Cryptotendipes acalcar Reiss

Cryptotendipes acalcar Reiss (Figure 2) Cryptotendipes acalcar Reiss, 1990: 209. Mongolchironomus mongolkeleus Sasa & Suzuki, 1997: 161, syn. nov. Material examined. Holotype of Mongolchironomus mongolkeleus, M (NSMT-I-Dip 5054), labelled “No. 308:86”, MONGOLIA: Bogd #9, 44°40'N, 102°11'E, alt. 1500 m, 13.viii.1996, leg. H. Suzuki; 1M, 1F, CHINA: Qinghai Province, Lake Qinghai, River Heima, 36°41'N, 99°53'E, alt. 3260 m, 22.vii.2023, leg. H. Tang; 2L, as previous except 36°42'N, 99°45'E, alt. 3290 m, leg. X. Qiu, 23.vi.2016; 3M, 2 Pe, Xinjiang Province, Ruoqiang County, Lop village, Lake Tetma, 39°29'N, 88°17'E, alt. 808 m, 20.viii.2024, leg. Z. Wu; 2L, as previous except 21.viii.2015, leg. Y. Zhang; 1M, MONGOLIA: Uvs Aimag, Tes Sum, Uvs Nuur, 22.viii.2019, leg. Q. Han. Remarks. The re-examination of the holotype of Mongolchironomus mongolkeleus Sasa & Suzuki revealed that in the original description, the authors (1997: 160, fig. 12g) overlooked the heavily pigmented median longitudinal ridge (band) on the anal tergite (Fig. 2B). In addition, they illustrated the dorsal appendage as if it has a large bare base. Actually, the strange base is an interface forming a boundary between the volsella and the gonocoxite. The interface (Figs 2G, H) is easily distorted by pressure on the coverslip. Thus, the features of specimens newly collected from China are consistent with those of the holotype of M. mongolkeleus. Further, the collection information on the holotype of M. mongolkeleus contradicts the published data (Sasa & Suzuki 1997: 161). The label reads “Ulaanbaatur #20, 9.viii.1996 ”, whereas the publication lists “Bogd #9, 13.viii.1996 ”. We adopt the published data, as the original label is possible to have been revised once. Adult males collected from China have the following features: total body length 4.1–5.8 mm, wing length 1.9–2.5 mm, AR 2.45–3.00 and LR 1 1.37–1.52. These measurement data and ratios satisfy the original description of Cryptotendipes acalcar Reiss, 1990. Mongolchironomus mongolkeleus is a junior synonym of Cryptotendipes acalcar Reiss. Two barcodes for C. acalcar (DBCCT009-24, DBCCT010-24) are newly provided here based on Chinese specimens. Distribution. The species is previously only known from Turkey and Mongolia, and is now shown to occur in the northwest of China, the Lake Qinghai catchment and the southeast of Xinjiang Prefecture. The distribution is shown in Fig. 3.