Megalestes riccii Navás, 1935

Yu, Xin & Xue, Junli, 2020, A review of the damselfly genus Megalestes Selys, 1862 (Insecta: Odonata Zygoptera: Synlestidae) using integrative taxonomic methods, Zootaxa 4851 (2), pp. 245-270 : 264

Megalestes riccii Navás, 1935

( Figs. 3 m–p; 4m–p; 5j–l, y–aa; 6k; 8)

Megalestes riccii Navás, 1934: 89–90 , fig. 55, “Kuling, Kiang-si” [Lushan, Jiangxi]; Chao 1962: 27–28, figs. 9–12; Chao 1965: 188–189, figs. 1–3.

Megalestes maai Chen, 1947: 27 , figs. 1–4 [ Taiwan]; Chao 1965: 189, figs. 5–8 [ Taiwan]. Syn. nov.

Megalestes tuska Wilson & Reels, 2003: 258–259 , figs. 52–63, [Damingshan, Guangxi]. Syn. nov.

This is an intermediate-sized, pale-colored species, usually with a very bright yellow color pattern, especially when young ( Fig. 2 ). The most conspicuous character of M. riccii is the yellow-colored cerci. This species is distributed in Guangxi, Hunan, Jiangxi, Taiwan, and Zhejiang.

There were three named species of Megalestes that have yellow-colored cerci, M. riccii , M. maai , and M. tuska , all endemic to China. Megalestes maai is restricted to Taiwan. We examined a series of type specimens of M. riccii deposited in IZAS and IEAS, as well as photos of the holotype of M. tuska , kindly provided by Dr. Guanhong Huang from the Agriculture, Fisheries and Conservation Department of Hong Kong. After studying our series of specimens, including four specimens of M. maai kindly provided by Mr. Wen-chi Yeh and Dr. Liang-jong Wang from Taiwan, we found no distinct differences among these three. Molecular analysis also implied that they were the same species ( Fig. 7 ). Chao (1965) compared a single male of M. maai from Taiwan with type specimens of M. riccii and the results indicated that M. maai was different from M. riccii in the longer wings and the obtuse tip of the basal tooth on the paraproct. However, among our series of specimens, the body sizes of some Zhejiang individuals ( M. riccii ) were larger than those from Taiwan ( M. maai ), and the shape of the paraproct basal tooth tip varied randomly. Wilson & Reels (2003) mentioned that M. tuska has “sharply pointed, bifurcated” tips of the basal tooth on the paraproct. Again, as discussed above, there is also intraspecies variation since our specimens show that both M. tuska and M. riccii can have the tips obvious or not, and “bifurcated” or not. One individual from Jinxiu (very near the type locality of M. tuska ) even has a very long and pointed tip ( Fig. 4p ). Thus, we believe that M. maai and M. tuska are both junior synonyms of M. riccii .

Figures

FIGURE 2. Photos of male Megalestes riccii showing color changes with maturing.

FIGURE 3. Caudal appendages of males (dorsal view). a) australis; b) irma, paratype; c) distans, from Yaan, Sichuan; d) distans from Dashahe, Guizhou; e) heros; f) omeiensis, paratype; g) kurahashii; h) major; i) haui; j) “palaceus”; k) micans, bd: basal disk; l) “chengi”; m) riccii; n) “maai”; o) “tuska,” from Damingshan, Guangxi; p) “tuska,” from Jinxiu, Guangxi. (Scale bar = 0.5 mm).

FIGURE 4. Caudal appendages of males (lateral view). a) australis; b) irma, paratype; c) distans, from Yaan, Sichuan; d) distans from Qingchengshan, Chengdu, Sichuan; e) heros; f) omeiensis, paratype; g) kurahashii; h) major; i) haui; j) “palaceus”; k) micans; l) “Chengi,” paratype; m) riccii; n) maai; o) tuska, from Damingshan, Guangxi; p) tuska, from Jinxiu, Guangxi. (Scale bar = 0.5 mm).

FIGURE 7. Phylogenetic reconstruction from ITS data modified based on BI and ML trees, with both posterior probabilities (right) and bootstrap values (left) shown.