The pool frog (''Pelophylax lessonae'') is a

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

frog A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...

in the family Ranidae. Its specific name was chosen by the Italian herpetologist

Lorenzo Camerano Lorenzo Camerano (9 April 1856 Biella – 22 November 1917 Turin) was an Italian herpetologist and entomologist. Born in Biella in 1856 he studied in Bologna and Torino, where he settled in order to take, between 1871 and 1873, a painting cour ...

in 1882, in order to honour his master Michele Lessona.

Description

The pool frog is a small frog which rarely grows to more than 8 cm long, although females can grow up to 9 cm. Males are typically around 5 cm long, while females are around 6–6.5 cm long. These frogs are brown or green, with dark blotches along their backs, a pair of ridges running from each eye and a cream or yellow stripe down the middle of the frog's back. The

vocal sac The vocal sac is the flexible membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the vocal sac is one way o ...

s on the male are cream or even white.

Distribution

The pool frog is found across most of central Europe from the west coast of northern France to the Western part of Russia. There are also small populations of pool frogs in the United Kingdom, Spain, Sweden and Norway. Pool frogs were previously thought to be a non-native species in the UK, but studies have shown that English pool frogs are related to the Swedish and Norwegian populations. The pool frog is found in damp areas with dense vegetation, or in calm, slow flowing rivers, ponds, bogs or marshes. According to

Amphibiaweb AmphibiaWeb is an American non-profit website that provides information about amphibians. It is run by a group of universities working with the California Academy of Sciences: San Francisco State University, the University of California at Berke ...

populations of this frog survive in urban areas and even fisheries. The creation of new ponds and other bodies of water leads to increased dispersal and a growth in the population of these frogs.

Pool frogs in Britain

Pelophylax lessonae is one of only four

amphibian Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbor ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate ...

recognized by the UK government as protected under its Biodiversity Action Plan. The reasons for declining populations are decreased

pond A pond is an area filled with water, either natural or Artificiality, artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% Aquatic plant, emergent vegetation helps in disting ...

habitat from human encroachment and also air pollution leading to over-nitrification of pond waters. The pool frog has not always been recognised as a native British species. Part of the reason for this is that specimens are known to have been introduced from southern Europe (though not from Scandinavia). However research has now shown that the potentially native UK pool frogs are closely related to Scandinavian frogs, not to frogs from further south. A native origin is most likely. The Herpetological Conservation Trust website states that "The Pool Frog is a

and was formerly recorded from two sites in

East Anglia East Anglia is an area in the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire. The name derives from the Anglo-Saxon kingdom of the East Angles, a people whose name originated in Anglia, in w ...

although it was lost from one of these in the middle of the 19th century. It was presumed extinct in the wild at the last remaining site by 1995. A single individual known from this population survived in captivity until 1999. Other populations have become established in the UK and it is known that some of these included individuals of British origin in their founding stock." An

English Nature English Nature was the United Kingdom government agency that promoted the conservation of wildlife, geology and wild places throughout England between 1990 and 2006. It was a non-departmental public body funded by the Department for Environme ...

reintroduction project is underway in

Breckland Breckland in Norfolk and Suffolk is a 39,433 hectare Special Protection Area (SPA) under the European Union Directive on the Conservation of Wild Birds. The SPA partly overlaps the 7,544 hectare Breckland Special Area of Conservation. As a la ...

, where pool frogs were introduced to a single site in 2005. RanaLessonae1

Hybridogenesis

The

edible frog The edible frog (''Pelophylax'' kl. ''esculentus'') is a species of common European frog, also known as the common water frog or green frog (however, this latter term is also used for the North American species '' Rana clamitans''). It is used ...

''Pelophylax'' kl. ''esculentus'' is a hybridogenetic

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

of the pool frog ''Pelophylax lessonae'' and the

marsh frog The marsh frog (''Pelophylax ridibundus'') is a species of water frog native to Europe and parts of western Asia. Description The marsh frog is the largest type of frog in most of its range, with males growing to a size around 100 mm (3.9 ...

''P. ridibundus''. Its populations are maintained however through other crossings by hybridogenesis.

References

External links

BBC News article on the reintroduction
* ttps://www.youtube.com/watch?v=Vaw3OpTopcA Movie with sound Youtube {{Taxonbar, from=Q754058 Pelophylax Amphibians of Europe Amphibians described in 1882 Taxa named by Lorenzo Camerano