Pieris mihon Yakovlev, 2006 stat. nov.

Pieris euorientis mihon Yakovlev, 2006; Eversmannia 6: 17; TL: "W. Mongolia, Bayan-Ulegei aimak, 2100-2300 m" (original description)

Pieris ochsenheimeri tianshansis Tadokoro, Shinkawa & Wang 2014: Butterflies 65: 20; TL: East Tianshan Mts [S. Urumuqi, Xinjiang, China] syn. nov.

Description.

spring form: male (Fig. 9D, H): both wings whitish on both sides. Apical spot blackish, triangular, extending along veins to outer margin without merging or suffusion. All discal spots absent or only the 1st discal spot faintly expressed, outer spot absent or faint on the upperside. Outer edge of hindwing black powdered along vein tips. Female (Fig. 9E): both wings white on the upperside and a creamy yellow hue on the underside. All veins strongly brownish powdered but narrowly developed along veins without suffusion. The 1st, 2nd, and outer spots distinct on the upperside while faintly indicated on the underside, the 3rd spot absent or rather vague on the upperside, but mostly absent on the underside. Summer form: male (Fig. 9F): resembling the first generation but the apical spot merging as an apical band running from costa to vein CuA1. The 1st spot distinct while other spots mostly absent on the upperside; the 1st and 2nd spots present on the underside, while others absent. Female (Fig. 9G): resembling the first generation while veins less brownish powdered. All spots on the upperside rather strongly expressed, while the 3rd spot and outer spot absent on the underside.

Distribution.

West Mongolia (Bayan-Ulegei aimak), South Russia (Tanguura Mountains), West China (Xinjiang)

Phenology.

Bivoltine from May to August

Male genitalia.

(Fig. 5I) terminal part of tegumen without distinct convex; basal part of uncus slightly narrowed as terminal part of tegumen; uncus with moderately convex at its median part, apical half of uncus digitation.

Female genitalia.

(Fig. 6E) posterior apophysis short and relatively robust; inner distal of sterigma lobe shaped, almost contact in the center; inner basal of sterigma with steeply convex near the median part, smoothly connected at the basal margin; signum relatively short and slender, spindle shaped.

Note.

We noticed that specimens of this taxon previously recognized as P. euorientis by Eitschberger (1983) were published as a subspecies of P. euorientis (ssp. Pieris euorientis mihon) by Yakovlev (2006). Tadokoro et al. (2014) treated this taxon as P. ochsenheimeri tianshansis according to their phylogenetic results. However, it can be easily distinguished from P. euorientis, as the blackish apical spot is scattered and with a clear boundary without merging or suffusion (in P. euorientis grey and merging intra veins) and a mostly absent 1st discal spot (in P. euorientis mostly present but rather faint). After jointly observing the specimens of this study and a series of materials in Eitschberger (1983) and Tshikolovets (2009), we believe that the western population (populations around Tuva Republic and westwards) of the previously considered P. euorientis is P. mihon, while the eastern population (populations around Sayan Mountains and eastwards) is the real P. euorientis (Fig. 12). Although the molecular data of type specimens are lacking for phylogenetic analysis, this taxon can be morphologically distinguished from all similar species in the same regions. (e. g. the absence of all discal spot of males on the upperside). According to our phylogenetic results of Chinese specimens, this taxon was well defined as monophyletic and not clustering with P. ochsenheimeri . Combining the unique morphological characteristics of this taxon, until additional informative molecular evidence contradicts morphological results, we suggest that it should be treated as a distinct species, and therefore propose P. ochsenheimeri tianshansis as a new synonym for P. mihon .