mackenziana Hammer, 1953: 50. Proisotoma.

Holotype: 1 (slide, mounted together with 4 specimens of two species of Onychiuridae) Canada. [Northwest Territories], Reindeer St[ation], 164, [9–18.vi.]1948, [on the bank of the Mackenzie river in wet recently deposited ooze with a little dead leaves and sparse moss],

M. Hammer (CNC 165117). Christiansen & Bellinger (1980–1981: 572) considered that “this specimen is immature and probably does not belong in the genus Proisotoma ”. Listed as Isotoma mackenziana (Hammer, 1953) by Fjellberg (2003: 96).