Isoperla chongxui Chen & Du & Li 2021, sp. nov.
Creators: name: Chen, Zhi-Teng
name: Du, Si-Kai
name: Li, Xin-Tong
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Plecoptera
Perlodidae
Isoperla
Isoperla chongxui

description: Isoperla chongxui sp. nov.
Figs. 1–11.
Adult habitus. Body pale to dark brown, males much darker than females (Figs. 1–4). 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). 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). Lateral areas of terga 5–6 slightly humped (Figs. 5–6). Terga 7–9 each with a pair of strongly elevated lateral lobes, the lobes gradually enlarged towards posterior segments (Figs. 5–6). Posteromedial margin of tergum 9 rounded and sclerotized. Tergum 10 mostly sclerotized except for the posteromedial membranous area (Fig. 5D). Paraprocts triangular, rising to height of 10th tergum, hook-shaped and curved anteriorly, apices pointed (Figs. 5D, G, 6A, B). Vesicle poorly developed,>2X wider than long, reduced into an elliptical patch of dark hairs on posteromedial margin of sternum 8 (Fig. 7). Sternum 9 broadly produced, expanded backwards with a truncate apex (Fig. 7A, B). 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).
Female. Body length 12.5–13.5 mm (N = 5) (Figs. 3–4).Abdominal segments pale.Tergum 10 with subtriangular posterior margin (Fig. 9A). Subgenital plate broad, gradually tapered towards apex, covering anterior ⅓ of sternum 9, posterior margin with a shallow notch (Fig. 9B). Paraprocts subtriangular with pointed apices (Fig. 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).
Type material. Holotype male, China: Henan Province, Xinyang City, Dongzhai National Nature Reserve (Fig. 11), 31.94956609° N, 114.25485947° E, 160 m, 6-IV-2021, Si-Kai, Du (ICJUST). Paratypes: four males and five females, same locality and date as holotype (ICJUST).
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.
description: Published as part of 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, pp. 160-174 in Zootaxa 5027 (2) on pages 161-164, DOI: 10.11646/zootaxa.5027.2.2, http://zenodo.org/record/5448186