The frogs in the pictures below are European water frogs from the genus Pelophylax.
The most well known species is the Pelophylax kl. esculentus, formerly Rana esculenta which is called the edible frog. But the edible frog is not actually an independent species but a hybrid of two distinct species: the pool frog (Pelophylax lessonae) and the marsh frog (Pelophylax ridibundus).
I can’t easily tell these species from each other as there are color variations even within the same species. Also there are a large number of species in the genus Pelophylax which I can’t tell from one another — I am not even sure how easy it is to identify which species an individual water frog is without a DNA test.
These frogs are fairly common all over Europe and in particular the hybrid edible frog is eaten as a delicacy especially in French cuisine as frog legs.
Pelophylax frogs are true frogs and were previously placed in the genus Rana which was later split up and Pelophylax frogs mentioned in this article were separated from their North American cousins which were placed in the genus Lithobates whose most well known member is the American bullfrog. As I keep saying, even taxonomists need to eat.
The biology of the edible frog is somewhat complex and puts the whole definition of what constitutes a species into even more question than it already is. Female edible frogs are fertile and they seem to produce eggs that are for practical purposes the same as marsh frog eggs. Thus an edible frog female spawning with a a male pool frog produces an offspring of edible frogs. The same female edible frog if she spawns with a marsh frog male produces a generation of marsh frogs.
Like their Lithobates cousins Pelophylax frogs like to eat everything in sight and will not shy away even from cannibalism.
It is possible to keep Pelophylax frogs as pets but it is somewhat unusual to do so. They do tend to jump a lot and hurt themselves in confined spaces.
Pool frog on Wikipedia.
Marsh frog on Wikipedia.
Pelophylax on Wikipedia.
Hybridogenesis in water frogs on Wikipedia.