Filchneria songi Chen, 2019

Chen, Zhi-Teng, 2019, A new species and a new record of Perlodidae (Plecoptera) from China, Zootaxa 4623 (1), pp. 189-200 : 189-193

Filchneria songi Chen , sp. nov.

Figs. 1 –8.

Adult habitus ( Figs. 1 , 8B). Body dorsally dark, ventrally pale. Head mostly dark brown, with pale patterns.

Triocellate, anterior ocellus much smaller than posterior ones; a pale oval spot present between posterior ocelli. Antenna dark brown and slender, subequal in length to the abdomen. Pronotum subquadrate, corners obtuse, generally dark brown except for the irregular, pale median stripe. Meso- and metanota mostly dark brown; mesothoracic furcasterum branches reaching anterior of the furcal pits. Macropterous, wings exceed abdominal tip; wings pale brown, veins brown. Legs generally dark brown, joints pale. Abdominal terga generally dark; segments 1–4 divided into distinct terga and sterna; sterna mostly pale, with dark lateral stripes and spots. Cerci slender, subequal in length to the abdomen, generally brown, each segment with apical bristles.

Male ( Figs. 1A , 2 , 4, 5). Body length ca. 12.0 mm; forewing length ca. 11.0 mm, hindwing length 9.0 mm. In the forewing, the venation includes an irregular, complex net near the apex; four crossveins present between C and Sc; RP with six apical branches; anal are with five branches. In the hind wing, the apical net simpler than in the forewing; RP with four apical branches; anal area large, with 10 anal branches.

Abdominal tergum 7 with two posterior swellings which are covered by long hairs. Tergum 8 with an oval, membranous median area bearing short bristles; posterior margin with two conspicuous swellings which are covered by small sensilla basiconica. Tergum 9 mostly covered by tergum 8, posteromedially depressed; posterior margin slightly thickened, without conspicuous swellings or sensilla basiconica. Tergum 10 complete, paler than anterior terga, anteriorly with a dark spot located in the middle of a broad membranous area; posterior half of tergum 10 moderately elevated; each side of posterior margin with a patch of short, stout spines. Paraprocts mostly covered by tergum 10, generally pale, rugose from caudal view; the eversible paraproct lobe near conical, apex rounded, basally constricted, without obvious scales or spinules. The partially everted aedeagus membranous, apically with a large, complex lobe, basally with two rounded, lateral extensions.

Female ( Figs. 1B , 3, 6). Body length ca. 15.0 mm, color pattern generally similar to male. Subgenital plate originating from posterior of sternum 8, covering one-fourth of sternum 9. The subgenital plate broad and bilobed, posterior half weakly sclerotized and covered by short bristles; each lobe short and broad, apex truncate. Two subtriangular sclerites present anterior to the subgenital plate. Sternum 9 with two elliptical lateral spots, weakly sclerotized posteromedially.

Egg (Fig. 7). Trilateral, with three longitudinal ridges. Each side of the egg with a transverse ridge close to the posterior pole. Collar short, cylindrical. Anchor mushroom-shaped, completely rounded from view of the anchor pole, surface covered with tiny granules. A row of 2–3 obscure micropyles present near the transverse ridge on each side. Chorion surface rough with irregular, small tubercles.

Type material. Holotype: male, China: Shaanxi Province, Xi’an City, Qinling Mountain Range, Taiping National Forest Park , Taipingyu River (Fig. 8A), 33.9077 N, 108. 6513 E, 1200 m, 7 April 2019, leg. Liang-Dong Song (ICJUST) . Paratypes: 2 females, same locality and data as holotype ; 1 male and five females, same locality, 28 April 2019, leg. Zhi-Teng Chen & Liang-Dong Song (ICJUST) .

Etymology. The species is named for Mr. Liang-Dong Song who collected and generously provided the specimens.

Remarks. Navas’ (1936) species, F. furcifera described from a female holotype from Mt. Tianshan, Xinjiang, an autonomous territory in northwestern China was considered unrecognizable by Teslenko et al. (2010) because of the relatively inadequate original description. When compared with the original illustration of the female of F. furcifera , the posterior notch of female subgenital plate in F. songi is not so deep and triangular as in F. furcifera ; the lateral lobes of subgenital plate of F. furcifera are much slender than F. songi (see fig. 3 in Navas 1936). Additionally, considering the wide geographical separation between Mt. Tianshan and the Qingling Mountains by several large mountain ranges and the Yellow River, F. songi is less likely to be conspecific with F. furcifera . The bilobed female subgenital plate of F. songi distinguishes it from the truncate subgenital plate with two small lateral lobes in F. tau (see fig. 20 in Klapálek 1912). When compared with F. heteroptera , F. songi can be distinguished by the posteriorly depressed tergum 9, the median spot on the much-elevated tergum 10, and the undeveloped paraprocts; female subgenital plates of the two species are similar but the dark spots on abdominal sterna of F. songi are absent in F. tau (see figs. 275–278 in Wu 1938). When compared with F. mongolica , F. songi exhibits a simpler pale pigmentation on tergum 8; tergum 9 is posteromedially depressed without posterior swellings or sensilla basiconica; tergum 10 has a dark median spot; paraprocts lacking pale oval spots as in F. mongolica ; the paraproct lobe has a rounded apex rather than the subtriangular, narrower apex in F. mongolica (see figs. 5–7 in Teslenko et al. 2010). In females, the subgenital plate of F. songi has a shallow posterior notch, which is deep in F. mongolica ; the sclerotization of terminal sterna is also quite different between the two species (see fig. 9 in Teslenko et al. 2010). In the eggs of F. songi , the collar is simple, the anchor is completely rounded; while in F. mongolica , the collar consists of three projections, the anchor has three longitudinal ridges and a truncate apex (see figs. 10–14 in Teslenko et al. 2010). Filchneria songi can be easily separated from F. kuenluensis by the shape of subgenital plate of the female. The female subgenital plate is V-shaped in F. kuenluensis (see fig. 1B in Šámal, 1935). Dr. Valentina Teslenko (personal communication) suggested that the Korean species Perlodes stigmata Ra, Kim, Kang & Ham, 1994 is actually a Filchneria . I agree with this assignment because the upcurved male tergum 10, the bilobed female subgenital plate and the wing venation in original literature are similar to other species of Filchneria (see fig. 2 in Ra et al. 1994). Filchneria songi is apparently distinguished from this species by the shape of paraproct lobes in male, the wing venation and the color patterns of abdominal sterna in the female.

Figures

FIGURE 1. Filchneria songi sp. nov. A. male habitus, dorsal view; B. female habitus, dorsal view.

FIGURE 2. Filchneria songi sp. nov. A. right forewing, dorsal view; B. right hind wing, dorsal view.