List of animal classes explained

See also: List of bilateral animal orders. The following is a list of the classes in each phylum of the kingdom Animalia. There are 107 classes of animals in 33 phyla in this list. However, different sources give different numbers of classes and phyla. For example, Protura, Diplura, and Collembola are often considered to be the three orders in the class Entognatha. This list should by no means be considered complete and authoritative and should be used carefully.

Acanthocephala (thorny-headed worms)

• Archiacanthocephala
• Eoacanthocephala
• Palaeacanthocephala (ancient thornheads)
• Polyacanthocephala

Acoelomorpha (simple soft-bodied flatworms)

• Acoela
• Nemertodermatida

Annelida (segmented worms)

• Clitellata (earthworms)
• Polychaeta (bristle worms)
• Sipuncula (peanut worms)

Arthropoda (arthropods: insects, crustaceans, arachnids, centipedes, and millipedes)

See also: List of arthropod orders.

Chelicerata^[1]

• Arachnida (spiders, scorpions, and kin)
• Xiphosura (horseshoe crabs)
• Pycnogonida (sea spiders)

Crustacea^[2]

• Branchiopoda (fairy shrimp, tadpole shrimp, water fleas, and clam shrimp)^[3]
• Cephalocarida (horseshoe shrimp)^[4]
• Pentastomida (tongue worms)
• Branchiura (fish lice)
• Mystacocarida
• Copepoda
• Ostracoda (seed shrimp)^[5]
• Malacostraca (crabs, lobsters, crayfish, krill, various shrimp, woodlice, and kin)^[6]

Notes and References

1. Web site: Integrated Taxonomic Information System. ITIS Standard Report Page: Chelicerata. www.itis.gov.
2. Web site: Integrated Taxonomic Information System. ITIS Standard Report Page: Crustacea. www.itis.gov.
3. Web site: Regents of the University of California. Introduction to Brachiopoda. www.ucmp.berkeley.edu.
4. Web site: Archived copy . 2014-10-03 . https://web.archive.org/web/20141006123826/https://www.uni-ulm.de/fileadmin/website_uni_ulm/nawi.biodok/publikationen/2011_Olesen_etal_Cephalocarida-k.pdf . 2014-10-06 . dead .
5. Web site: Archived copy . 2014-10-03 . 2013-05-12 . https://web.archive.org/web/20130512091254/http://atiniui.nhm.org/pdfs/3839/3839.pdf . dead .
6. Web site: ITIS Standard Report Page: Hexapoda. www.itis.gov. Integrated Taxonomic Information System.
7. Web site: ITIS Standard Report Page: Myriapoda. www.itis.gov. Integrated Taxonomic Information System.
8. Tessler. Michael. Neumann. Johannes S.. Kamm. Kai. Osigus. Hans-Jürgen. Eshel. Gil. Narechania. Apurva. Burns. John A.. DeSalle. Rob. Schierwater. Bernd. Phylogenomics and the first higher taxonomy of Placozoa, an ancient and enigmatic animal phylum. Frontiers in Ecology and Evolution. 2022-12-08. 10. 10.3389/fevo.2022.1016357. free.
9. Web site: Conlan. Kathleen E.. Bousfield. Edward. Malacostracan | crustacean|url=https://www.britannica.com/animal/malacostracan|website=www.britannica.com}}
   • Thecostraca (barnacles)
   • Remipedia

   Hexapoda^[6]

   • Entognatha (coneheads, two-pronged bristletails and springtails)
   • Insecta (insects)

   Myriapoda^[7]

   • Chilopoda (centipedes)
   • Diplopoda (millipedes)
   • Pauropoda
   • Symphyla (pseudocentipedes)

   Brachiopoda ("lamp shells")

   • Lingulata
   • Craniata
   • Rhynchonellata

   Bryozoa (moss animals)

   • Gymnolaemata
   • Phylactolaemata
   • Stenolaemata

   Chaetognatha (arrow worms)

   • Sagittoidea

   Chordata (vertebrates, tunicates, and lancelets)

   See also: List of chordate orders.

   Cephalochordata

   • Leptocardii (lancelet)

   Tunicata

   • Appendicularia (larvaceans)
   • Ascidiacea (sea squirts, paraphyletic with respect to Thaliacea)
   • Thaliacea (salps, pyrosomes, and doliolids)

   Vertebrata

   Agnatha

   Cyclostomata

   • Myxini (hagfish)
   • Petromyzontida (lamprey)

   Gnathostomata

   • Chondrichthyes (cartilaginous fish: chimeras, sharks and rays)
   • Osteichthyes
     • Actinopterygii (ray-finned fish, which includes most familiar bony fish)
     • Sarcopterygii
       • Actinistia (coelacanths)
       • Dipnoi (lungfish)
       • Tetrapoda
         • Amphibia (amphibians)
         • Amniota
           • Mammalia (mammals)
           • Aves (birds)
           • Reptilia (reptiles, paraphyletic with respect to Aves)

   Cnidaria (marine stinging animals)

   • Octocorallia
   • Hexacorallia
   • Ceriantharia
   • Cubozoa (box jellyfish)
   • Hydrozoa (hydroids)
   • Myxozoa (marine parasites)
   • Scyphozoa (true jellyfish)
   • Staurozoa (stalked jellyfish)
   • Polypodiozoa (marine parasites)

   Cycliophora (tiny marine animals)

   • Eucycliophora

   Dicyemida (rhombozoa)

   • Dicyemida

   Echinodermata (starfish, sea urchins, sand dollars, sea lilies, and others)

   See also: List of echinodermata orders.

   Crinozoa

   • Crinoidea (sea lilies and feather stars)

   Asterozoa

   • Asteroidea (star fish)
   • Ophiuroidea (brittle stars)

   Echinozoa

   • Echinoidea (sea urchins)
   • Holothuroidea (sea cucumbers)

   Entoprocta

   • Entoprocta

   Gastrotricha (hairybacks)

   • Gastrotricha

   Gnathostomulida (jaw worms)

   • Gnathostomulida
   • Enteropneusta (acorn worms)
   • Pterobranchia

   Kinorhyncha (mud dragons)

   • Allomalorhagida
   • Cyclorhagida

   Loricifera

   • Loricifera

   Mollusca (mollusks)

   • Aplacophora
   • Bivalvia (clams, mussels, scallops, and kin)
   • Cephalopoda (octopuses, squids and cuttlefish)
   • Gastropoda (snails and slugs)
   • Monoplacophora
   • Polyplacophora (chitons, or sea cradles)
   • Scaphopoda (tusk shells)

   Micrognathozoa

   • Micrognathozoa

   Nematoda (roundworms)

   • Chromadorea
   • Enoplea
   • Secernentea

   Nematomorpha (horsehair worms)

   • Gordioidea
   • Nectonematoida

   Nemertea (ribbon worms)

   • Anopla
   • Enopla

   Onychophora (velvet worms)

   • Onychophora

   Orthonectida

   • Orthonectida

   Placozoa

   • Polyplacotomia^[8]
   • Uniplacotomia

   Platyhelminthes (flatworms)

   • Cestoda (tapeworms and relatives)
   • Monogenea
   • Trematoda (flukes)
   • Turbellaria (e.g. Dugesia)

   Porifera (sponges)

   • Calcarea (calcareous sponges)
   • Demospongiae
   • Hexactinellida (glass sponges)
   • Homoscleromorpha

   Priapulida (priapulid worms)

   • Halicryptomorpha
   • Priapulimorpha
   • Seticoronaria

   Rotifera (rotifers)

   • Bdelloidea
   • Monogononta
   • Seisonidea

   Tardigrada (tardigrades, water bears, or moss piglets)

   • Eutardigrada
   • Heterotardigrada

   Xenoturbellida

   • Xenoturbellida

   References

   .