Mesonemoura zwicki, Li, Weihai, Cui, Jianxin & Yang, Ding, 2017

Li, Weihai, Cui, Jianxin & Yang, Ding, 2017, Three new species of Mesonemoura (Plecoptera: Nemouridae) from China, Zootaxa 4272 (2), pp. 276-284 : 280-282

Mesonemoura zwicki sp. nov.

( Figs. 3 )

Diagnosis. This species is characterized by the male tergum IX being produced into an asymmetrical, small, median protuberance at posterior margin fringed with 14–16 dark spines ( Fig. 3 a) and by the flagellum of the epiproct being gently curved in dorsal and lateral views, apical third constricted in dorsal view ( Figs. 3 a, 3e).

Adult. Male forewing length 10.2–10.3 mm. Head brown, compound eyes black, antennae brownish. Thorax dark brown; legs brownish but basal part of femora paler; wing membranes subhyaline, veins brownish. Abdomen brown terminal segments darker; hairs on abdomen mostly pale.

Male terminalia. Tergum IX moderately sclerotized, posterior margin produced into an asymmetric median protuberance fringed with ca. 14–16 dark spines, left portion being narrow and nearly triangular which is prominent both in dorsal and lateral views whereas the right portion being wide but much short ( Figs. 3 a & 3c). Hypoproct of sternum IX wide and trapezoidal basally, distinctly tapering medially toward upcurved, triangular tip, vesicle claviform, basal stalk darkly sclerotized and constricted, apex rounded, ventral surface most membranous ( Fig. 3 b). Tergum X sclerotized, with a membranous slit along the median concavity below epiproct, each anterolateral margin bearing several spinules ( Fig. 3 a). Cercus slightly sclerotized, longer than wide, slightly incurved subapically, in lateral view triangular ( Figs. 3 a–3c). Epiproct medially slightly constricted and moderately swollen subapically. Dorsal sclerite with sclerotized, thin and medially interrupted basal transverse sclerite, divergent in two thin lateral bands; apex bearing a gently left-curved flagellum, apical third constricted in dorsal view, the right side narrowly sclerotized, in lateral view the curve being slighter and membranous ( Figs. 3 d & 3e). Paraprocts tri-lobed and very similar to the above species, except the apical projection of median lobe much shorter, ca. as long as width ( Fig. 3 f).

Female. Unknown.

Type Material. Holotype: male ( HIST), China: Guizhou Province, Zunyi, Xishui County, Sancha River , 2012. III. 30, W.H. Li & W.F. Shi . Paratype, 1 male ( HIST), same data as holotype .

Distribution. China (Guizhou Province).

Etymology. The epithet honors Dr. Peter Zwick for his remarkable contributions to stonefly research.

Remarks. The new species is similar to M. flagellata ( Wu, 1935) from Jiangxi Province of southeastern China and M. sinistracurva Du & Wang, 2015 from Zhejiang Province of eastern China in having similar median protuberance at posterior margin of tergum IX, but M. zwicki may be easily separated from these two species by the presence of the gently curved flagellum of the epiproct and the by the thin, medially interrupted basal transverse sclerite of the epiproct. Additionally, the mid-posterior protuberance of tergum 9 in the new species is prominent both in dorsal and lateral views, whereas that of M. flagellata is indistinct in lateral view, trilobed and nearly symmetrical in dorsal view (figs. 36–37, Wu 1935) and that of M. sinistracurva indistinctly produced in dorsal view (figs. 13–15, Du et al. 2015).

Figures

FIGURE 3. Mesonemoura zwicki sp. n. a – f, male. a. Terminalia, dorsal view; b. Terminalia, ventral view; c. Terminalia, lateral view; d. Epiproct, dorsal view. e. Epiproct, lateral view; f. Paraproct, caudal view.