Isocapnia apicispina Chen & Du, 2017

Chen, Zhi-Teng & Du, Yu-Zhou, 2017, New species and a new record of Capniidae (Plecoptera) from Xinjiang Uygur Autonomous Region of northwestern China, Zootaxa 4311 (1), pp. 122-128 : 124

Isocapnia apicispina Chen & Du , sp. nov.

Figs. 7–15 .

Male. Body length 10.6 mm. Forewings length 9.7 mm, hindwings length 8.7 mm. Body generally dark brown. Head rounded, nearly as wide as pronotum; three ocelli pale, compound eyes dark ( Fig. 7 ). Pronotum quadrate, corners obtuse. Wings macropterous, subhyaline with brown veins; forewings with four costal cross veins before end of Sc; hindwings with four costal cross veins before end of Sc; anal field of hindwings small and folded with three veins. Tergal antecosta interrupted on terga 1–5 and 10, complete on terga 6–9 ( Fig. 7 ). Legs brown to dark brown. Cerci slender and brown, each segment parallel-sided with long distal hairs ( Fig. 7 ).

Male abdomen: Tergum 9 strongly concave and sclerotized at anterior and posterior margins ( Fig. 8 ). Tergum 10 cleft with sclerotized margins. From dorsal aspect, basal sclerite trapezoidal and slightly depressed posteriorly. Main epiproct sclerite gradually tapered from base to the triangular apex from dorsal view ( Fig. 8 ). In lateral view, main epiproct sclerite upcurved and gradually constricted with a ventroapical spine, bearing sparse setae; dorsal surface of apical main epiproct sclerite truncated, lateral margins with small sensilla ( Figs. 9, 11 ). Sternum 9 with a fusiform, setose vesicle, with a thin basal stem, length ⅓ of subgenital plate ( Fig. 10 ). Subgenital plate broad basally and sharp apically, strongly sclerotized anterolaterally; paraprocts curved, anterolateral margins obtuse ( Fig. 10 ).

Female. Body length 14.5–15.0 mm. Forewings length 10–10.5 mm, hindwings length 9.5–10.0 mm. General color similar to male; terga 2–8 with median membranous area ( Fig. 12 ). Sternum 8 with a medially constricted subgenital plate butterfly-like shaped, the plate anteriorly connected with dark anterior sclerites; the lateral sclerites subtriangular, with punctuate surface and darkly sclerotized anterior angles ( Fig. 13 ).

Type material. Holotype: male, China: Xinjiang Uygur Autonomous Region, Fuyun County, Riverside Park, Eerqisi River , 793m, 46.9865 N, 89.5247 E, 29 April, 2017, Hai-Yang Xue ( ICYZU) . Paratypes: 1 male and 6 females, same locality and data as holotype ( ICYZU) .

Etymology. The specific epithet refers to the apical spine of epiproct.

Remarks. Male paratype of the new species is strongly micropterous (forewings length 0.75 mm, hindwings length 0.5 mm) and its main epiproct sclerite is more curved, indicating the presence of wing polymorphism in this species ( Figs. 14–15 ). The new species seems most similar to I. arcuata Zhiltzova, 1975 (in: Zhiltzova et al. 1975, Zenger & Baumann 2004) from Russia, but can be distinguished by its dorsal apex of main epiproct sclerite truncated with denticulate lateral margins, by having a ventroapical spine on epiproct, and by the sclerite of sternum 8 in the shape of a butterfly. In I. arcuata , male main epiproct sclerite is much longer with a rounded tip; shape of sclerite on sternum 8 in females also differs from that in the new species (see figs. 1038–1040 in Teslenko & Zhiltzova 2009).

Figures

FIGURES 7 – 15. Isocapnia apicispina, sp. nov. 7. Male holotype, habitus, dorsal view; 8. Male holotype, terminalia, dorsal view; 9. Male holotype, terminalia, lateral view; 10. Male holotype, terminalia, ventral view; 11. Apex of male holotype, epiproct, dorsolateral view; 12. Female habitus, dorsal view; 13. Female terminalia, ventral view; 14. Male paratype, habitus, dorsal view; 15. Male paratype, terminalia, dorsolateral view.