The foundations of Bulgarian herpetology (the study of amphibians and reptiles) were laid in the end of the 19th century by the teacher Vasil Kovachev, who published a number of articles on the subject and the 1912 book Herpetologic Fauna of Bulgaria.[5] In the 1930s and 1940s zoologist Ivan Buresh and his associate Yordan Tsonkov conducted in-depth research on the diversity and distribution of the amphibian and reptile species in the country. In the second half of the 20th century the leading Bulgarian herpetologist was Dr. Vladimir Beshkov.[5]
Salamandridae, or true salamanders, are a family of terrestrial and aquatic salamanders, mostly distributed in Asia and Europe, although some species are found in North Africa and North America. Most species have slightly toxic skin secretions and many develop dorsal body and tail fins when they return to an aquatic stage. There are 109 species in 21 genera; of these, nine species in four genera are found in Bulgaria.[9]
Found in the whole country, up to 1500 m altitude;[10] a 2017 study determined that the smooth newt was a species complex and was split in six species; the smooth newt sensu lato inhabits the north and west of the country[4]
Bombinatoridae are an Old World toad family often referred to as fire-bellied toads because of their brightly coloured ventral sides which demonstrate their high toxicity. It includes ten species in two genera, Barbourula and Bombina, both of which have flattened bodies, of which two species from genus Bombina occur in Bulgaria.[21]
Bufonidae are a family of toads native to every continent except Australia and Antarctica. Bufonidae include the typical toads with shortened forelimbs, hindlimbs used for walking or hopping, dry warty skin, and parotoid glands behind eyes. The family contains 590 species in 50 genera, of which 2 species from genus Bufo are found in Bulgaria.[26]
Hylidae or tree frogs are the most diverse amphibian family with 951 species in 51 genera, and worldwide distribution. Most species inhabit tropical areas with warm and humid climate, especially the Neotropics. Hylids range from small to large in size and usually have distinct adhesive toe discs that contain a cartilage offsetting the terminal phalanx, which aids in climbing. The only genus found in Europe is Hyla, with 6 species out of 37 worldwide, and one in Bulgaria.[31]
Pelobatidae, also known as spadefoot toads, are a small family of frogs with one genus and four species spread in Europe, Western Asia and North-western Africa. They have short legs, stocky bodies with vertical pupils and produce an odour similar to garlic, hence their name in Bulgarian is чесновица (chesnovica), 'garlic toad'. Two of the four species inhabit the country.[34]
Ranidae are a widespread family also known as true frogs. They have generalized frog body plans and a generalized aquatic tadpole stage. The family includes 379 species in 14 genera, of which six species in two genera occur in Bulgaria.[34]
^Tzankov, Nikolay; Stoyanov, Andrei (2008). "Triturus cristatus (Laurenti, 1768): a new species for Bulgaria from its southernmost localities". Salamandra. ISSN0036-3375.
Biserkov, V. (2007). Определител на земноводните и влечугите в България (A Field Guide to Amphibians and Reptiles of Bulgaria) (in Bulgarian). София (Sofia): Зелени Балкани (Green Balkans). ISBN978-954-9433-07-4.
Beshkov, Vladimir; Nanev, Krastyo (2002). Земноводни и влечуги в България (Amphibians and Reptiles of Bulgaria) (in Bulgarian). София (Sofia): Пенсофт (Pensoft). ISBN978-954-642-147-0.
Дончев (Donchev), Дончо (Doncho); Каракашев (Karakashev), Христо (Hristo) (2004). Теми по физическа и социално-икономическа география на България (Topics on Physical and Social-Economic Geography of Bulgaria) (in Bulgarian). София (Sofia): Ciela. ISBN978-954-649-717-8.