Subsubspecies

[…]and any geographical sections of the whole which have been called by distinct names are, by definition, only subspecies, or even subsubspecies.

Source: wiktionary

Kinsey’s species of Cynips are considered to be only subspecies or subsubspecies by Goldschmidt (282).

Source: wiktionary

Cases may also be encountered where very distinct subspecies appear to have been further segregated into what might be equivalent to “subsubspecies.”

Source: wiktionary

Moreover, a species usually encompasses subordinate classification groups such as subspecies (or varieties), subsubspecies (or races), and strains, and these too are distinguished by particular, unique variations (Fig. 16.2).

Source: wiktionary