Sweltsa zhiltzovae, Zwick, 2010

Zwick, Peter, 2010, New Species And New Records Of Plecoptera From Korea And The Russian Far East, Illiesia 6 (9), pp. 75-97 : 94-95

Sweltsa zhiltzovae sp. n.

( Figs. 52-56 )

Material examined. ♂ holotype, 2♂ paratypes, REPUBLIC OF KOREA, Chungbuk, SangchonMyeon, Dungeon-li near Doma Pass , Alt. 750 m, 2.- 26.V. 2006, 2 Malaise traps in forest on small stream. Adult habitus. A pale yellowish species, FWL 8.7 mm. The head has a wide chocolate brown angled mark connecting the ocelli ( Fig. 52 ). The area between this mark and the eyes is white and paler than the yellowish rest of the head. Pronotum , antennae, legs, and cerci are unicolorous. Meso- und metathorax have the usual narrow U-shaped mark, and a narrow brown line along the pleural suture. On the abdomen, T1 has a dark antecosta and a narrow brown longitudinal mark in the middle. Tergites 2-7 each have a wider brown longitudinal mark. Each is much wider in front than behind. Together they form a brown dorsal band with serrate edges.

Male. Middle part of antecosta 9 sclerotized but flat, separating two steeply rising back-curved fleshy cones ( Figs. 53, 54 ). Caudal margin of T9 triangularly excised, base of epiproct partly exposed. T10 completely divided into simple hemitergites by the large epiproct rising from a deep cowl ( Fig. 55 ). The scooped front part is laterally articulated and from this point on forms a basal rod in the bottom of the cowl. By transparency, its upcurved caudal end appears as a dark V-shaped mark in the base of the forward-bent part of the epiproct. The remarkably large and wide base of this part occupies about 1/3 of the length. The anterior 2/3 have in dorsal view the shape of a straight finger. In side view appears a strong triangular extension of the ventral contour line ( Fig. 56 ). The finger widens gently towards the rounded apex. The dorsal contour of the epiproct is indistinctly concave, almost straight. Between the hemitergites the lateral edges of the epiproct cowl are strengthened by distinct slender paragenital sclerites. No penial armature noticed.

Female. Not known.

Diagnosis. The pattern of the new species is distinctive. In case of doubt, the strong cones on T9, the acutely triangular ventral extension, and the wide and large base of the epiproct identify it immediately. Sweltsa lepnevae Zhiltzova from Primorje seems to be most similar but differs in pattern ( Teslenko & Zhiltzova 2009), females were available for comparison. Their head mark is only about half as wide, the distal 2/3 of antennae are dark brown, and there is a narrow dark margin along the front and sides of the pronotum. Males of S. lepnevae (from the description) have lower cones on T9, the epiproct has a narrow base and in side view no ventral entension. Its tip is slightly sinuous but essentially downcurved.

Etymology. The species is named in honour of Lidija Andrejevna Zhiltzova (St. Petersburg), my much admired colleague and dear friend, in recognition of her outstanding contributions to the knowledge of stoneflies, in particular of Asia.

Figures

Figures 52-56. Sweltsa zhiltzovae, ♂ holotype. 52, head, dorsal; 53, abdominal tip, lateral; 54, the same,. dorsal; 55, dorsal view of epiproct and its cowl; 56, distal part of epiproct in side view. Not to scale.