Parisoperla Huo & Du, 2020

Huo, Qing-Bo & Du, Yu-Zhou, 2020, A new genus and two new species of stoneflies (Plecoptera: Perlodidae) from Guizhou Province, China, Zootaxa 4718 (4), pp. 470-480 : 471

Parisoperla Huo & Du , gen. nov.

Diagnosis: Small size, body length 10~ 15 mm; macropterous, wing length 10~ 15 mm, general color dark brown; triocellus, area between posterior ocelli to compound eyes yellow brown. Pronotum width twice its length, darkcolored medially with rugosities, with a smooth longitudinal band present among the centerline. Terga 9–10 of male heavily sclerotized posteriorly, posteromedial margin of tergum 10 undivided, with a developed sclerotized process ( Fig. 1 A–B) with wide lateral grooves on surface. Vesicle on sternum 8 reduced. Aedeagus membranous, short columnar, without any sclerites but covered ventrally by patches of fine spines. Female coloration similar to male, posterior margin of tergum 10 usually sclerotized and extending as a process like the male ( Fig. 1 C–D). Subgenital plate rounded or short triangle, often with a median notch apically.

Type species: Parisoperla oncocauda ( Huo & Du, 2018) .

Etymology: This name indicates “ Para -” and “ Isoperla ”, means that “similar to Isoperla ”.

Remarks: We previously treated P. oncocauda as a species of Isoperla Banks, 1906 based on the wing venation ( Banks 1906) and aedeagal morphology ( Sandberg & Kondratieff 2013, Szczytko & Kondratieff 2015). The wing venation and the paraprocts of Parisoperla are most similar to Isoperla , indicating a placement in the subfamily Isoperlinae . Within the Isoperlinae , several genera such as Calliperla Banks, 1948 , Cascadoperla Szczytko & Stewart, 1979 , Clioperla Needham & Claassen, 1925 , Cosumnoperla Szczytko & Bottorff, 1987 , Kaszabia Raušer, 1968 and Mesoperlina Klapálek, 1921 are also similar to the new genus. However, the male tergum 10 of Clioperla and Mesoperlina is cleft. The male of Kaszabia can be distinguished by a pair of tergal processes of the abdomen (although these processes are not a unique character of this subfamily, present also I. distincta Nelson, 1976 a Nearctic species of Isoperla ) ( Teslenko & Zhiltzova 2009, Judson & Nelson 2012, Szczytko & Kondratieff 2015); The monotypic Calliperla from western North America has the male tergum 10 short and broad, crescent-shaped, with a terminal process as well, but the process curving forward and upward, just as similar as Cosumnoperla . The aedeagus of Calliperla and Cosumnoperla are more complex in structure than the new genus ( Bottorff 2007, Szczytko & Stewart 1984).

Discussion: Geographically, the 15 known Chinese Isoperla species are mainly distributed in Palaearctic Region of China. Whereas Parisoperla is apparently restricted to Guizhou and Zhejiang provinces, which are considered the northern portion of the Oriental Region ( Ma 1959, Zhang 2011). Therefore, we speculate that the genus may be an Oriental group of stoneflies.

Figures

FIGURE 1. Type species, Parisoperla oncocauda (Huo & Du, 2018). A–B: male terminalia, dorsal and lateral view; C–D: female terminalia, dorsal and lateral view.