Monospecificity
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.