Mayflies of the genus Epeorus Eaton, 1881 s.l. (Ephemeroptera: Heptageniidae) from the Caucasus Mountains: a new species of Caucasiron Kluge, 1997 from Georgia and Turkey

Abstract

The new species Epeorus (Caucasiron) bicolliculatus sp. nov. is described based on larvae and adults. Diagnostic characters are given with regard to the related species. The most pronounced difference is represented by protuberances on larval abdominal terga II-IX, present exclusively in E. (C.) bicolliculatus sp. nov. Primary data on the biology and distribution of the new species are also provided. Delimitation of the new species is verified by the analysis of COI (barcode) sequences. Barcode data for all Caucasian species of the subgenus Caucasiron are provided for the first time and compared with E. (C.) bicolliculatus sp. nov.

Identification guide to larvae of Caucasian Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae)

“…Original descriptions of individual species were used for the initial species identification based on morphology (Sinitshenkova 1976;Braasch 1978Braasch , 1979Braasch , 1980Braasch and Zimmerman 1979;Braasch and Soldán 1979;Hrivniak et al 2017Hrivniak et al , 2019Hrivniak et al , 2020a. Due to insufficient details given in several of these descriptions, newly collected specimens (both larvae mounted on slides and larvae stored in ethanol) were compared with the type material (holotypes and/or paratypes) to accurately identify the species.…”

“…The available identification keys deal with selected genera only (Sinitshenkova 1976: Epeorus Eaton, 1881and Rhithrogena Eaton, 1882Jacob andZimmerman 1978: Baetis Leach, 1815) or mayfly fauna of the wider region without sufficient information on Caucasian species specifically (Kluge 1997a). These keys are largely outdated, because the number of species newly described from the Caucasus has been steadily increasing in recent years (e.g., Hrivniak et al 2017;2019;2020a;Martynov and Godunko 2017;Bojková et al 2018). Therefore, the identification of larvae to the species level is complicated due to the necessity of compiling information from original descriptions and requires advanced experience with the taxonomy of mayflies and comparative collections.…”

“…This identification guide deals with 14 species inhabiting the Caucasus and neighbouring mountain ranges, such as the Zagros and Taurus Mountains, and one species inhabiting Samos Island. The extralimital species E. (C.) guttatus (Braasch, 1979) from Central Asia, E. (C.) extraordinarius Chen et al, 2010 from south-western China, and other Central Asian species presumably belonging to the genus Caucasiron (Hrivniak et al 2017) are not included. All 15 species included in the guide are easily distinguishable based on both morphology and molecular data (Hrivniak et al 2017(Hrivniak et al , 2019(Hrivniak et al , 2020a.…”

“…The extralimital species E. (C.) guttatus (Braasch, 1979) from Central Asia, E. (C.) extraordinarius Chen et al, 2010 from south-western China, and other Central Asian species presumably belonging to the genus Caucasiron (Hrivniak et al 2017) are not included. All 15 species included in the guide are easily distinguishable based on both morphology and molecular data (Hrivniak et al 2017(Hrivniak et al , 2019(Hrivniak et al , 2020a. Additionally, Hrivniak et al (2020b) identified seven other distinct lineages based on molecular data only.…”

“…Some species are local endemics to the Greater Caucasus, Pontic, Zagros, or Alborz Mountains. Others are widely distributed throughout the Caucasus and the adjacent areas of Anatolia, Cyprus, Iran, and Iraq (Hrivniak et al 2017(Hrivniak et al , 2019(Hrivniak et al , 2020a. Their distribution and diversity patterns can be explained by geological and climatic history, and land development in the region that have significantly affected the diversification of Caucasiron in the Caucasus (Hrivniak et al 2020b).…”