Rediscovery of C. persicum

During a trip to southern and southwestern Iran in early summer 2015, two of us (TS and DI) found at 4 localities in mountain regions of Lorestãn and Esfahãn Provinces a small Coenagrion that was clearly different from the only other co-occurring Coenagrion, C. vanbrinkae (Lohmann, 1993) by being smaller and darker, especially on S5–7. These individuals were identified in the hand as C. persicum, because the males fit well with the description of Lohmann (1993). As females were unknown, some female specimens suspected to be of this species were also collected, some of them in tandem with males of C. persicum.

Description of the colour pattern of C. persicum males and comparison with Lohmann's description (Figs. 1 A–E, H, I, 2A, C, E). Males of C. persicum have large postocular spots that are usually weakly toothed or serrated on the rear margin. The antehumeral stripes in C. persicum males are mostly absent, with some individuals showing residual small dots (Fig. 1 D, E). This is in contrast to most of the C. pulchellum males (Fig. 1 G). In accordance with Lohmann`s description, the overall colour and pattern of C. persicum males resemble that of C. pulchellum. However, in contrast to the specimen described by Lohmann (1993), the U-marking of S 2 in all of our specimens (Fig. 1 B) is intermediate between C. puella (see e.g. Dijkstra 2006) and C. pulchellum (Fig. 1 F). Some C. persicum males have a faint to weak stalk-like connection between the base of the U-mark and the caudal marking of the caudal margin of segment 2 and the others have no connection (Fig. 1 B). The male colour pattern of S3–10 are in accordance with Lohmann`s description (Fig. 1 A). The pattern on the tergites of S3–5 has trident shapes and the lateral points reach nearly the upper margins of the segments. The middle point of S3 reaches over one half of the tergite, the middle point of S4 reaches to two-thirds of the tergite, and the middle point of S5 reaches nearly the upper margin of the segment. On S3 this black marking leaves ca. 70% blue, on S4 the blue is reduced to ca. 50%, and on S5 is up to 80% black. S6–7 are nearly completely black with small to very small blue dots. S8 is blue, S9 blue with black markings, and S10 is black.

Cerci in dorsal view resemble C. pulchellum but are coarser and chunky (Fig. 2 A–F). At mid-length on the inner margin, there is a clearly visible tooth turned inward (Figs. 1 C, 2A). Some C. pulchellum males have also a similar tooth on their cerci; however, it is located more distally, while other C. pulchellum males have no tooth (Fig. 2 B).

The outer branch of the paraprocts, in lateral view, are obliquely directed backwards in C. persicum, exceeding the cerci but not reaching mid-height of S10. These structures are first directed upright (ca. vertically), then backwards in C. pulchellum, in which they do not exceed the cerci but do exceed mid-height of S 10 in lateral view (Figs. 2 C, D). This observation differs from the description by Lohmann, in which the outer branches of the lower appendages are first directed upright in both species.

Description of females (Figs. 3 A–D, F). Females of C. persicum have large postocular spots that are usually weakly toothed or serrated on the rear margin. The pterostigma is very dark, nearly black. In contrast to males, females have complete antehumeral stripes, which are blue. Some females are very dark with S3–7 black, S1–2 and S8 blue or pale (Fig. 3 C left), reminiscent of C. armatum females (see e.g. Dijkstra 2006). Other females have more Genbank

Species Code Country Latitude Longitude Source

PRMT PGI-1219 blue and and are similar to males; however, the median point in females is much longer than the lateral points, reaching nearly the upper margin of the segment (Fig. 3 A, Fig. 3 C middle and right). In these blue females some variation was seen in the pattern of black and blue abdominal markings (Fig. 3 A, 3C middle and right). However, unlike C. pulchellum, all females observed in C. persicum have a pattern on S2 like a spearhead (Figs. 3 A, B) reminiscent of the S2 mark in C. hastulatum males (Dijkstra 2006).

The hind margin of the pronotum in C. persicum females is deeply trilobed, and the three very distinct lobes resemble at first sight the corresponding structure in C. pulchellum (Fig. 3 D). However, in contrast with the latter (Fig. 3 E), the middle lobe in C. persicum is clearly longer than the two lateral ones and more rounded than in C. pulchellum, in which it is rather pointed, and the lateral lobes are curved inward only in C. persicum. The dorsal surface of the outer lobes of the pronotum has a more pronounced relief in C. persicum (Fig. 3 D) compared with C. pulchellum (Fig. 3 E).

Measurements. Males (n =21) and females (n=5) of C. persicum are small, about 30 mm in total length (Table 2).

FIGURE 3. (continued) F–G Molecular analysis. The final dataset consisted of two alignments of 12 sequences (PRMT—706 bp long; PGI-1219—605 bp long) from 6 Coenagrion species (Table 1). The most appropriate models for the PRMT and PGI sequences were HKY+I and HKY respectively. Tree topologies from both ML and BI approaches were identical in both markers, and thus we present results from the BI majority-rule consensus tree only (Fig. 4). All of the species were recovered as distinct and well-supported branches (BI pp>0.90), although relations between species varied with the marker used.

Species pairs exhibited distinct levels of genetic divergence at both PRMT and PGI datasets given the differences in relatedness between species (1.2% ≤ PRMT uncorrected p-distance ≥ 6.2%; 0.7% ≤ PGI uncorrected p-distance ≥ 9.9 %) (Tables 3 and 4). Regarding the PRMT fragment, C. persicum exhibited approximately 1.2% sequence divergence with respect to C. pulchellum, which was the same divergence observed between the latter and either C. puella or C. ornatum. The minimum divergence observed in the PGI fragment was between C. ornatum and C. pulchellum (0.7%), while C. persicum exhibited approximately 1.9% sequence divergence with respect to either C. pulchellum or C. ornatum.

Characterization of the habitat and some notes on the behaviour. Coenagrion persicum seems to prefer running waters of small springs with rich herbaceous vegetation in and around the water (Fig. 5, above). We found C. persicum at four sites in mountain regions in Iran (Fig. 5, map), with two flourishing populations showing about one hundred individuals. One of the latter was near the type locality in Lorestãn Province (Fig. 5 (1): 33.459799°N, 49.349852°E; 1817 m; 11.VI.2015), and the other was in Esfahãn Province near Dari Sari (Fig. 5 (2): 33.249639°N, 49.947417°E; 2329 m; 12.VI.2015). These two localities were characterized as headwater areas with herb-rich brooks and ditches surrounded by wet meadows. Two further small populations with not more than 10 individuals during our visit were located in Esfahãn Province on the Annaarbar River near Noqan (Fig. 5 (3): 33.180695°N, 50.064721°E; 2235 m; 12.VI.2015) and Pelasjan River near Singerd (Fig. 5 (4): 32.823649°N, 50.429044°E; 2155 m; 12.VI.2015). Coenagrion persicum individuals were not observed flying distances of more than 2 meters, and were found resting in the vegetation in and around the water most of the time. One pair was observed laying eggs in floating vegetation (Fig. 3 G). No territorial behaviour was observed. Coenagrion persicum co-occurs with other rheophilic species such as Coenagrion vanbrinkae, Calopteryx intermedia Selys, 1887, Caliaeschna microstigma (Schneider, 1845) and Cordulegaster insignis nobilis Morton, 1916. At all localities it was much rarer than C. vanbrinkae.