Isoperla asiatica Šámal, 1939

Judson, Sarah W. & Nelson, C. Riley, 2012, 3541, Zootaxa 3541, pp. 1-118 : 46-47

Isoperla asiatica Šámal, 1939

SYNONYMY

Isoperla asiatica Šámal, 1939

TYPE LOCALITY: Mongolia, Sogino , Tula .

DIAGNOSIS: The adult head is pale overall, with dark pigmentation surrounding the interocellar region which contains a pale oval spot ( Fig. 316). This pale central mark is broadly rounded in I. asiatica , whereas in I. potanini ( Fig. 345) and I. mongolica ( Fig. 336) it is pointed anteriorly and in othe r Isoperla it is more narrow. The mesoscutum has golden-yellow markings anteriorly ( Fig. 316), similar to I. kozlovi Zhiltzova, 1972 ( Fig. 326), I. mongolica , and K. nigricauda , but distinct from I. potanini which has uniformly dark mesoscutum ( Fig. 345). Males have poorly sclerotized paraprocts that are oriented dorsally and do not curve anteriorly over the 10th tergum. The vesicle on the 8th sternum is rounded and sessile ( Fig. 318), most similar to I. potanini which entirely lacks a lobe and is smooth along the segment 8 ( Fig. 347). Isoperla asiatica males can also be distinguished from I. potanini by cercal segments which posses only a single long hair per segment, in contrast to I. potanini cerci which have a whorl of long hairs on each segment. The female has a short, broadly rounded or truncate plate ( Fig. 319) which is indistinguishable from I. mongolica ( Fig. 339), but is distinct from the notched plate of I. potanini ( Fig. 348). Nymphs have a pale central ocellar mark ( Fig. 303) and color patterns reminiscent of the adult.

DISTRIBUTION—Global: East Palearctic— Regional: AOB, IDB^, POB*- Aimag: AR^, BU^, DO*, KhE*, KhG^, SE, TO, UB, ZA^.

DISCUSSION: In Mongolia, I. asiatica is most commonly found in large, low gradient streams. From our collections, this species appears to be restricted to the Selenge River basin ( Fig. 320), but is predicted to occur in the eastern Khentii region where it has been documented historically (Zwick and Surenkhorloo 2005).