Isoperla chongxui, Chen & Du & Li, 2021

Chen, Zhi-Teng, Du, Si-Kai & Li, Xin-Tong, 2021, Description of a remarkable new species of Isoperla (Plecoptera: Perlodidae), with supplements for Isoperla kozlovi Zhiltzova, 1972 from China, Zootaxa 5027 (2), pp. 160-174 : 161-164

publication ID	https://doi.org/ 10.11646/zootaxa.5027.2.2
publication LSID	lsid:zoobank.org:pub:61A04046-5F04-4646-8349-E7DEDDD7DB39
DOI	https://doi.org/10.5281/zenodo.5492766
persistent identifier	https://treatment.plazi.org/id/03E38793-0B2F-FFBE-FF3D-FF17905AF85B
treatment provided by	Plazi
scientific name	Isoperla chongxui
status	sp. nov.

Treatment

Isoperla chongxui View in CoL sp. nov.

Figs. 1–11 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 .

Adult habitus. Body pale to dark brown, males much darker than females ( Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 ). Head mostly pale brown, medially covered by an elliptical, dark stigma. Triocellate, anterior ocellus slightly smaller than posterior ones; compound eyes small and rounded. Antennae slender, generally dark brown, basal segments pale, subequal in length to the abdomen. Maxillary palps slender, four-segmented with a strongly reduced apical segment reminiscent of Chloroperlidae ; labial palps shorter, three-segmented with a strongly reduced apical segment. Pronotum subrectangular with angled corners; median half of pronotum rugose and dark brown, lateral areas pale. Macropterous; wings hyaline, veins brown. Legs generally pale brown; two large tibial spurs present. Abdominal segments mostly dark brown in males, pale in females. Cerci slender, shorter than the abdomen, mostly pale, apically dark brown.

Male. Body length 8–10 mm (N = 5); forewings length ca. 8.0 mm, hindwings length ca. 6.5 mm ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ). In the forewing, RP with two branches; CuA with three to four branches; AA1 simple, AA2 forked. In the hind wing, RP with two branches; anal area large and folded with eight anal branches.

Abdominal tergum 1 completely sclerotized. Terga 1–9 with membranous median areas ( Fig. 5 View FIGURE 5 ). Lateral areas of terga 5–6 slightly humped ( Figs. 5–6 View FIGURE 5 View FIGURE 6 ). Terga 7–9 each with a pair of strongly elevated lateral lobes, the lobes gradually enlarged towards posterior segments ( Figs. 5–6 View FIGURE 5 View FIGURE 6 ). Posteromedial margin of tergum 9 rounded and sclerotized. Tergum 10 mostly sclerotized except for the posteromedial membranous area ( Fig. 5D View FIGURE 5 ). Paraprocts triangular, rising to height of 10th tergum, hook-shaped and curved anteriorly, apices pointed ( Figs. 5D, G View FIGURE 5 , 6A, B View FIGURE 6 ). Vesicle poorly developed,>2X wider than long, reduced into an elliptical patch of dark hairs on posteromedial margin of sternum 8 ( Fig. 7 View FIGURE 7 ). Sternum 9 broadly produced, expanded backwards with a truncate apex ( Fig. 7A, B View FIGURE 7 ). Aedeagus membranous, basoventrally with an elliptical spinule patch, apically with a spinulose lobe connected with a longitudinal stripe of dense spines; lateral membranous lobes present on apex of aedeagus ( Fig. 8 View FIGURE 8 ).

Female. Body length 12.5–13.5 mm (N = 5) ( Figs. 3–4 View FIGURE 3 View FIGURE 4 ).Abdominal segments pale.Tergum 10 with subtriangular posterior margin ( Fig. 9A View FIGURE 9 ). Subgenital plate broad, gradually tapered towards apex, covering anterior ⅓ of sternum 9, posterior margin with a shallow notch ( Fig. 9B View FIGURE 9 ). Paraprocts subtriangular with pointed apices ( Fig. 9 View FIGURE 9 ). The immature eggs rounded in shape; collar short, cylindrical; anchor near rounded from view of the anchor pole, surface without granules; chorionic surface with hexagonal follicle cell impressions ( Fig. 10 View FIGURE 10 ).

Type material. Holotype male, China: Henan Province, Xinyang City, Dongzhai National Nature Reserve ( Fig. 11 View FIGURE 11 ), 31.94956609° N, 114.25485947° E, 160 m, 6-IV-2021, Si-Kai, Du ( ICJUST) GoogleMaps . Paratypes: four males and five females, same locality and date as holotype ( ICJUST) GoogleMaps .

Etymology. The species is named for Mr. Xu Chong who has helped the authors in previous works.

Remarks. The new species can be easily distinguished from its congeners by the presence of projected lobes on male abdominal terga 7–9 and smaller humps on previous tergal segments. In I. sextuberculata , the finger-shaped lobes are present on terga 4, 7 and 8 ( Huo & Du 2020). Other species of Isoperlinae with abdominal processes include Isoperla distincta Nelson, 1976 from North America, Kaszabia digitata ( Kawai, 1963) , Isoperla sp. ( Maruyama & Hanada 2016) from Japan, and Kaszabia nigricauda ( Navás, 1923) from Mongolia and Russia. Locations of tergal lobes on these species are on different segments than those found on the new species.