Hipparchia fagi/syriaca complex
The species Hipparchia fagi and Hipparchia syriaca have been separated based on UNH.
See the analysis at http://www.pamperis.gr/THE_BUTTERFLIES_OF_GREECE/Morphometrics_of_Hipparchia_fagi_and_H._syriaca.html
If the yellow surface (1, 2, 3, 4) is much larger than the green surface (4, 5, 6, 7) then the species is Hipparchia syriaca.
If the yellow surface (1, 2, 3, 4) is approximately equal to or less than the green surface (4, 5, 6, 7) then the species is Hipparchia fagi.
But this criterion has been challenged. See details at https://royalsocietypublishing.org/doi/full/10.1098/rspb.2010.1089 and FigS19 and S20 in https://www.researchgate.net/publication/259077848_Annex_4/link/0c960529e3fa0d934a000000/download
Photographs and distribution maps (data 18 X 2020) for these two species are provided. In the islands of the eastern Aegean only Hipparchia syriaca exist (with the subspecies Hipparchia syriaca ghigii in Rhodes).
ABOVE: One male Hipparchia syriaca ghigii (Rhodes)
BELOW: One male and one female Hipparchia syriaca (Samos)
ABOVE: One male Hipparchia fagi
BELOW: One female Hipparchia fagi