Perlomyia

Perlomyia sp. Ko2

(Figs. 28–30, 33)

Rhopalopsole mahunkai Zwick, 1973 — Zwick 1973a: 163. (the single female was designated a paratype of P. mahunkai).

Literature data. Zwick (1973a), under Rhopalopsole mahunkai: (North Korea), Diamond Range, Manmul san (Kangwon Province, Kosŏng-gun, Kumgang Mts., singled along the way to Manmul-sang Rocks), N38°43’ E128°07’, 30.05.1970 (loc. Korea.68), leg. Sándor Mahunka, Henrik Steinmann: 1♀ (HNHM).

Diagnosis. Female: Sternum VII rectangular, without any modification, not fused to sternum VIII. Median sclerites on sternum VIII are well separated, bean-shaped and as long as the segment’s length; no additional sclerites on sternum VIII.

Description. Medium sized species, macropterous. Forewing length of the single female: 6.0 mm. Head dark brown with a few rugosities; antennae brown, palpi pale. Pronotum paler than head, a bit longer than wide, narrower than head; rugosities distinct. Meso- and metanotum brown, with longitudinally arranged dark brown patches; meso- and metathoracic basisterna with a pair of longitudinal dark stripes. Legs uniformly brown; wings hyaline, venation light brown. Pilosity generally short.

Female abdomen: Terga I–IX membranous, but with transverse row of four pigmented spots. Tergum X fully sclerotized. Sterna I–VI simple. Sternum VII rectangular, without any modification; not fused to sternum VIII. A thin, horseshoe-shaped spermathecal sclerite is visible after KOH-treatment. Median sclerites on sternum VIII are bean-shape, dark brown and well separated; their length is equal to segment’s length. Surface of the sclerites is smooth and bald. The segment bears no other sclerites besides the median sclerites, but the membrane is raised and winkled anteriorly and laterally to the sclerites; this condition is probably due to a sphermatophore that is now lost from the specimen. Sternum IX simple, sternum X medially connected. Paraproct and cercus simple.

Distribution and ecology. This species was caught at a single locality in the Kumgang Mts., East-central part of the Korean Peninsula, at the end of May (Fig. 33). Sympatric specimens were the holotype of Nemoura sahlbergi problematica Zwick, 1973a (nomen dubium, according to Zwick (2010)), females of further two Nemoura species, Alloperla picta Zwick, 1973a, and A. rostellata (Klapálek, 1923).

Affinities. This species is unique among the known female Perlomyia, by having two large, bean-shaped and well-separated median sclerites on sternum VIII. Slightly similar median sclerites occur on P. honshu Sivec & Stark, 2012a, but those are much smaller, and laterally surrounded by additional dark sclerites.