Subphylum
In zoological nomenclature, a subphylum is a taxonomic rank below the rank of phylum.
The taxonomic rank of 'subdivision' in fungi and plant taxonomy is equivalent to 'subphylum' in zoological taxonomy.
Taxonomic rank
Subphylum is:
subordinate to the phylum
superordinate to the infraphylum.
Where convenient, subphyla in turn may be divided into infraphyla; in turn such an infraphylum also would be superordinate to any classes or superclasses in the hierarchy.
Examples
Not all fauna phyla are divided into subphyla. Those that are include:
Arthropoda: divided into subphyla Trilobitomorpha, Chelicerata, Myriapoda, Hexapoda and Crustacea,
Brachiopoda: divided into subphyla Linguliformea, Craniformea and Rhynchonelliformea,
Chordata: divided into Tunicata, Cephalochordata, and its largest subphylum Vertebrata.
Examples of infraphyla include the Mycetozoa and the Gnathostomata.