Capnia, Chen & Song, 2019

Chen, Zhi-Teng & Song, Liang-Dong, 2019, A new winter stonefly (Plecoptera: Capniidae) from Shaanxi Province of China, Zootaxa 4629 (2), pp. 237-246 : 237-238

Capnia s.l. bilobata sp. nov.

Figs. 2–10.

Male (Figs. 2–7). Body length ca. 6.5 mm. Forewings length 8.0 mm, hindwings length 6.5 mm. Body generally dark brown, basal four abdominal segments pale brown. Head rounded and completely dark, wider than pronotum. Pronotum laterally fringed with short hairs, with six anterior and anterolateral angles; anterior and posterior sutures of pronotum distinct; posterior of pronotum extended with two quadrate lobes. Wings macropterous; forewings with irregular pale patterns mostly on apical half; RA vein slightly curved at its divergence with RP; hind wings folded with four anal veins.

Ventral sclerites of thorax (Fig. 4). Prothorax: presternum oval, unfused with the sub-trapezoidal basisternum; precoxal bridge kidney-shaped, fused with basisternum; furcasternum rounded, fused with both basisternum and the slender, curved postcoxal bridge; postfurcasternum large, elliptical, divided, not fused with furcasternum. Mesothorax: spinasternum narrow, fused medially, not fused with prothoracic postfurcasternum but fused laterally with the large basisternum; presternum median-sized, elliptical, not fused with basisternum; furcasternum subtriangular, completely fused with basisternum, the furcasternal arms and the furcasternal pit; postfurcasternum divided into two lateral, subtriangular parts by the furcasternal pit, the parts are not fused with other sclerites; katepisternum subdivided from basisternum, but connected with the ventrally elongated trochantin. Metathorax: presternum subtriangular, not fused with the large basisternum; spinasterum small, razor-shaped and fused with basisternum; furcasternum elongated and fused with basisternum, laterally projecting backwards but not fused with abdominal sternum 1; katepisternum subdivided from basisterum but connected with the ventrally elongated trochantin.

Male abdomen (Figs. 5–7). Abdominal pigmentation dark brown; terga 1–4 pale brown, with interrupted, sclerotized anterior margins. Tergum 7 with two lateral patches of long hairs. Tergum 8 also with two lateral patches of much longer hairs; posterior half of tergum 8 membranous, somewhat wrinkled and extended backwards, with dense tiny spines. Posteromedial margin of tergum 9 with a falciform, bilobed projection, each lobe laterally covered with long hairs; in lateral aspect, the projection straight. A broad membranous area presents from posterior margin of tergum 9 to median area of the divided tergum 10, with dense rugosity. Main epiproct sclerite ca. 0.5 mm in length, broad at base, constricted at the vertical section, rounded dorsobasally, then gradually tapering to a sharp apex, marginated with short hairs; basal half of the main epiproct sclerite dark and smooth, apical half pale brown, spinulose, and hollow; from lateral aspect, the main epiproct sclerite constricted at the corner and the apex; the median fusion line depressed on basal half of the main epiproct sclerite; basal sclerite large; laterobasal sclerites medium sized and subtriangular, tightly fused with each other. The vesicle large oval and covered with dense setae, settled on the stripe-like sternum 9 base that is fused with tergum 9 at anterolateral portions. Subgenital plate large and tongue-shaped, divided from other sclerites. Paraprocts fusiform, apices with slender sclerites; fusion plate thin and elongated. Cercus slender with long apical bristles, distal portion of each segment enlarged; left and right cercus each with 16 and 15 segments, respectively.

Female ( Figs. 8 , 9). Body length ca. 8.5 mm. Forewings length ca. 9.0 mm, hindwings length ca. 8.0 mm. Pronotum subquadrate with obtuse corners. Terga 1–3 pale brown; terga 1–8 with a longitudinal, spinulose, membranous median area. Tergum 9 anteriorly with two small membranous area connected with the previous longitudinal membranous area. Subgenital plate originated from anterior margin of sternum 8, near hemi-elliptical; indistinct sclerites present anterior and lateral to the subgenital plate, the anterior ones fused with the subgenital plate, while the lateral ones weakly fused; a separated fusiform sclerite present beneath the subgenital plate, belonging to the genital opening. Left and right cercus each with 18 and 19 segments, respectively.

Type material. Holotype male, China: Shaanxi Province, Xi’an City, Qinling Mountain Range, Taiping National Forest Park , near a waterfall (Fig. 10), 1500 m, 31 March 2019, Leg. Liang-Dong Song . Paratype: 1 female, same locality and data as holotype .

Etymology. The specific epithet refers to the bilobed projection on male tergum 9.

Diagnosis. The new species belongs to the Capnia s.l. cordata group sensu Zhiltzova 2001 ( Muranyi et al. 2014). The male differs from other species of the group by the distinct, bilobed projection of tergum 9, and in details of the main epiproct sclerite (Figs. 5, 6). The female can be distinguished from most other species of the group by the relatively wide apex of the subgenital plate (Fig. 9).

Figures

FIGURE 8. Capnia s.l. bilobata sp. nov., Female paratype. A. Female habitus, dorsal view; B. Female head and pronotum, dorsal view; C. Female thoracic sclerites, ventral view.