"Temporary Ponds: a natural habitat to be protected!"

Amphibians

> Iberian Spadefoot Toad

Pelobates cultripes


They are relatively large frogs, with a robust appearance, which generally measure between 5 and 8 cm, being able to reach 10 cm. They have a flattened head with a rounded nose and large, prominent "cat" eyes, that is, with the vertical pupil and silvery, gold or light iris with dark pigmentation. The parotid glands and vocal sacs are absent, and the eardrum is imperceptible.

Pelobates cultripes buried - Photo of Vasco Flores Cruz in Anfíbios e Répteis de Portugal

They have the hind limbs with four fingers and the anterior ones with five being connected by the well developed interdigital membranes. The great curiosity of this species is at the origin of its name, the black nail frog (in portuguese). This black nail is a metatarsal tubercle in the hind limbs that is very well developed, as shown in the following image, which helps the animal to quickly dig the soil to bury itself in it.

The Balck nail in Pelobates cultripes - Photo of Vasco Flores Cruz in Anfíbios e Répteis de Portugal

The dorsal coloration has a pattern of large dark spots and brown spots. In contrast, the belly is whitish or yellowish.

Sexual Dimorphism

Females appear to achieve a larger body size than males.

Behaviour

It has strictly nocturnal habits, spending the day buried in holes that it dig with the strong black nails of the hind limbs. In this geographical area of its distribution, further south, the species is active throughout the year and can take a summer break in the warmer summer months.

Reproduction

Its reproduction period is strongly dependent on climatic conditions, in particular the occurrence of precipitation. In general, this period occurs between mid-autumn to spring. In the meantime, this species shows a great ability to adjust breeding season and larval stage duration to the availability of water in their preferred aquatic habitats.

In order to reproduce, these frogs look for temporary ponds, usually in areas with little vegetation, shallow depth and sandy bottoms and where there are not many aquatic macro invertebrate predators.

Adults come to the ponds after dark and concentrate here throughout the mating season (about 35-45 days). Usually the first to arrive are the males. In mating season, the males' croaking reminds them of the slow cackling of chickens. Females, who usually arrive later to these breeding sites, may respond with similar sounds.

Cortesia de Versicolora

 The amplexus is inguinal, and may occur inside water or on the margins of the pond.

Amplexo de Pelobates cultripes - Fotografia de Vasco Flores Cruz em Anfíbios e répteis de Portugal

Females lay down between 1000 and 7000 eggs, arranged in a long thick gelatinous cord, which attaches to aquatic plants or falls to the bottom of the pond. Hatching occurs 7 to 15 days after laying, but tadpoles require three to four months to fully complete their development.

Tadpole of Pelobates cultripes - Photo of Vasco Flores Cruz in Anfíbios e Répteis de Portugal

Detail of the black nail in the tadpole of Pelobates cultripes - Photo of Vasco Flores Cruz in Anfíbios e Répteis de Portugal

The newly metamorphosed individuals generally measure about 2 to 3.5 cm of head-to-body length, being the Portuguese anurans of those who leave the water with larger size.

Sexual maturity is reached by the age of 3 and usually its longevity is about 10 years.

Feeding

Their food consists essentially of beetles, slugs, ants, earthworms, grasshoppers, butterflies, mosquitoes and insect larvae. Tadpoles feed mainly on plant remains, fungi and debris.

Its main predators are water snakes, various birds and some mammals. Tadpoles are consumed by various animals, fish, water snakes, dragonfly larvae and aquatic beetles.

In danger, they can bury themselves quickly by lateral movements of the hind legs (where the black nail is), or swell the body and emit intense sounds.

It is found in open areas of heathland or in arable plains, especially in flooded land, in the banks of temporary ponds and small lagoons.

It also colonizes reservoirs, flooded ditches and other marginal environments, such as abandoned quarries. 

 

It is a fairly common toad in the open Mediterranean regions of the Iberian Peninsula and the South of France. It is found mainly in places with little compacted soil, which allows it to be buried without difficulty. Thus, it occupies wooded spots, open ridges, pine forests, meadows, grasslands, pastures, vineyards, olive groves, cultivation terms, marshy areas, sand and dunes.

However, according to the IUCN, the population trend is declining because of the high fragmentation.

 Beja, P., Bosch, J., Tejedo, M., Lizana, M., Martinez Solano, I., Salvador, A., García París, M., Recuero Gil, E., Pérez Mellado, V., Díaz-Paniagua, C., Cheylan, M., Márquez, R. & Geniez, P. 2009. Pelobates cultripes. (errata version published in 2016) The IUCN Red List of Threatened Species 2009: e.T58052A86242868. Downloaded on 09 December 2016.

 

It is a very vulnerable species to run over on roads that interrupt migration routes between favorable habitats. On the other hand, the introduction of exotic species such as Louisiana red crayfish, Procambarus clarkii, may affect its breeding success since this species selects, preferably, habitats without large aquatic predators, and its distribution is negatively affected by its (Amphibian Atlas and Reptiles of Portugal).

This species has the Near-Threatened Conservation status, according to the IUCN Red List of the International Union for the Conservation of Nature and Natural Resources.


Beja, P., Bosch, J., Tejedo, M., Lizana, M., Martinez Solano, I., Salvador, A., García París, M., Recuero Gil, E., Pérez Mellado, V., Díaz-Paniagua, C., Cheylan, M., Márquez, R. & Geniez, P. 2009. Pelobates cultripes. (errata version published in 2016) The IUCN Red List of Threatened Species 2009: e.T58052A86242868. Downloaded on 09 December 2016.


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