The edible frog (''Pelophylax'' kl. ''esculentus'') is a hybrid species of common European

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

, also known as the common water frog or green frog (however, this latter term is also used for the North American species ''

Rana clamitans ''Lithobates clamitans'' or ''Rana clamitans'', commonly known as the green frog, is a species of frog native to eastern North America. The two subspecies are the bronze frog and the northern green frog. These frogs, as described by their name, ...

''). It is used for food, particularly in France as well as Germany and Italy, for the delicacy

frog legs Frog legs () are the muscular hindlimbs of frogs that are consumed as food by humans in some cuisines. Frog legs are rich in protein, omega-3 fatty acids, vitamin A, and potassium. They are often said to taste like chicken because of the mild fl ...

. Females are between long, males between . This widespread and common frog has many common names, including European dark-spotted frog, European black-spotted pond frog, and European black-spotted frog.

Distribution

''Pelophylax esculentus'' is endemic to Europe. It naturally occurs from the northern half of France to western Russia, and from Estonia and Denmark to Bulgaria and northern Italy. The edible frog is introduced in Spain, Norway and the United Kingdom. The natural range is nearly identical to that of '' P. lessonae''.

Hybridogenesis

''Pelophylax'' kl. ''esculentus'' is the fertile hybrid 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 ...

(''Pelophylax ridibundus''). It reproduces by hybridogenesis (hemiclonally). Hybridogenesis implies that during

gametogenesis Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes. Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic d ...

hybrids (of RL

genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...

) exclude one parental genome (L or R) and produce

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

s with an unrecombined

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

of the other parental species (R or L, respectively), instead of containing mixed recombined parental genomes. The hybrid populations are usually propagated by mating ( backcrosses) with a

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

parental species – ''P. lessonae'' (LL) or ''P. ridibundus'' (RR) – providing the second, discarded parental genome (L or R respectively). Hybridogenesis is thus a hemiclonal mode of reproduction; half of the genome is transmitted to the next generation clonally, unrecombined (intact); the other half sexually, recombined. For example, in the most widespread so called L–E system, edible frogs ''Pelophylax'' kl. ''esculentus'' (RE) produce gametes of the marsh frog ''P. ridibundus'' (R) and mate with coexisting pool frogs ''Pelophylax lessonae'' (L gametes) – see below in the middle. Hybridogenesis in water frogs

Because this hybrid requires another taxon as a sexual host to reproduce, usually one of the parental species, it is a klepton, hence the addition of the "kl." (for ''klepton'') in the species name. There are also known all-hybrid populations, where

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

hybrids (LR) coexist with

triploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

(LLR or LRR) hybrids, providing L or R genomes respectively. In this situation, diploid hybrids (LR) generate not only haploid R or L gametes, but also the diploid gametes (RL) needed to recreate triploids. File:Rana-esculenta swimming 331.jpg, Swimming frog File:Rana-esculenta mating 325.jpg, Attempted copulation between two males File:Teichfrosch isst teichfrosch.JPG, Example of cannibalism File:Waterfrog head.jpg, Close-up of head File:Rana esculenta on nymphaea front view.JPG, Head close-up, another perspective File:Veekonn.JPG, Edible frog on a human arm File:Pelophylax esculentus 002.jpg, Edible frog in pond habitat File:Edible frog (Pelophylax esculentus).jpg, Edible frog in a swamp File:Larva of Edible frog.jpg,

Tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

References

External links

ArchéoZooThèque : Edible frog skeleton drawing

Species account on HerpFrance.com

Video: Pool frogs and hybrid green frogs
on

YouTube YouTube is an American social media and online video sharing platform owned by Google. YouTube was founded on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim who were three former employees of PayPal. Headquartered in ...

. Mixed mating of pool frog and edible frog; pool frog are grass green and smaller. {{Authority control Amphibia hybrids Amphibians of Europe Pelophylax Amphibians described in 1758 Taxa named by Carl Linnaeus Habitats Directive species