Epeorus (Caucasiron) magnus (Braasch, 1978)

Hrivniak, Ľubos, Sroka, Pavel, Bojkova, Jindriska & Godunko, Roman J., 2020, Identification guide to larvae of Caucasian Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae), ZooKeys 986, pp. 1-53 : 1

Epeorus (Caucasiron) magnus (Braasch, 1978) Figs 9 , 10 , 11

Iron znojkoi Tshernova, 1938; in Sinitshenkova (1976), partim

Iron magnus Braasch, 1978

Epeorus (Iron) magnus (Braasch, 1978); in Kluge (1988)

Epeorus (Caucasiron) magnus (Braasch, 1978); in Kluge (1997b)

Type locality.

Russia, Krasnodar krai, western Caucasus, Sochi River (20 km above Sochi; 800 m a.s.l.).

Distribution.

Georgia, south-western Russia, Azerbaijan, Armenia, Turkey (Fig. 9 ). One of the most widespread species in the Caucasus.

Habitat.

Larvae inhabit streams and rivers of various sizes, from larger braided low-altitude rivers to small streams at high altitude. Altitudinal range of sampling sites 6-2474 m a.s.l. (Fig. 9 ). Most frequently found at low and middle altitude. Often syntopic with E. (C.) znojkoi .

Main morphological diagnostics of larvae.

(i) shape of head in male and female oval, trapezoidal (Fig. 10D, E ); (ii) tergum X with well-developed postero-lateral projections (Fig. 11K-M , arrows), sporadically poorly developed; (iii) abdominal sterna without coloration pattern (Fig. 10B, J ); (iv) abdominal terga V-VII with triangular medial macula (Fig. 10H ), sporadically poorly visible (Fig. 10I ); (v) femora without medial hypodermal spot (Fig. 10F, G ); (vi) dorsal surface of labrum densely covered by bristle-like setae (Fig. 11A ); (v) setae on abdominal terga hair-like (Fig. 11E ); (vi) gill plates III with well-developed projection (Fig. 11G ); (vii) denticles along posterior margin of tergum VII strongly sclerotized, dense and curved (Fig. 11E ).

Remarks.

Morphology. The largest species occurring in the Caucasus. The body size of larvae 20-24 mm, cerci 20-22 mm ( Braasch 1978).

Taxonomy. Original description based on the larvae from Russia (western Caucasus) ( Braasch 1978). The type series is currently deposited in the collection of Stuttgart State Museum of Natural History, Stuttgart, Germany (SMNS). Imagines (male and female) and female subimago described by Braasch (1980) based on material from Russia, Armenia and Georgia. We assume the larva of E. (C.) magnus was erroneously described under the name znojkoi by Sinitshenkova (1976) (see remarks to E. (C.) znojkoi s. l. for details).

Figures

Figure 9. Geographical (left) and vertical (right) distribution of Epeorus (Caucasiron) magnus.

Figure 10. Epeorus (Caucasiron) magnus, 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 J abdominal sterna II-VI K gills VII (in natural position from ventral view).

Figure 11. Epeorus (Caucasiron) magnus, larva: A labrum (left half in dorsal view right half in ventral view) with detail of bristle-like seta 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-M abdominal segments VIII-X in lateral view (arrow points on postero-lateral projection) N sternum IX of female with observed variability.