Peltoperlopsis mengmanensis, Chen, 2019

Chen, Zhi-Teng, 2019, Peltoperlopsis mengmanensis sp. nov., the second species of Peltoperlopsis (Plecoptera: Peltoperlidae) from China, Zootaxa 4656 (1), pp. 177-182 : 178-180

Peltoperlopsis mengmanensis sp. nov.

Figs. 2–6 .

Male ( Figs. 2–6 ). Body length ca. 7.5 mm; forewing length ca. 8.5 mm, hindwing length ca. 7.5 mm. Body generally dark brown. Head strongly inserted into prothorax, oblate and generally dark brown. Biocellate; compound eyes small rounded and covered with short hairs. Antennae slender and brown, length subequal to ½ of body. Maxillary palps slender, four-segmented with shorter apical segments; labial palps short and three-segmented. Pronotum subtrapezoidal with obtuse corners, anterior margin wider than posterior margin, surface covered with distinct rugosities. Meso- and metanota generally brown. Macropterous; wings hairy and subhyaline, veins brown. In the forewing, about 18 crossveins present between C and Sc; apical area with six extra crossveins; RP with two branches; CuA with four branches; AA1 simple; AA2 forked with three branches. In the hind wing, RP with two branches; anal area large, with seven anal branches. Legs generally brown, ventral aspect of femora with two parallel ridges; tibial spur indistinct; euplantulae conspicuous and pale.

Abdominal segments generally brown; segments 2–8 divided into distinct terga and sterna. Sternum 9 extended backwards with a triangular apex; ventral vesicle pale, with an elliptical base and a subtriangular apex; two indentations present from base of the vesicle to posterolateral margins of sternum 9. Tergum 9 mostly sclerotized except for the median membranous area. Tergum 10 with a membranous median area, bearing a U-shaped epiproct sclerite; apices of the arms of epiproct sclerite curved inward. Paraprocts subtriangular, covered by sternum 9. Aedeagus asymmetrical, membranous with two large lobes, surface without spines or small lobes, basally constricted. Cerci slender and covered by long hairs, with 16–17 segments, boundary of basal segments unclear; posterior half of cerci curved inwards; basal half of cerci (about 10 segments) dark brown, other segments pale to pale brown; basal segment unmodified, length about 1.5X longer than width; segments 2–5 with irregular long hairs along inner margins, but which are absent in the paratype; segments 11–12 each with a single enlarged dorsal spine pointing inward; segment 10 with an extra smaller spine in the paratype.

Female. Unknown.

Type material. Holotype male, China: Yunnan Province, Mengla County, Mengman Town, Nanping Village , Lancang River , 800m, 21.2749 N, 101.3073 E, 15 May 2010 (ICJUST) . Paratype: one male, same locality and data as holotype (ICJUST).

Etymology. The species is named for its type locality in Mengman Town.

Remarks. The cercal spines and hairs of the male paratype differ from the holotype. This type of intraspecific variation has also been reported in Styloperlidae ( Uchida & Isobe 1989) . Therefore, these cercal characters should be treated with caution in future descriptions of new species, characters of the terminalia should be considered simultaneously.

The new species can be distinguished from all known congeners by the following combination of characters: tergum 10 with a U-shaped epiproct sclerite, apices of its arms curved inward; vesicle with an elliptical base and a subtriangular apex; cercal segments 11–12 each with an enlarged spine; aedeagus asymmetrical and bilobed. Peltoperlopsis nigrifulva , another species also known from Yunnan Province, has no U-shaped sclerite on tergum 10, no cercal spines or long hairs, and has a simple, narrow vesicle (original description in Chinese, see figs. 1–4 in Wu 1962). The cerci of the new species are somewhat similar to those found in the Vietnamese species, P. spinosa, However , in that species, no cercal spines are absent, instead numerous long thick setae occur on segments 9–13. Additionally; the shape of vesicle and aedeagus also differs from P. mengmanensis (see figs. 64–66 in Stark & Sivec 2007). Considering the current distribution of Peltoperlopsis in Southeast Asia ( Fig. 1 ), additional species of this genus are expected to be found in Laos, Thailand, Cambodia, and Hainan Island of China.

Figures

FIGURE 1. Type localities of species of Peltoperlopsis. Different species are indicated with different colors.

FIGURE 2. Peltoperlopsis mengmanensis sp. nov., holotype, A. male habitus, dorsal view; B. male habitus, ventral view; C. male head and pronotum, dorsal view.

FIGURE 3. Peltoperlopsis mengmanensis sp. nov., holotype, A. left forewing, dorsal view; B. left hindwing, dorsal view.

FIGURE 4. Peltoperlopsis mengmanensis sp. nov., terminalia of male holotype, A. dorsal view; B. ventral view.

FIGURE 5. Peltoperlopsis mengmanensis sp. nov. A. cerci of male holotype, dorsal view; B. cerci of male holotype, ventral view; C. cerci of male paratype, dorsal view; extra cercal spines indicated with red arrowheads.

FIGURE 6. Peltoperlopsis mengmanensis sp. nov., holotype, A. male terminalia after NaOH treatment, cercal structures with amplified illustrations; B. aedeagus, dorsal view.