Pelophylax perezi (López-Seoane 1885)

Snout-vent length in this species is usually from 40 to 70 mm, but sometimes is longer than 10 cm (Docampo and Milagrosa-Vega 1988; González de la Vega 1988). The head is as long as wide, with prominent eyes located in dorsal position very close to each other. The tympanum is well marked, about 1/2 to 3/4 the eye diameter (Salvador and García-París 2001). Toes have well developed webbing. Skin is either smooth or slightly rough, with well-formed dorsolateral folds. The dorsal coloration is very variable, usually green but also brown or grayish to dark gray. They usually show a vertebral stripe, mostly yellow or green. Two irregular rows of dark, rectangular spots are present on both sides of the vertebral stripe. These spots are also present on the rear limbs, sometimes forming a banded pattern. Some individuals lack both the spots and the vertebral stripe. Ventrally they are white with a variable number of dark spots.Males are smaller than females and have stronger forelimbs. They have gray vocal sacs than can be appreciated even when they are not in use.Tadpoles grow up to 111 mm total length (Salvador 1985), but usually measure between 60-70 mm (Barbadillo et al. 1999). The spiracle is sinistral and the anus open on the right side of the base of the tail. Marginal papillae are absent from the upper side of the mouth. Denticles are arranged in a variable number of single rows (Llorente et al. 1994), but the most common formula is 2(2)/3(1). The dorsal fin is low, starting at the level of the spiracle. The tip of the tail is pointed. Ground coloration is green or light brown, with small, dark dots. These dots are denser and larger in the tail fin. The tail presents a typical pattern with three longitudinal dark stripes. The ventral coloration is white.In southern France and northeastern Spain is present Rana Kl. grafi Crochet, Dubois, Ohler and Tunner, 1995, the klepton associated with Rana perezi. This hybridogenetic species was originated by hybridization between Rana perezi and R. ridibunda (Graf et al. 1977; Uzzell and Tunner 1983; Arano et al. 1995).Go here (http://www.mma.es/conserv_nat/inventarios/inv_biodiversidad/html/anfibios_reptiles/Anfibios/ran_per.htm) to view a Spanish account for Rana iberica.References:Arano, B., Llorente, G., García-París, M. and Herrero, P. (1995). Species translocation menaces Iberian Waterfrogs. Conservation Biology, 9(1): 196-198. Barbadillo, L.J., Lacomba, J.I., Pérez Mellado, V., Sancho, V. and López-Jurado, L.F. (1999). Anfibios y reptiles de la Península Ibérica, Baleares y Canarias. GeoPlaneta S.A. Barcelona. 419 pp. Docampo, L. and Milagrosa-Vega, M. (1988). Aplicación de un método estadístico al dimorfismo sexual del crecimiento relativo de Rana perezi (Seoane, 1885). Cuadernos de Investigación Biológica, 13: 53-65. Esteban, M., García-París, M. and Castanet, J. (1996). Use of bone histology in estimating the age of frogs (Rana perezi) from a warm temperate climate area. Canadian Journal of Zoology, 74(10): 1914-1921. García-París, M. (1985). Los anfibios de España. Ministerio de Agricultura, Pesca y Alimentación. Madrid. 287 pp. García-París, M. (1997). Rana perezi Seoane, 1885. In: Atlas of amphibians and reptiles in Europe. Gasc, J. P., Cabela, A., Crnobrnja-Isailovic, J., Dolmen, D., Grossenbacher, K., Haffner, P., Lescure, P., Martens, H., Martínez-Rica, J.P., Maurin, H., Oliveira, M.E., Sofianidou, T.S., Veith, M. y Zuiderwijk, A. (Eds.). Societas Europaea Herpetologica et Muséum National d’Histoire Naturelle. Paris: 152-153. Godinho, R., Teixeira, J., Rebelo, R., Segurado, P., Loureiro, A., Álvares, F., Gomes, N., Cardoso, P., Camilo-Alves, C. and Brito, J.C. (1999). Atlas of the continental Portuguese herpetofauna: an assemblage of published and new data. Revista Española de Herpetología, 13: 61-81. González de la Vega, J.P. (1988). Anfibios y reptiles de la provincia de Huelva. ERTISA. Huelva. 237 pp. Graf, J. D., Karch, F. and Moreillo, M. C. (1977). Biochemical variation in the Rana esculenta complex: a new hybrid form related to Rana perezi and Rana ridibunda. Experientia, 33: 1582-1584. Llorente, G.A., Arano, B., García Serra, N. and Civantos, E. (1995). Extreme variability in the oral morphs of Rana perezi larvae: their dubious application in the diagnosis of the P-RP system. Revista Española de Herpetología, 9: 85-91. Llorente, G.A., Montori, A., Carretero, M.A. and Santos, X. (2002). Rana perezi, En: Atlas y libro rojo de los anfibios y reptiles de España. Pleguezuelos, J.M., Márquez, R. y Lizana, M. (Eds.). Dirección General de la Conservación de la Naturaleza-Asociación Herpetológica Española. Madrid: 126-128. Pleguezuelos, J. M., Márquez, R. and Lizana, M. (eds.) (2002). Atlas y Libro Rojo de los Anfibios y Reptiles de España. Dirección General de Conservación de la Naturaleza-Asociación Herpetológica Española (2ª impresión), Madrid, 587 pp. Salvador, A. and García-París, M. (2001). Anfibios Españoles. Canseco-Esfagnos. Talavera de la Reina. 269 pp. Uzzell, T. and Tunner, H. G. (1983). An inmunological analysis of Spanish and French water frogs. Journal of Herpetology, 17: 320-326. Wicherley, J., Doran, S. and Beebee, T. J. C. (2003). Tracing aliens: identification of introduced water frogs in Britain by male advertisement call characteristics. Herpetological Journal, 13 (1): 43-50.

The distribution of this species comprises the Iberian Peninsula and the south of France. The northern limit of its distribution is probably south to the Loire basin (Llorente et al. 2002), with known populations as north as La Vendée and Lyon (Garcia-París 1997). In the Iberian Peninsula is widely distributed both in Spain and Portugal (Godinho et al. 1999; Llorente et al. 2002), and can be found from sea level to elevations around 2000 meters. This frog has been introduced in Madeira, the Balearic and the Canary Islands (Garcia-Paris 1997). Wycherley et al. (2003) reports the existence of an introduced population of Rana perezi in a locality in England along with several other European species of the group.Rana perezi is present in a wide range of environmental conditions, but is conditioned by the existence of water masses, including man-made water reservoirs. They can use both lotic and lentic waters and can resist some degree of pollution and salinity (Barbadillo et al. 1999; Llorente et al. 2002).

In the coldest areas they can undergo a winter rest period of variable length, but in most of the range they can be found active all year round (García-París 1985; Salvador and García-París 2001). They have both diurnal and nocturnal activity, but in the summer months the diurnal activity is limited by the intensity of the sun radiation. Most of the activity takes place inside or by the water. The reproductive period is long and calls can be heard all year round depending on the areas (González de la Vega 1988; Esteban et al. 1996). Females can lay up to 7160 eggs (Salvador and García-París 2001). Eggs can be adhered to the vegetation and rocks but also can be found on the surface of the water. Hatching takes place in 5-8 days and metamorphosis usually in 8-12 weeks (González de la Vega 1988), but some tadpoles can spend the winter without metamorphosis. Males reach sexual maturity in 2-3 years and females in 2-3 years (Salvador and García-París 2001).The diet varies depending on availability of prey, as they are opportunistic predators. In general, Diptera, Coleoptera and Hymenoptera compose most part of their diet. They can predate occasionally on vertebrates, including small mammals. Some cases of cannibalism have been reported (Salvador and García-París 2001).

This is still a common species throughout its range. It can be affected by polution of water. In some agricultural areas the masive use of chemical products has derived in an alarming decline of the populations (Pleguezuelos et al. 2002). The disappearance of water bodies and droughts are additional problems for Rana perezi. It is also affected by the introduction of exotic species, especially others species of Rana that can hybridize with this species (Arano et al. 1995).

This species has been hunted traditionally for food in many places through its range. At the present time the consumption of legs of this species is more and more restricted, as the decline in the densities of frogs has reduced the profitability of this activity.