Coenagrion australocaspicum

C. australocaspicum stands aside from other Coenagrion spp. in the area considered with respect to its very long male paraprocts, a character seen even by a naked eye and shared only by C. syriacum ranging in the Mediterranean coastal areas of Turkey, Syria, Lebanon and Israel (Kalkman 2006). It is remarkable that the only difference of C. australocaspicum from C. syriacum stated in the original description is as follows: “It differs, from C. ponticum and C. syriacum by the widely separated app. sup. of the males, a character it only shares with C. puella s.s. ” (Dumont & Heidari 1996). Unfortunarely, this character was not well illustrated in the original descripion, where the illustrations contradict each other. The drawings in the dorsal and caudal views show the bases of the cerci set apart from each other and laterally of the central prominence of the S10 inner side (Dumont & Heidari 1996: figs 7, 8). At the same time, the scanned electronic microphotograph shows, in caudal view, their bases disposed close to each other under the central prominence (Ibid.: fig. 4). Exactly this is seen also in our caudal view photos of C. australocaspicum from Dagestan (Fig. 4a–b) and in the photos of male specimens of C. syriacum from Adana Il of Turkey kept in RMNH, kindly provided by the curator of Odonata collection Charlotte Hartong (Fig. 16d,f). Taking into account the subjectivity of drawings, we conclude that the very bases of the cerci are set tightly close to each other in both species. The actual difference between C. australocaspicum and C. syriacum is seen in dorsal view (Fig. 2a–c vs Fig. 16b, e) and consist of the presence of inner bulges of the basal parts of the cerci in C. syriacum (Fig. 16b, e), so that they contact to each other. C. australocaspicum misses these bulges (Fig. 2a–c), so its cerci are well separated from each other indeed in dorsal view, but this is a matter of their shape rather than positions of their bases.

The original description of C. australocaspicum also mentions (but not as diagnostic) and illustrates the paraproct basoventral part with a rounded prominence, rather than an angular one, as in C. syriacum, but our specimens of C. australocaspicum from Dagestan (Fig. 3a–c) and those of Skvortzov & Snegovaya (2015) from Azerbaijan, both series being from the Caspian coast, exhibit the latter condition of angular projection.

The comparison of the photographs of male specimens of C. syriacum kept in RMNH (Fig. 16) with our specimens of C. australocaspicum from Dagestan (Figs 2a–c, 3a–c, 4a–b, 5f) showed the following morphological differences of the former species from the latter:

—the cercus has a well expressed bulge (Fig. 16b, e);

—the paraproct spine is thicker, blunter, a bit relatively shorter and very slightly skewed up rather than directed strictly caudad (Fig. 16a, d);

—the tubercle of the cerci is slanting down in C. syriacum but slightly raised in C. australocaspicum (Fig. 16a, d);

—the processes of the cerci in C. syriacum are much longer than in C. australocaspicum and protrude below the middle of the paraproct bases (Fig. 16c, f), they are straight almost like in C. pulchellum;

—the S10 dorsal margin more raised in lateral view (Fig. 16a, d).

Also there exists a steady difference in the abdominal black pattern: the males of C. syriacum always have a broad dorsal black bar on the hind part of S9 (Fig. 16; iNaturalist 2023) while the males of C. australocaspicum have S9 entirely blue, with at most a pair of black dots (Fig. 2a–c, 6a–c, j–k).