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) iranicus (Braasch & Soldan , 1979) Figs 21 , 22 , 23 Iron caucasicus iranicus Braasch & Soldan , 1979 Epeorus (Caucasiron) caucasicus iranicus (Braasch & Soldan , 1979); in Bojkova et al. (2018) Epeorus (Caucasiron) iranicus (Braasch & Soldan , 1979); in Hrivniak et al. (2020b) Type locality. Iran, Tehran Province, river in the Darban-Tal (Darban Valley), 2100 m a.s.l. Distribution. Northern Iran. Species endemic to the Alborz Mountains (Fig. 21 ). Habitat. Larvae inhabit streams at altitudes above 2000 m a.s.l. in the western and central Alborz. Altitudinal range of sampling sites 2020-2440 m a.s.l. (Fig. 21 ). Often syntopic with E. (C.) alborzicus . Main morphological diagnostics of larvae. (i) abdominal sterna II-VI with a pair of oblique stripes; nerve ganglia often with stripes or spots (Fig. 22B, I, J ); (ii) abdominal terga V-VII with stripe-like medial macula and a pair of distinct antero-lateral stripes (Fig. 22G , arrows); (iii) femora with rounded medial hypodermal spot (Fig. 22F ); (iv) gill III with well-developed projection (Fig. 23G ); (v) setae on abdominal terga hair-like (Fig. 23E ); (vi) tergum X with poorly developed postero-lateral projections (Fig. 23K , arrow) or without postero-lateral projections (Fig. 23L ). Remarks. Morphology . Coloration pattern on abdominal sterna as in E. (C.) caucasicus (Fig. 4J ), similar pattern in E. (C.) zagrosicus (Fig. 46I ). Taxonomy . This species was described as a subspecies of E. (C.) caucasicus based on larvae collected in the Alborz Mts. ( Braasch and Soldan 1979 ). Elevated to species level by Hrivniak et al. (2020b) based on a phylogenetic analysis of all Caucasian Epeorus (Caucasiron) species. The holotype probably lost. Paratypes are currently deposited in SMNS and Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Ceske Budejovice , Czech Republic (IECA). Imagines and subimagines not described. Figure 21. Geographical (left) and vertical (right) distribution of Epeorus (Caucasiron) iranicus . Figure 22. Epeorus (Caucasiron) iranicus , 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 middle leg in dorsal view G, H abdominal terga (arrows point antero-lateral stripes of medial macula) I, J abdominal sterna II-VI K gills VII (in natural position from ventral view). Figure 23. Epeorus (Caucasiron) iranicus , 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 gill VII (in natural position from ventral view) J sternum IX of female K, L abdominal segments VIII-X in lateral view (arrow points on postero-lateral projection).