In zoological nomenclature, a syntype is any of two or more specimens listed in a species description where a holotype was not designated, a practice which was common historically. Those syntypes which have not been replaced are still considered name-bearing types. Historically, syntypes were often explicitly designated as such, and under the present International Code of Zoological Nomenclature this is a requirement in order for the designation to be valid, but modern attempts to publish species description based on syntypes are generally frowned upon by practicing taxonomists.

For species originally described from a set of syntypes, most of the existing syntypes are gradually being replaced by lectotypes. A lectotype is the single specimen selected from among the syntypes to serve as the only name-bearing type specimen, and is formally designated as such. Having a single name-bearing type reduces the potential for confusion, especially considering that it is not uncommon for a series of syntypes to contain specimens of more than one species.

The additional specimens from the original set of syntypes, after a lectotype has been designated from among them, are reduced to the status of paralectotype. They are no longer name-bearing types, though if the lectotype is lost or destroyed, it is generally preferrable to use a conspecific paralectotype as a replacement.