List of animal phyla

List of animal phyla is a list of the major groups of animals usually classified as a phylum. Modern sources have been used: the list is different from that of Linnaeus or Cuvier. A list of this type may be arranged alphabetically; equally it might be arranged according to evolutionary relationships. No list will be completely satisfactory. Authorities differ in what they consider a phylum, and in the actual name of the phylum. Despite this, there is agreement on most phyla. Most modern surveys include groups above the phylum, based on evidence of common descent.
Differences of opinion about evolutionary relationships have been reduced by the use of molecular evolution and molecular clock research. These make use of protein amino acid sequences, and whole genome DNA sequence analysis. These modern techniques have led to changes and renaming of many higher categories. Classification based on traditional comparative anatomy had errors which needed to be corrected. For example, the old phylum Coelenterata, which had stood for almost two hundred years, was split down into two separate phyla, the Cnidaria and the Ctenophora. 
The following list is based on evolutionary relationships:
Phyla.
Major groups in large text.
Reflections.
At least 21 phyla are exclusively aquatic, with several others in quasi-aquatic habitats on land. "None" are entirely terrestrial. This is testimony to the importance of water for life, and to the sea in particular. It is fairly certain that all phyla originated in the sea or, at any rate, in water. Most made their first showing in the Cambrian, or in the Ediacaran. Most of the soft-bodied phyla have left few fossils.
Phyla may be grouped according to evidence about their evolutionary relationships. The list above puts similar groups together.
This kind of megataxonomy is becoming more convincing as DNA sequence analysis proceeds through the phyla. Some entirely fossil groups are still placed where they are on anatomy and commonsense rather than hard molecular evidence. The trilobites are a good example. Their position in the Arthropoda is based on not much more than their bilateral symmetry and an exoskeleton. These groupings are discussed further in the references to this page.
Sortable table.
This table has the advantage of being sortable. The terminology differs in places from the above descriptions. Also, by listing living species only for most phyla, those with huge fossil records (like Bryozoa and Brachiopods) are lower in the order despite being important aquatic forms in the Palaeozoic era.
Groups formerly ranked as phyla.
This list is to help when you read older literature which may use out-of-date terms.