Monospecificity

This article is about taxonomy. For immunology, see Monospecific antibody.

In zoology, a monospecific genus is one containing only one known species. The word is of hybrid origin, with the prefix coming from Ancient Greek: μονο- (mono-) "single", and Latin: species, "kind" or "type".

Of the genera described in zoology, there are more monospecific genera than genera with any other individual number of species. Nevertheless, many genera originally considered monospecific, have been discovered to contain more than one species. Examples include Malapterurus the electric catfish and Loxodonta the African elephant. On the other hand, there are cases such as Pseudorinelepis where after an initial flurry of species descriptions a genus turns out to be monospecific.

Zoologists instead use the term "monotypic" when referring to a higher taxon that contains only one immediately subordinate taxon. For example, a family which contains a single genus is said to be monotypic, even if that genus comprises many species.

In botany, "monotypic" or "unispecific" are more commonly used instead of "monospecific" to refer to a taxon – at any rank – that includes only one species.