Identification guide to larvae of Caucasian Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae) Author Hrivniak, Ľubos Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 37005 Ceske Budejovice, Czech Republic & Faculty of Sciences, University of South Bohemia, Branisovska 31, 37005 Ceske Budejovice, Czech Republic lubos.hrivniak@gmail.com Author Sroka, Pavel Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 37005 Ceske Budejovice, Czech Republic https://orcid.org/0000-0003-4367-6564 Author Bojkova, Jindriska Department of Botany and Zoology, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic Author Godunko, Roman J. Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 37005 Ceske Budejovice, Czech Republic & Department of Invertebrate Zoology and Hydrobiology, University of Lodz, Banacha 12 / 16, 90237 Lodz, Poland https://orcid.org/0000-0003-2196-3327 godunko@seznam.cz text ZooKeys 2020 986 1 53 http://dx.doi.org/10.3897/zookeys.986.56276 journal article http://dx.doi.org/10.3897/zookeys.986.56276 1313-2970-986-1 CDFA38CA1B6F424D85246B540E63E954 2A3CD185EDDF52BDB0AD1E5DA924299B Epeorus (Caucasiron) nigripilosus (Sinitshenkova, 1976) Figs 12 , 13 , 14 Iron nigripilosus Sinitshenkova, 1976 Epeorus (Iron) nigripilosus (Sinitshenkova, 1976); in Kluge (1995) Epeorus (Caucasiron) nigripilosus (Sinitshenkova, 1976); in Kluge (2004) Type locality. Georgia, Mtskheta-Mtianeti Region, Kistinka (= Khde, Khdistkhali) River (along the Georgian Military Road, 1300 m a.s.l.). Distribution. Georgia, south-western Russia, Turkey, Cyprus Island, northern Iraq, northern Iran (Fig. 12 ). Habitat. Larvae inhabit small streams and rivers at low to high altitude. Altitudinal range of sampling sites 280-2100 m a.s.l. (Fig. 12 ). Most frequently found above 1000 m a.s.l. Main morphological diagnostics of larvae. (i) abdominal sterna II-VI with a pair of triangular spots; nerve ganglia often with spots (Fig. 13B, J ); (ii) abdominal terga V-VII with lateral stripes extended dorso-posteriorly (Fig. 13H, I , arrows); (iii) tergum X with postero-lateral projections (Fig. 14K, L , arrows); (iv) femora with rounded medial hypodermal spot (Fig. 13F, G ); (v) setae on abdominal terga hair-like (Fig. 14E ); (vi) denticles along posterior margin of tergum VII strongly sclerotized and dense (Fig. 14E ); (vii) gill plates VII (in natural position from ventral view) wide (Figs 13K , 14H-J ); (viii) gill plates III with developed projection (Fig. 14G ). Remarks. Taxonomy . This species was described based on larvae from Georgia (Kistinka River) ( Sinitshenkova 1976 ). Type series is deposited in IZ ( Kluge 1995 ). Male imago was described by Braasch (1979) based on the material from the western Caucasus (Teberda River) associated with larvae according to similar coloration of abdominal terga and sterna. Female imago not described. Male genitalia similar to E. (C.) caucasicus according to Braasch (1979) . Figure 12. Geographical (left) and vertical (right) distribution of Epeorus (Caucasiron) nigripilosus . Figure 13. Epeorus (Caucasiron) nigripilosus , larva: A habitus in dorsal view B habitus in ventral view C habitus in lateral view D head of male in dorsal view E head of female in dorsal view F, -G middle leg in dorsal view H, -I abdominal terga (arrows point on dorso-posteriorly extended lateral stripes) J abdominal sterna II-VI K gills VII (in natural position from ventral view). Figure 14. Epeorus (Caucasiron) nigripilosus , larva: A labrum (left half in dorsal view right half in ventral view) B incisors of left mandible C incisors of right mandible D setae on dorsal surface of femora E surface and posterior margin of abdominal tergum VII F gill I G gill III H gill VII (flattened on slide) I, J gill VII (in natural position from ventral view) variability in shape K, L abdominal segments VIII-X in lateral view (arrows point on postero-lateral projection) M , sternum IX of female with observed variability.