Perlomyia ainu Sivec & Stark 2012, sp. n.

Perlomyia ainu sp. n.

(Figs. 1-3)

Material examined. Holotype ♂, Japan, Iwate Prefecture, Hienuki River, 16 km above Hayachine Dam, 3 May 2002, C.D. Kerst (PMSL).

Male. Forewing length 5 mm. General color dark brown to black. Epiproct long and slender, forming a narrow triangular structure in dorsal aspect (Fig. 1), and shaped like a raptorial beak in lateral aspect (Fig. 3). Tergum 9 broadly excavated on posterior margin; small knobs absent from tergum 10, but posterolateral margins developed into low wide mounds. Tergum 8 with small, erect median lobe truncate on posterior margin and tergum 6 with a minute posteromedian lobe. Cerci bear a small posteromedian spine in lateral aspect (Fig. 3). Paraprocts fused into a broad, thick process; lateral aspect of paraprocts wide at base and tapered to form a sagittate structure in ventral aspect (Fig. 2). Apex of sternum 9 curved strongly dorsad (Fig. 3); vesicle wide apically and tapered to base (Fig. 2).

Female. Unknown.

Larva. Unknown.

Etymology. The species name, used as a noun in apposition, honors the early Ainu culture once known from the area of the type locality.

Diagnosis. This species is one of at least four Japanese species without the distinctive pair of small knobs found on P. parva and several other members of the genus (Kawai 1967; Nelson & Hanson 1973); we are uncertain about the presence of these structures on P. gifuensis. This new species is easily distinguished from other Japanese species by the presence of a truncate lobe on male tergum 8 and by the small apical spine on the male cerci. Perlomyia kersti, described below, is the only other Japanese species known to have a male tergal lobe and in that species the dorsal lobe is located on tergum 9. At least two other Asian Perlomyia, P. levanidovae (Zhiltzova 1975) and P. smithae Nelson & Hanson 1973, lack knobs on male tergum 10, but these species also lack dorsal lobes on segment 8.