Eurylophella karelica Tiensuu, 1935 (Insecta: Ephemeroptera: Ephemerellidae) – an additional species to the mayfly fauna of Ukraine and notes on distribution of the family in the country

A rare European species, Eurylophella karelica Tiensuu, 1935 (Ephemeroptera: Ephemerellidae) is reported for the first time from Ukraine. The larvae of the species were found within Ukrainian Polissya region in the Pripyat’ River basin. Species list of family Ephemerellidae of Ukraine with notes on species distribution within the country is given in the present contribution.


PLATINUM OPEN ACCESS
Eurylophella Tiensuu, 1935 is a Holarctic genus encompassing 19 recent species. Most of these species inhabit the Neartcic realm, and only three of them occur within the western Palearctic region-Eurylophella karelica Tiensuu, 1935, E. iberica Keffermüller & Da Terra, 1978, and E. korneyevi Martynov, Palatov & Godunko, 2015(Martynov et al. 2015. Eurylophella karelica is the most common and widely distributed, the other two are rare with restricted distribution. Distribution of E. karelica extends from north to south, and falls within the north-west of the European part of Russia, Finland, Lithuania, Latvia, Estonia, Poland, Hungary, and Slovenia (Martynov et al. 2015;Ozoliņš et al. 2017). This species has not yet been recorded in Belarus (Moroz & Lipinskaya 2014), but it is likely to be found in the future.

Materials and Methods
The material was collected with square hydrobiological hand net 25cm long on each side. The sample is stored in 90-95 % ethanol in the author's collection in the National Museum of Natural History, National Academy of Sciences of Ukraine (Kyiv, Ukraine); its inventory number (IN) is Riv19Eurkar. Toponyms and hydronyms are duplicated in Ukrainian in square brackets.
Habitus of E. karelica larva was photographed using a Leica Z16 APO stereomicroscope equipped with Leica DFC450 Digital Camera in the I.I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, and was subsequently processed with LAS Core 3.8 and Adobe® Photoshop™ CS5 software. Material

Results and Discussion
In Ukraine, E. karelica was recorded at Polissya [Полісся] region in potamal zone of L'va [Льва] River J TT (Image 2) that belongs to Pripyat' [Прип'ять] River basin. This finding is the first record of E. karelica from Ukraine. The Pripyat' River basin, where the species was found, differs in the presence of a relatively large number of waterbodies, with slightly impaired species compositions of aquatic insects, in comparison with vast parts of lowland Ukraine. Thus, during investigation of Ephemeroptera at the Pripyat' River basin in 2017-2018 several stenobiotic and rare species were registered (Martynov 2018); some of these species had not yet been recorded elsewhere in Ukraine.

Habitat characteristics
The section of the L'va River, where E. karelica larvae were collected (Image 2, 3), is situated downstream of a dam. The river has moderate current velocity (up to 0.3m/s), but under the bridge and above the dam rapids with strong current are present (up to 1m/s). The bottom of the river is silty, sandy (in some places silted), and stony (under the bridge). All larvae of the species were collected from dead aquatic vegetation (leaves, stems etc.) in small bays with silted bottom and almost lacking flow (Image 2). The additional parameters of waterbody in collecting sites measured during the sampling (22. xii.2018) were: water temperature 6°C, water hardness 84ppm, pH 8.9.
The following mayflies were also collected within the investigated section of the L'va River in winter (

Ephemerellidae of Ukraine and their distribution within country
In the first checklist of mayflies of Ukraine, five species of subfamily Ephemerellinae were mentioned (Godunko & Kłonowska-Olejnik 2003). Eurylophella karelica, recorded for Ukraine for the first time herein, belongs to another subfamily -Timpanoginae. Thereby, now species list of Ephemerellidae of Ukraine consists of six species from five genera and two subfamilies, and E. karelica is the most rare species among them.  (Mikulski 1935;Godunko 2000;Godunko & Kłonowska-Olejnik 2003;Afanasyev 2006;Kovács & Godunko 2008). Such diversity is reasoned by abundance of waterbodies with unpolluted or moderately polluted rhithral and epipotamal zones preferred by a vast number of mayfly species.
Mayflies of Podolia and Volyn' [Волинська] Uplands, lowland, central, and southern regions of Ukraine are still poorly investigated. Most of the data are old and need confirmation due to significant changes and pollution levels in waterbodies, especially in central and southern regions.
The Crimean [Кримські] Mountains was investigated and summarized in detail (see overview in Prokopov & Godunko 2007). Only Serratella ignita was listed by Kiseleva & Yezernitskiy (1985) for this region, and there are no other mentions of the species for the Crimea [Крим]. According to Prokopov & Godunko (2007) the presence of this species in the fauna of the region needs confirmation.
Within physiographic regions of eastern Ukraine only one representative of Ephemerellidae-Serratella ignita-was registered. This species inhabits only rhithral and eupotamal zones of streams and headwaters of rivers within most elevated parts of Donetsk [Донецька] elevated areas, and the species is rare within it (Martynov 2014(Martynov , 2016. The recorded population of S. ignita is geographically isolated and should be considered as glacial relicts in this territory. It should be noted, that the diversity of Ephemerellidae in neighboring countries (Romania, Hungary, Slovakia, Poland, and European part of Russian Federation) does not exceed diversity of the family within Ukraine. The territory of Moldova is poorly investigated; two species of the family were recorded for Belarus only. Therefore, the Ephemerellidae species list given above should be considered as complete, and no other species of the family are expected to be registered in Ukraine in the near future. www.threatenedtaxa.org The Journal of Threatened Taxa (JoTT) is dedicated to building evidence for conservation globally by publishing peer-reviewed articles online every month at a reasonably rapid rate at www.threatenedtaxa.org. All articles published in JoTT are registered under Creative Commons Attribution 4.0 International License unless otherwise mentioned. JoTT allows allows unrestricted use, reproduction, and distribution of articles in any medium by providing adequate credit to the author(s) and the source of publication.