Leuctra fusca ssp. ( Linnaeus, 1758 ) (Linnaeus, 1758)

Murányi, Dávid, Manko, Peter, Kovács, Tibor, Vinçon, Gilles, Žiak, Matej, Kerimova, Ilhama G., Snegovaya, Nataly Yurievna & Oboňa, Jozef, 2021, Review and contribution to the stonefly (Insecta: Plecoptera) fauna of Azerbaijan, Zootaxa 4975 (1), pp. 58-80 : 66

Leuctra fusca ssp. ( Linnaeus, 1758)

Lənkəran region: 1: 9♂ 7♀ (HNHM); 2 : 4♂ 1♀ (HNHM); 4: 5♂ 4♀ (HNHM), 1♂ (LMEE); 5: 1♂ 2♀, 1 exuviae (HNHM); 7: 1♂ 4♀ (HNHM); 8: 4♂ 2♀ (HNHM); 9: 3♂ 1♀ (HNHM); 10: 3♂ 4♀ (HNHM), 1♂ 1♀ (LMEE); 12: 3♂, 6 larvae (HNHM); 13: 1♂ (HNHM), 1♀ (LMEE); 14: 6♂ 2♀ (HNHM); 15: 9♂ 6♀ (HNHM), 1♂ 2♀ (LMEE); Gəncə-Qazax region: 37: 1♂ (MM); 38: 2♂ 4♀ (HNHM), 2♂ (LMEE), 1♀ (MM); 40: 2♀ (HNHM), 2♂ 1♀ (MM); 41: 1♂ 1♀ (HNHM), 1♂ (LMEE); 42: 4♂ 4♀ (HNHM), 2♂ 1♀ (LMEE), 2♂ 3♀ (MM); 43: 1♀ (HNHM), 1♂ (SNM); 45: 1♂ 2♀ (HNHM), 1♂ (MM).

Remarks. The species has a wide Eurosiberian distribution, with three described subspecies ( Murányi & Hwang 2017). It is an autumnal potamal species over most of its range, however, Caucasian populations were noted by their uncommonly wide range of habitats occupied, from rivers to high mountain brooks (Zhiltzova 2003). Winter occurrence in Adjaria, Georgia, was recently recorded ( Teslenko et al. 2019). Indeed, Azerbaijani specimens were found in extremely different habitats during our sampling both in the Lesser Caucasus and the Talysh Mts ( Figs. 7–10 ). It is the most common autumnal stonefly in Azerbaijan, it occurs both as the single stonefly species of the given waterflow, or with a diverse community. These are the first exact data from Azerbaijan.

The subspecific identity of the Azerbaijan population is problematic. We expect L. fusca latior Berthélemy & Dia, 1982 since this subspecies inhabits the whole of Anatolia, the Levant and Iran ( Darilmaz et al. 2016, Murányi 2005, Vinçon et al. 2013). However, females of L. fusca latior are distinguished by the widely separated posterior lobes of the subgenital plate, while all the Azerbaijani females we have examined have narrowly separated lobes and possess a small, triangular median lobule slightly reminiscent of L. kurui Kazanci, 1983 . Coloration of the subgenital plate varies by age but the general shape of the subgenital plate and the spermathecal ring are constant among all of our female specimens ( Figs. 5–6 ). The male paraproct and specillum more or less agree with the description of L. fusca latior ( Figs. 3–4 ) but Azerbaijani specimens exhibit a highly reduced or entirely lacking posteromedial sclerite on tergum VIII and the posteromedial sclerite is entire or only slightly subdivided on tergum IX ( Fig. 2 ). The anterior lobes of tergum X are moderately large, the ventral vesicle small, the epiproct is wider than long with a short, weakly separated rod. Both male and female specimens vary in size and coloration, but we found no correlation of these features with the slight variability of the genitalia.

Figures

FIGURES 7–10. Habitats of Leuctra fusca ssp. (Linnaeus, 1758) in Azerbaijan—7: forest stream in the Talysh Mts, site 15; 8: forest brook in the Lesser Caucasus, site 38; 9: large stream in the Lesser Caucasus, site 41; 10: temporary, open brook in the Lesser Caucasus, site 45.

FIGURES 2–6. Morphology of Leuctra fusca ssp. (Linnaeus, 1758) from the Talysh Mts—2: male terminalia, dorsal view; 3: male paraproct and specillum, lateral view; 4: same, ventrocaudal view; 5: female terminalia, ventral view, matured specimen; 6: same, young specimen—scale 0.5 mm.