Phyciodes tharos, RIOCOLORADO

Pavulaan, Harry, 2023, Examination of the status of Phyciodes tharos distincta Bauer, 1975, confirming it as a valid subspecies., The Taxonomic Report of the International Lepidoptera Survey 11 (4), pp. 1-11 : 8

COMMENT ON P. THAROS RIOCOLORADO

Scott (1992) described Phyciodes tharos riocolorado (initially as Phyciodes tharos / morpheus riocolorado): “Adults…are characterized by having the same pattern of dark lines as typical Phyciodes tharos /morpheus tharos but the black borders are narrower, and the overall upperside color is more ochre-orange (less reddish-orange) than other tharos populations (adults vary little in upperside color)…This subspecies is not enormously different from ssp. tharos .” In agreeing with Scott’s latter point, a series of reared male specimens from Grand County, UT. in my possession, as well as images in iNaturalist from Utah, are essentially indistinguishable from reared nominotypical male tharos ( Fig. 7), by shade of orange and by extent of markings, and fall well within the range of variation of nominotypical tharos . Females in the Utah series differ from nom. tharos mainly by having less extensive and less heavy black infuscation on the basal half of the dorsal forewing ( Fig. 7), as Scott (1994) noted, which characterizes many tharos females. This gives riocolorado females a “paler” look, and fairly similar to distincta . Thus, I am inclined to view riocolorado as a weak subspecies based on a single female character (basal dorsal infuscation). A better set of character differences need to be identified, especially for the males [outside the scope of this paper].

Scott (1994) asserted: “This ssp. has blackish antenna clubs, whereas the clubs are orange on E. Colo. tharos, indicating that riocolorado derived from lower Colorado River (W Arizona /SE Calif.) stock rather than western Great Plains stock which has orange antennae.” [Western Great Plains orange-antenna populations are now deemed to be species-level Phyciodes orantain (Zhang, et. al., 2022)]. Due to extreme similarity to nominotypical tharos males ( Fig. 7), I contend that riocolorado is likely derived from nominotypical tharos stock, with females appearing more like distincta . Thus, riocolorado can be viewed as an intermediate population. Scott continued: “When I named riocolorado I described the wings are oranger, but actually the orange seems to be about the same tint as ssp. tharos but the wings appear paler because the black markings are much smaller, even on unf the black spots are smaller.” [See comments above, regarding dorsal differences in females.] Scott goes on to describe other minor differences from nom. tharos , mainly in the shape of the genitalia and differences in the larvae and pupae. I consider riocolorado a weak subspecies but propose no changes to nomenclature here.