A redefinition of Vikramus Denmark and Evans (Parasitiformes: Mesostigmata) with a complementary description of Vikramus argentinus (Guanilo and Moraes) comb. nov.

The genus Vikramus Denmark and Evans was originally established as a monotypic genus based on its type species, V. cordobus. However, its original description was not sufficiently detailed. In the present study, we provide a redefinition of this genus based on the examination of the holotype female of V. cordobus and detailed photos of the holotype and paratypes of Neoseiulus argentinus Guanilo and Moraes. The genus is recognized as valid based on a unique combination of diagnostic characters, including an elongated ventrianal shield, with its width at the level of seta ZV2 subequal to that at the level of the anal opening; small, rounded preanal solenostomes, relatively well separated and located closer to the bases of setae JV2; a simple, bell-shaped spermatheca, with a small, nodular atrium attached to the calyx by a very short neck, never forked at the juncture with the major duct; chelicera dentition; clubbed and strongly serrated dorsal setae and ventral seta JV5, except for j4, j5, j6, J2, and z5, which are smooth and sharply pointed. Examination of the type specimens revealed that the type species of this genus, V. cordobus, is conspecific with N. argentinus. Accordingly, Vikramus argentinus (Guanilo and Moraes) comb. nov. is recognized as the sole valid species of the genus, and a complementary description is provided. Moreover, the taxonomic status of Vikramus as a distinct valid genus is subsequently discussed and justified based on its unique combination of morphological characters and the polyphyletic nature of Neoseiulus sensu Chant and McMurtry. This study contributes to a clearer definition of generic boundaries within the family Phytoseiidae.