Coenagrion ornatum (Selys, 1850)

Kosterin, Oleg E., Onishko, Vladimir V., Ilyina, Elena V., Chepurnov, Grigory Yu. & Blinov, Alexander G., 2024, The genus Coenagrion Kirby, 1890 (Odonata: Coenagrionidae) in the Russian part of the Caucasus, Zootaxa 5471 (2), pp. 151-190 : 181

Coenagrion ornatum

Skvortsov (2010) and Skvortsov & Snegovaya (2015) raised concern about reality of the species Coenagrion vanbrinkae Lohmann, 1993 (originally proposed in an incorrect grammatical gender, as C. vanbrinki , see van Tol (1994)) and its presence in the Caucasus and Transcaucasia. This species was described from Iran and the eastern Turkey as differing from C. ornatum with just one seemingly distinct character: the male cerci diverged in the dorsal view rather than almost contacting with their tips, other characters mentioned in the original description ( Lohmann 1993) being negligible. Kosterin & Ahmadi (2018) analysed this character from the regions of Central Iran close to the type locality (Dorud) and found both versions of the cerci position in subequal frequencies. They concluded that this is a matter of position of a movable appendages rather than their structure and so, following Boudot & Kulijer (2015), considered C. vanbrinkae as a pure junior synonym of C. ornatum . This treatment is adopted in the World Odonata List ( Paulson et al. 2024) . Skvortsov & Snegovaya (2015: 36) claimed that “a more detailed comparison” of the Azerbaijanian specimens under scanning electron microscope “shows that all the specimens are intermediate” between ornatum and vanbrinkae . This agrees with a continuously variable degree of the cerci divergence in our specimens from Dagestan ( Fig. 10 ), that is in favour of synonymy of C. ornatum and C. vanbrinkae . Curiously and in contrast to the above, our specimens from Central Iran could be classified to two distinct classes of broadly divergent versus almost not diverged cerci ( Kosterin & Ahmadi 2018). There are some unpublished data hinting that specimen series of C. ornatum from the same region collected by different persons may strongly differ in the proportion of males with diverged vs non-diverged cerci, which may be interpreted so that the position of male cerci may depend on the method of killing of voucher specimens.

Figures

FIGURE 10. Male appendages of Coenagrion ornatum specimens from Dagestan in dorsal view: a–b—Rutul District, the Samur River left arm between Kufa and Kala villages, 26.06.2021; c–d—Tabasaran District, the Rubas River valley 2.5 km NE of Sirtych village, a swampy Dzharag-Khyan Spring, 28.05.2023. Scale bar 0.5 mm.