Diagnostic features
Segments are brown-purple and tuberculate. Conspicuously hairy areoles occur alongside cylindrical central spines about 3–4 mm long in the material described. The flower develops at the segment apex. This combination distinguishes the plant from species with less hairy areoles and a similar cylindrical habit. [Las Peñas and Bernardello 2021, Table 2]
The microscopic epidermal papillae are straight, with a striated base and smooth tip. The rest of the cuticle surface has deep, parallel striations. In the comparative paper, this regularity was among the distinguishing traits of P. gonjianii. [Faigón et al. 2011]
Restricted range and cytotype
The 2021 account describes the species as endemic to San Juan. Voucher material was linked to herbarium specimens and collection data. In the chloroplast tree it belonged to the group with P. megliolii and P. tuberosus, within a larger lineage including P. fischeri. [Las Peñas and Bernardello 2021]
Direct chromosome examination yielded 2n = 44. The table gave no DNA content measurement for this taxon. The tetraploid complement is therefore a cytological result for the material studied, not a calculation from genome mass. [Las Peñas and Bernardello 2021, Table 1]