Isoperla peterzwicki, Stark & Sivec, 2008

Stark, Bill P. & Sivec, Ignac, 2008, New Stoneflies (Plecoptera) From Asia, Illiesia 4 (1), pp. 1-10 : 7-8

Isoperla peterzwicki sp. n.

( Figs. 22 -28)

Material examined. Holotype ♂ and paratype ♀ from Thailand, Doi Inthanon National Park , Bang Khun Klang, 1200 m, 26 January 1990, P. Chantaramongkol, H. Malicky ( PMSL).

Adult habitus. General color brown patterned with pale. Head with a dark brown transverse, arcuate band crossing posterior ocelli, and a wide longitudinal band extending from pale M-line through ocellar triangle ( Fig. 22 ); an additional area of brown pigment extends forward of M-line to near anterior margin of head. Pronotum with mesal and lateral pale bands; disc pale brown with scattered islands of darker pigment. Palpi, antennae, distal part of femur and proximal part of tibiae dark brown.

Male. Forewing length 12 mm. Abdominal terga unmodified; paraprocts weakly sclerotized, slightly curved inward and dorsad, and more or less triangular in outline ( Fig. 23 ). Abdominal sternum 8 bears a wide, slightly projecting, hairy vesicle ( Fig. 25 ). Aedeagal apex membranous, armed with a series of partially sclerotized irregular crenulations along dorsal margin ( Fig. 24 ).

Female. Forewing length 13 mm. Subgenital plate poorly developed; posterior margin of sternum 8 only slightly produced in middle third ( Fig. 25 ).

Egg. Oddly shaped with basic cylindrical form impressed by concave depressions on sides and ends giving a child’s toy drum appearance (Fig. 26). Anchor pancake-shaped (Fig. 27). Chorion impunctate but covered throughout with follicle cell impressions (Figs. 27-28). Micropyles minute (Fig. 28).

Etymology. The patronym honors Professor Dr. Peter Zwick, in recognition of his recent work with Asian species of genus Isoperla (Zwick & Surenkhorloo 2005) .

Diagnosis and Discussion. Not much is known of previously described Isoperla from the Oriental region, but Wu (1938) includes illustrations for a few species in his monograph of Chinese stoneflies. Unfortunately, the types for all these species are apparently destroyed, but none of the Wu figures show the combination of subgenital plate shape and male vesicle shape of this species, and no Isoperla species from Asia with eggs of this type are presently known.

Figures

Figs. 22-25. Isoperla peterzwicki. 22. Head and pronotum, 23. Male abdominal sterna 8-10, 24. Male aedeagus, lateral aspect, 25. Female abdominal sterna 8-10.