Squamellaria guppyanum is the closest relative of
Squamellaria kajewskii. Formerly described as
Hydnophytum, both species are now more likely to be assigned to the genus
Squamellaria on the basis of phylogenetic studies
. While Squamellaria kajewskii has an extremely symmetrical caudex, the same appears very irregular at first glance in S. guppyanum. The caudex is silvery green and has numerous elevations.