# 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 Eubacteria, also known as Bacteria – Domain of microorganisms
* Kingdom Archaea, also known as Archaebacteria – Domain of single-celled organisms

## Eukaryotes (Eukaryota, or Eukarya)

* Kingdom Fungi – Biological kingdom, separate from plants and animals
* Kingdom Plantae – Kingdom of photosynthetic eukaryotes (= Metaphyta)
* Kingdom Protista – Eukaryotes other than animals, plants or fungi
      * Phylum Euglenida – Class of protozoans
      * Phylum Kinetoplastida – Flagellated protists belonging to the phylum Euglenozoa
      * Alveolata phyla – Superphylum of protists
            * Phylum Ciliophora – Taxon of protozoans with hair-like organelles called cilia
            * Phylum Apicomplexa – Phylum of parasitic alveolates
            * Phylum Dinoflagellata – Unicellular algae with two flagella
      * Phylum Stramenopila – Clade of eukaryotesPages displaying short descriptions of redirect targets
      * Phylum Rhizopoda – Cellular body type
      * Phylum Actinopoda – Cellular body type
      * Phylum Granuloreticulosa – Phylum of amoeboid protists
      * Phylum Diplomonadida – Group of mostly parasitic flagellates
      * Phylum Parabasilida – Group of flagellated protists
      * Phylum Cryptomonada – Group of algae and colorless flagellatesPages displaying short descriptions of redirect targets
      * Phylum Microspora – Taxon of autotrophic fungus-like protists
      * Phylum Ascetospora – A group of eukaryotes that are parasites of animals
      * Phylum Choanoflagellata – Group of eukaryotes considered the closest living relatives of animals
      * Phylum Chlorophyta – Phylum of green algae
      * Phylum Opalinida – Small group of peculiar heterokonts, family Opalinidae, order Slopalinida
      * Incertae sedis: Genus Stephanopogon – Genus of flagellate marine protozoan

### Kingdom Animalia (Metazoa)
#### Parazoa
##### Phylum Porifera

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

#### Mesozoa
##### Phylum Placozoa

* Phylum Placozoa
      * Trichoplax adhaerens

##### Phylum Monoblastozoa

* Phylum Monoblastozoa
      * Salinella

##### Phylum Rhombozoa

* Phylum Rhombozoa
      * Order Dicyemida
      * Order Heterocyemida

##### Phylum Orthonectida

* Phylum Orthonectida

#### Eumetazoa
##### Radiata
###### 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