1. In Pelobatidae......................................................................................................................................................2
— In other hosts........................................................................................................................................................3
2. Hamuli underdeveloped. Hamuli present as primordia with length of 15 μm, situated between FIrst pair of suckers and slightly anteriorly to marginal hooklets. Body length 6.574 (5.405 –8.378) mm, body width 2.285 (1.703 –2.756) mm. Near Lake Durankulak (Bulgaria). Parasite of common spadefoot, Pelobates fuscus...................................................................................... P. fuscus Biserkov & Hadjinikolova, 1993
— Hamuli developed................................................................................................................................................3
3. In Hylidae. Body length 3.4 (2.964 –4.275) mm, body width 1.4 (1.235 –1.651) mm. Hamuli (average): a 217, b 199, c 64, d 60 μm; ratio a/b 1.1, b/c 3.1, b/d 3.3. Parasite of common tree frog, Hyla arborea, Petrich (Bulgaria)................................................................................................ P. skrjabini Buchvarov, 1984
— In other hosts........................................................................................................................................................4
4. In Bufonidae. Body length 9.8 (8.9-10.8) mm. Hamuli (average): a 418, b 338, c 93, d 51μm; ratio a/b 1.1, b/c4.2, b/d 7.9. In Corsica (France), Plovdiv (Bulgaria), Kyiv, Kherson Region, Crimea (Ukraine); parasite of green toad, Bufotes viridis...................................... P. viridis Euzet, Combes, Batchvarov, 1974
— In Ranidae..............................................................................................................................................................5
5. Ratio of hamuli measurements a/b about 2.0. Ratios b/c 0.7, b/d 0.8. Slots between spines on basal end of the crown deep. Average body length 10.1, body width 3.4 mm. Hamuli (average): a 480, b 233, c 359, d 298 μm. Parasite of common frog, Rana temporaria, wide spread throughout the distribution area of the host........................................................................................................... P. integerrimum (Fröhlich, 1798)
— Ratio of hamuli measurements a/b much smaller than 2.0...........................................................................6
6. Slots between spines on basal end of the crown deep. A constriction part in the crown of the spines of copulatory organ is situated at 1/3 of the length of the spines, close to their dorsal ends. Ratio of hamuli measurements: a/b 1.5, b/c 0.9, b/d 2. In Western Poland and Lviv Region (Ukraine). Parasite of moor frog, Rana arvalis............................................................................................ P. scuratovitchi Buchvarov 1984
— Slots between spines on basal end of the crown spines of copulatory organ shallow. A constriction part in the crown of the spines of copulatory organ situated at 1/5 of the length of the spines, close to their dorsal ends. In Plovdiv, Razlog, Jahoruda and Guljna bania (Bulgaria); Yalova Province, Çinarcik County (Turkey); Lviv Region (Ukraine). Parasite of agile frog, Rana dalmatina................................................................................................................................................................ P. mazurmovici Buchvarov 1980