 * Phylum Brachiopoda
 * Class Inarticulata
 * Class Articulata

Phylum Echinodermata

 * Phylum Echinodermata
 * Class Crinoidea
 * Class Asteroidea
 * Order Platysterida
 * Order Paxillosida
 * Order Valvatida
 * Order Spinulosida
 * Order Forcipulatida
 * ”Sea daisies” (previously the class Concentricycloidea, but assigned by many authorities to the Spinulosida)
 * Class Ophiuroidea
 * Order Oegophiurida
 * Order Phrynophiurida
 * Order Ophiurida
 * Class Echinoidea
 * Subclass Cidaroidea
 * Subclass Euechinoidea
 * Infraclass Echinothurioidea
 * Infraclass Acroechinoidea
 * Cohort Diadematacea
 * Cohort Echinacea
 * Cohort Irregularia
 * Class Holothuroidea
 * Subclass Dendrochirotacea
 * Order Dactylochirotida
 * Order Dendrochirotida
 * Subclass Aspidochirotacea
 * Order Aspidochirotida
 * Order Elasipodida
 * Subclass Apodacea
 * Order Molpadida
 * Order Apodida

Phylum Chaetognatha

 * Phylum Chaetognatha
 * Order Phragmophora
 * Order Aphragmophora

Phylum Hemichordata

 * Phylum Hemichordata
 * Class Enteropneusta
 * Class Pterobranchia
 * Class Planctosphaeroidea

Phylum Chordata

 * Phylum Chordata
 * Subphylum Urochordata (= Tunicata)
 * Class Ascidiacea
 * Class Thaliacea
 * Class Appendicularia (= Larvacea)
 * Class Sorberacea
 * Subphylum Cephalochordata (= Acrania)
 * Subphylum Vertebrata
 * Class Myxini
 * Class Cephalaspidomorphi
 * Class Chondrichthyes
 * Class Osteichthyes
 * Class Amphibia
 * Class Reptiliomorpha (= Sauropsida)
 * Class Mammalia