Monodiamesa bathyphila, (Kieffer, 1918)

Han, Wu, Tang, Hongqu & Ni, Zhenyu, 2021, DNA barcodes and morphology reveal two new species of Monodiamesa Kieffer (Diptera: Chironomidae: Prodiamesinae) in Tibetan Plateau, Zootaxa 4990 (1), pp. 81-103 : 97-98

M. bathyphila ( Kieffer, 1918)

For M. bathyphila , the most important early publication is not Kieffer (1918) but Thienemann (1919) because it provided a more detailed description according to emerged adults that emerged from mass-reared larvae in the laboratory (Martin Spies pers. comm. 2021). The male adult of European M. bathyphila is characterized by the following: AR 2.0, LR 0.80, BR 4.0–5.0 and the similar terminal level of two appendages. In addition, two features unmentioned in previous description were noted by Martin Spies (pers. comm. 2021) after checking the non-type materials deposited in ZSM. They are the presence of two tubercule-based setae on the basal median lobe and a weakly sclerotized boundary between the pedestal and the distal spine of MVo.

M. bathyphila has been recorded frequently also in Japan and the Russia Far East by Japanese and Russian researchers ( Tokunaga 1936; Makarchenko 1985; Sasa and Kawai 1987). Two Japan species Prodiamesa chuzenigra Sasa, 1989 and Prodiamesa kamidefea Sasa & Hirabayashi 1993 were synonymized as junior synonyms of M. bathyphila by Kobayashi and Endo (2008). Interestingly, the line illustration of P. chuzenigra (previously as Prodiamesa sp. sensu Sasa, 1984, synonymized as M. bathyphila latter, see above) shows a clear boundary between the pedestal and distal spine (1984: p.210, fig. 92G), which contrasts with Tokunaga’s work. We compared this illustration with its Japanese digital holotype ( Figs. 10A–B ) stored at National Museum of Nature and Science Type Specimen Database (http://www.type.kahaku.go.jp/, Reg. No: 052:001). The photos of the holotype P. chuzenigra bearing nearly uniform pigmentation of MVo like P. kamidefea (Reg. No: 239:095). Combined with Yamamoto’s illustration ( Figs. 10C–D ), we assumed that the Japanese population most likely bears a weak boundary between the pedestal and distal spine as that in European population, which is hard to discern and not as clear as in the illustration of P. chuzenigra . When we compared eastern Palaearctic population under the name M. bathyphila with European counterparts, some differences in male adults were revealed. Apart from the different color pattern mentioned by Tokunaga (1936), eastern Palaearctic populations have a higher AR value (2.43–3.30) than European population. The molecular result has supported that Russian FE and Korean population are different from European population, but deficiency of barcodes from Japanese and Chinese population hinders further determining whether eastern Palaearctic populations under the name M. bathyphila include more cryptic species. However, if the suspicion that Japanese population is an independent species is verified, Monodiamesa chuzenigra ( Sasa, 1984) will have the name priority.

All previous records of this species in Chinese literatures are unreliable since the identifications were based solely on larval material ( Wang and Zheng 1992).

Figures

FIGURE 10. Monodiamesa bathyphila (Japanese population). Photos: (A–B) hypopygium. (Prodiamesa chuzenigra, from NMNS, No: 052:001); (C–D) hypopygium. (illustrated by Masaru Yamamoto). Scale bar: A–D, 100 μm.