Paraleuctra malaisei, 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 : 88-89

Paraleuctra malaisei sp. n.

(Figs. 38, 39)

Material examined. ♂ holoptype, ♂ paratype, 1♀, REPUBLIC OF KOREA, Jirisan , Hamyang-gun, Macheon-Myeon, Samjeon-li, Alt. 700 m, 35°20.93'N 127°38.50'E, 11.IV.-8.V. 2004, Malaise trap on small stream,. Chungbuk, Sangchon-Myeon, Dungeon-li near Doma Pass, Alt. 750 m, 2.-26.V. 2006, 2 Malaise traps in forest on small stream , 1♀.

Adult habitus. A typical slender Paraleuctra of the occidentalis-group. FWL male, 2.7-2.8 mm, female, 3.1 mm.

Male. T9 caudally slightly raised. Flat hairy ventral lobe on S9 almost circular in ventral view (Fig. 38). S9 forms a subgenital plate with deep and wide Ushaped caudal notch. T10 with recessed antecosta and a median furrow that ends caudally in a deep bracket-shaped notch separating two lobes, each about 1/3 segment width, distally rounded. Epiproct a simple strongly upcurved sharp hook. Cercus slender, with dorsal bulge, tip distinctly emarginate, the rudimentary 2 nd segment located in the middle of a notch separating two unequal teeth (Fig. 38). The dorsal tooth is larger and directed dorso-caudad, the ventral tooth points ventrad. In caudal view, the inner edge of cercus appears straight, and both apical teeth point mediad.

In lateral view, the U-shaped base of the subanal probe is by transparency seen inside segment 9. The slender exposed part curves up regularly between the lobes of S9. The posterior face of the probe ends in a membraneous semicircular caudal projection and anteriorly in an elongate swelling extending further basad than the other structure (Fig. 38). In caudal view of the probe tip (Fig. 39), the dark lateral sclerites form a narrowly parabolic loop surrounding the rearward pointing membraneous part. The anterior membraneous part is rhomboid. The membraneous scaly parts at the probe tip are covered with numerous small downwardly pointing spicules.

Female. At present, the female cannot be distinguished from P. okamotoa (Claassen) (= gracilis Kawai, after Shimizu 2000), from Hokkaido and Sachalin. In both, sternite 9 is patterned in a similar way and ends in a broad, gently bilobed subgenital plate ( Zhiltzova 2003: fig. 876).

Diagnosis. Paraleuctra malaisei belongs to the occidentalis-species-group as defined by Stark & Kyzar (2001). By the slender but apically notched male cercus, the American P. occidentalis , P. jewetti , P. alta , and P. projecta are more similar to P. malaisei than the Asian members of the group which have only a medially bent nipple-like apex of male cercus ( Shimizu 2000, Zhiltzova 2003, Li et al. 2010). By the shape of the subanal probe (which is the copulatory organ) P. malaisei differs clearly from all American (see figures in Baumann et al. 1977, Baumann & Stark 2009) and Asian species ( Shimizu 2000, Li et al.2010). The two Asian mainland species of the group differ strongly. In Zhiltzova's (2003) excellent figures the apex of the subanal probe of P. okamotoa is concealed in lateral view and is therefore shown here (Figs. 40, 41).

Etymology. Named for René Malaise (1892-1978), dipterist and Swedish inventor of the efficient trap with which the present collections were made. René Malaise worked for years on the fauna of the Far East.