The species of Tibetisoperla (Plecoptera: Perlodidae)

1,4 Henan International Joint Laboratory of Taxonomy and Systematic Evolution of Insecta Henan Institute of Science and Technology, Xinxiang, Henan 453003, China. 2 Key Laboratory of Medicinal Animal and Plant Resources of Qinghai-Tibetan Plateau in Qinghai Province, School of Life Science, Qinghai Normal University, Xining, 810008, China. 3 Kırşehir Ahi Evran University, Vocational School of Technical Sciences, Department of Plant and Animal Production, 40100, Kırşehir, Turkey.


Introdu ction
The perlodid genus Tibetisoperla Huo & Du, 2021 was recently erected as a monotypic genus for Tibetisoperla wangluyui Huo & Du, 2021 under the subfamily Isoperlinae Frison, 1942(DeWalt et al. 2021. The males of this genus were ch aracterized by having a simplifi ed aedeagus, a spiny apical sclerite of paraproct, divided tergum 10 and reduced vesicle (Huo & Du 2021), presently it is confi ned to Tibe t Autonomous Region of southwestern China. The females cannot be distinguished from related genera. In the present paper, two additional new species of Tibetisoperla, T. elongata sp. nov. and T. sclerotica sp. nov., are described. Yang & Li (2018) list only one perlodid genus from Qinghai Province, therefore these new species and T. wangluyui also represent the fi rst record of this genus for Qinghai.

Materia l and method s
All adults were collected using an aerial net. The aedeagi were everted by squeezing the abdomen of live males before they were preserved in 95% ethanol. The male terminalia were cleared in 10% NaOH. The types and other examined specimens are deposited in the Entomological Museum of China Agricultural University (CAU), and in the Henan Institute of Science and Technology, Xinxiang (HIST). Specimens were examined with the aid of a Leica S8APO dissecting microscope and the color photographs were made with a Leica M205FA. The morphological terminology follows that of Huo & Du (2021).

Diag nos is
General color brownish. Vesicle developed and tongue-shaped, which is almost as long as its width. Aedeagus mostly membranous, except for a v-shaped ventrobasal sclerite, generally tubular and slightly curved ventrally at apex. Subgenital plate in female produced and subquadrate, posteriorly with a broad arcuate posteromedial notch.

Etymology
The specifi c epithet refers to the vesicle being long, which was presumed to be atypical for this genus.

Distribution
China: Qinghai Province. Presently only known from two sites along the riverside of Daitong River in Menyuan County.

Remarks
The type species of Tib etiso perla, T. wangluyui Huo & Du, 2021 is a dark species and has a reduced vesicle on sternum 8, but the new species is a brownish species and has a developed vesicle which is present in typical Isoperla Banks, 1906(Teslenko & Zhiltzova 2009Murányi 2011;Szczytko & Kondratieff 2015;Cao et al. 2020), another genus of Isoperlinae in China. However, the large apical setae of tergum 10 and spiny apical sclerite of paraproct clearly show its placement in Tibetisoperla. The female of T. elongata is different to T. wanglu yui in subgenital plate structure, the former is broadly semicircular while the latter is subquadrate. Additionally, T. elongata with a typically posterior notch which is indistinct of T. sclerotica. Terga 1-8 of female with black medial stripes and subgenital plate is broadly triangular in T. sclerotica.

Diagnosis
General color dark brown. Vesicle reduced to a black transverse band. Ventrobasal sclerite of aedeagus black, generally subquadrate in outline with a triangular postcentral notch.

Etymology
The specifi c epithet refers to the sclerotized ventrobasal sclerite of everted aedeagus.

Distribution
China: Qinghai Province. Presently only known from Menyuan County.

Remarks
The new species closely resembles T. wangluyui Huo & Du, 2021 in dark body coloration and reduced vesicle on sternum 8, but it is easily separated from that species by the large ventrobasal sclerite of aedeagus which is entirely membranous in T. wangluyui.

Distribution
China: Tibet and Qinghai provinces. Two males represent the fi rst record for Qinghai Province.

Remarks
This dark brown species is characterized by reduced vesicle with semicircular posterior margin and membranous aedeagus lacking sclerite. Two males examined here represent the fi rst record for Qinghai Province.

Discussion
The Isoperlinae Tibetisoperla present remarkable morphologic al differences from other genera of this subfamily (Huo & Du 2021). Together with the fi nding of these two additional species, bilobate posterior half of tergum 10 with large apical setae and a spiny apical sclerite of paraproct appear consistent with the type species, and should be considered the generic characters. Whether the aedeagus is with or without a sclerite, or sternum 8 has a developed or reduced vesicle, proved to be variable in this genus. The genus was originally known from Tibet and soon found in Qinghai Province of China in this study. The present discovery may allude to a higher diversity of Tibetisoperla on a wider geographical scale.