Betic midwife toad
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Order: Anura
Family: Alytidae
The Alytidae family comprises 11 species in two genera, which are commonly referred to as the “midwife toads” (genus: Alytes) and the “painted frogs” (genus: Discoglossus). Overall, this family is now named after the midwife toads, in reference to the extraordinary level of parental care by the males in the family’s component genus Alytes – they carry strings of eggs wrapped around their hind legs for a month or more, keeping them protected and moist until they are ready to hatch. The Alytidae are an ancient family found throughout Europe, the Middle East and northwestern Africa. They diverged from all other amphibians about 210 millions years ago at the end of the Triassic period, which is around the same time that the first primitive mammals started to appear. The midwife toad family therefore evolved at the feet of some of the earliest dinosaurs, and survived the dinosaur’s demise nearly 150 million years later.
The midwife toad family are present in a small sub group of the Anura or “frogs and toads” which contains all of the most ancient families. This sub group (also called the Archaeobatrachia) comprises less than 7% of all of the frogs and toads, including some of the most evolutionarily distinct amphibian species. The family name of the midwife toads was formerly Dicroglossidae or “disc-tongued frogs” because, unlike the relatively slender tongues of many amphibians, midwife toads and painted toads possess a round and flattened tongue. Aside from their highly unusual breeding behaviour, midwife toads are also known to have a powerful defense mechanism against potential predators. They have warts on their back that produce a strong-smelling toxin when the toad is threatened, and a midwife toad’s poison can kill an adder (a venomous snake) in a matter of hours. Within the family Alytidae, the midwife toads diverged from their closest relatives, the painted frogs, about 155 million years ago, which is about 5 million years before the first birds started to appear in the fossil record. Midwife toads are therefore more different from their closest relatives than kangaroos are from elephants, as they started to evolve independently about 10 million years before the common ancestor of these two mammal groups. There are just 5 species of midwife toad surviving today, all in Europe.
The midwife toad family are present in a small sub group of the Anura or “frogs and toads” which contains all of the most ancient families. This sub group (also called the Archaeobatrachia) comprises less than 7% of all of the frogs and toads, including some of the most evolutionarily distinct amphibian species. The family name of the midwife toads was formerly Dicroglossidae or “disc-tongued frogs” because, unlike the relatively slender tongues of many amphibians, midwife toads and painted toads possess a round and flattened tongue. Aside from their highly unusual breeding behaviour, midwife toads are also known to have a powerful defense mechanism against potential predators. They have warts on their back that produce a strong-smelling toxin when the toad is threatened, and a midwife toad’s poison can kill an adder (a venomous snake) in a matter of hours. Within the family Alytidae, the midwife toads diverged from their closest relatives, the painted frogs, about 155 million years ago, which is about 5 million years before the first birds started to appear in the fossil record. Midwife toads are therefore more different from their closest relatives than kangaroos are from elephants, as they started to evolve independently about 10 million years before the common ancestor of these two mammal groups. There are just 5 species of midwife toad surviving today, all in Europe.
The Betic midwife toad is a small species, measuring around 35 mm in total length. The eyes are large and have a vertical slit-shaped pupil. The limbs are relatively long, as are the fingers and toes, which are unwebbed. The skin is fairly smooth and shiny, although some larger warts are present along the sides of the back. Raised glands present on the back on the head behind each eye (the “parotid” glands) are short and slim, but well marked. Red-orange glandular spots, as present in other midwife toad species, are absent. There is a marked line of white glandular warts running along the sides of the body. Background colouration of the toad is back grey, with many gray and blackish fine dots equally mixed with pale ones, which lends this species a "dusty" appearance. A marked grey zone is present between the eyes.
Midwife toads display remarkable and very unusual breeding behaviour, which is common to all member of the genus Alytes. Male midwife toads usually live in a hole in the ground that is reasonably damp and within a short distance of a water source. They make short, peeping calls to alert females to their presence. When a gravid (egg-bearing) female come to visit, the males embraces her firmly until she starts to produce her eggs, which occur in a long string like in all species of midwife toad. As they emerge, the male releases his grip of the female and crouches over the eggs releasing his sperm to fertilise them. After about a quarter of an hour, the male then slides forward on top of the female, reaches around her throat and, through a complicated set of movements, wraps the egg strings around his hind legs. When the male succeeds in wrapping the egg string securely around his hind legs, the female departs, leaving the male to care for the eggs until they hatch.
Male Betic midwife toads may add eggs strings from other females to their collection as the breeding season continues. They may keep the eggs wrapped around their hind legs for a month or more, protecting them from predation and preventing their desiccation. Although the males shelter in damp refuges which keep the eggs moist, they will also occasionally make trips to pools of water to moisten the eggs further. The male then hides in a dark, damp refuges, such as in rock fissures or under stones near to water sources until the tadpoles are ready to hatch. Males may also use their front feet for burrowing into soft soil to create their damp refuge holes. The eggs and tadpoles are light sensitive. Increasing movement of the tadpoles inside the eggs stimulates the male to briefly move into water. Eggs may be deposited in permanent mountain streams, man-made reservoirs and cattle troughs. Depositing the eggs in water causes their spontaneous hatching, and the tadpoles continue the remainder of their development in water, which may take up to a year to mature into metamorphosed toadlets, passing one winter in the water. Almost all known breeding habitats are in human-modified water bodies.
The diet comprises beetles, crickets, flies, caterpillars, centipedes, and millipedes, and tadpoles feed on vegetable matter. They chew with tiny, horny teeth. Young toads eat smaller sizes of the same prey that the adults feed on. The back of the midwife toad is covered with small warts that give off a strong-smelling poison when the toad is handled or attacked. The poison is so powerful that the toad has few natural predators and it also helps to keep the eggs strings on the male's back safe from attack. The tadpoles do not possess the poison, and therefore fall prey to fish and insects. This species is shy, nocturnal (or night active) and hide in their refuges during the day, although individuals give away their presence by their ringing call.
Male Betic midwife toads may add eggs strings from other females to their collection as the breeding season continues. They may keep the eggs wrapped around their hind legs for a month or more, protecting them from predation and preventing their desiccation. Although the males shelter in damp refuges which keep the eggs moist, they will also occasionally make trips to pools of water to moisten the eggs further. The male then hides in a dark, damp refuges, such as in rock fissures or under stones near to water sources until the tadpoles are ready to hatch. Males may also use their front feet for burrowing into soft soil to create their damp refuge holes. The eggs and tadpoles are light sensitive. Increasing movement of the tadpoles inside the eggs stimulates the male to briefly move into water. Eggs may be deposited in permanent mountain streams, man-made reservoirs and cattle troughs. Depositing the eggs in water causes their spontaneous hatching, and the tadpoles continue the remainder of their development in water, which may take up to a year to mature into metamorphosed toadlets, passing one winter in the water. Almost all known breeding habitats are in human-modified water bodies.
The diet comprises beetles, crickets, flies, caterpillars, centipedes, and millipedes, and tadpoles feed on vegetable matter. They chew with tiny, horny teeth. Young toads eat smaller sizes of the same prey that the adults feed on. The back of the midwife toad is covered with small warts that give off a strong-smelling poison when the toad is handled or attacked. The poison is so powerful that the toad has few natural predators and it also helps to keep the eggs strings on the male's back safe from attack. The tadpoles do not possess the poison, and therefore fall prey to fish and insects. This species is shy, nocturnal (or night active) and hide in their refuges during the day, although individuals give away their presence by their ringing call.
Endemic to southeastern Spain, this species' distribution is limited to several mountain ranges, at an altitude of 700 to 2,000 metres above sea level, in pine forests, oak forests and open rocky landscapes. Adults are usually observed on eroded soils near water, or found under stones. The rocky substrate varies from slates and schist to limestone, and this species is most regularly associated with calciferous open and very rocky landscapes. The tadpoles develop in clear mountain streams and in man-made reservoirs that have water all year round, such as cattle troughs. The species is largely confined to valleys and populations are often isolated from one another.
This species is restricted to the mountains of southeastern Spain, including the Sierra Tejeda and Sierra Almijara (Provinces of Málaga and Granada), the Sierra de Gádor (province of Almería), the Sierra de Baza (province of Grenada), the Sierra Mágina (province of Jaén), and the Sierra de Alcaraz (province of Albacete). The populations are very fragmented (it has a small area of occupancy within its 30,769 km sq. range). It occurs at altitudes of between 700–2,140 metres above sea level (Sierra Nevada, Almería).
Populations of this species are highly fragmented, and many are confined to isolated mountains. Betic midwife toads are relatively common in the Alcaraz, Segura, and Cazorla mountains, but it is rare in drier mountains (Filabres, Baza, Gádor), where it is associated with springs. Populations in drier areas may consist of only a few adults.
The population of this species is thought to be declining by the IUCN Red List of Threatened Species.
The Betic midwife toad is listed as Vulnerable in the IUCN Red List of Threatened Species because its area of occupancy is less than 2,000 km sq., its distribution is severely fragmented, and there is a continuing decline in the extent and quality of its habitat and in the number of subpopulations.
This species is threatened by loss of suitable breeding habitat through excessive water withdrawal, droughts and the modernisation of agricultural practices leading to the abandonment of cattle troughs and other man-made water sources. The traditional water troughs provided good breeding habitat for this species, but the modern ones are inaccessible to this species, and drainage of habitat is also an issue. There may be an inherent threat associated with the isolated nature of the small Betic midwife toad populations, including the loss of genetic variation (necessary for the maintenance of a healthy population) and the risk to each group of environmental disasters and disease. A potential future threat is the fungal disease chytridiomycosis, which has already impacted the related midwife toad (Alytes obstetricans) in Spain.
The Betic midwife toad is listed on Appendix III of the Berne Convention, and in regional Red Data Books. It is present in the protected areas of Parque Nacional Sierra Morena, Parque Nacional de Sierra Nevada, and the Natural Park of Cazorla, Segura y las Villas. Protection measures in Castilla-La Mancha, Andalusia are underway, including the restoration and construction of new breeding habitats.
This project aims to identify which environmental and climatic factors are the main predictors for the presence of these species.
Scientists at the Museo Nacional de Ciencias Naturales in Madrid are montioring populations of this species for the fungal disease chytridiomycosis. This is an essential conservation measure that must continue because this disease has already been identified in closely related midwife toads of mainland Europe. Protecting the breeding habitat of this species is also a priority, as well as creating new breeding areas through the creation of ponds and refuges. Given the threat of virulent disease, the possibility of a captive breeding programme, like the one that has been successfully organised for the Mallorcan midwife toad, should be investigated. The Spanish Institute for Nature Conservation (ICONA) has also recognised the need for research into the factors impacting this species and commissioned a study to assess the conservation status of the Betic midwife toad. Lastly, an initiative focusing on moving individuals between isolated populations or connecting up the fragmented habitat of this species would be a positive contribution to its conservation. However, enormous care would have to be taken to ensure disease was not spread between different populations.
In addition, we recommend the creation of additional breeding habitat for this species in areas where modernised agricultural practices have reduced the number of accessible water-bodies used when the toad is breeding. The provision of artifiial refuges would also be of enormous benefit.
In addition, we recommend the creation of additional breeding habitat for this species in areas where modernised agricultural practices have reduced the number of accessible water-bodies used when the toad is breeding. The provision of artifiial refuges would also be of enormous benefit.
Jaime is an amphibian researcher and conservationist from Spain
Wouter is an undergraduate student studying amphibians.
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Márquez, R. and Bosch, J. 1996. Advertisement call of the midwife toad from the Sierras Béticas Alytes dickhilleni Arntzen & García-Paris, 1995 (Amphibia, Anura, Discoglossidae). Herpetological Journal 6(1): 9-14.
Martínez-Solano, I., Gonçalves, H.A., Arntzen, J.W. and García-París, M. 2004. Phylogenetic relationships and biogeography of midwife toads (Discoglossidae: Alytes). Journal of Biogeography 31(4): 603-618.
Martínez-Solano, I., París, M., Izquierdo, E. and García-París, M. 2003. Larval growth plasticity in wild populations of the betic midwife toad, Alytes dickhilleni (Anura: Discoglossidae). Herpetological Journal 13(2): 89-94.
Mattison, C. 1987. Frogs and toads of the world. Blandford Press, U.K.
Obst, F.J., Richter, K. and Jacob, U. 1984. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. T.F.H. Publication Inc., N.J., U.S.A.
Pleguezuelos, J.M. 1997. Distribucion y Biogeografia de los Anfibios y Reptiles en España y Portugal. Asociacion Herpetologica Española, Las Palmas de Gran Canarias.
Pleguezuelos, J.M., Márquez, R. and Lizana, M. 2002. Atlas y Libro Rojo de los Anfibios y Reptiles de España. Dirección General de la Conservación de la naturaleza-Associación Herpetológica Española, Madrid.
Roelants, K., Gower, D. J., Wilkinson, M., Loader, S. P., Biju, S. D., Guillaume, K., Moiau, L. and Bossuyt, F. 2007. Global patterns of diversification in the history of modern amphibians. Proceedings of the National Academy of Sciences 104: 887-892.
Arnold, E.N. 2003. Reptiles and amphibians of Europe. Princeton University Press, Princeton and Oxford.
Arntzen, J.W. and García-París, M. 1995. Morphological and allozyme studies of midwife toads (Genus Alytes), including the description of two new taxa from Spain. Contributions to Zoology 65(1): 5-34.
Behler, J.L. and Behler, D.A. 2005. Frogs: A Chorus of Colors. Sterling Publishing, NY, U.S.A.
Benavides, J., Viedma, A., Clivilles, J., Ortiz, A. and Gutiérrez, J.M. 2000. Albinismo en Altyes dickhilleni y Salamanadra salamandra en la Sierra de Castril (Granada). Boletín de la Asociación Herpetológica Española 11(2): 83.
Bosch, J., Tejedo, M., Lizana, M., Martínez-Solano, I., Salvador, A., García-París, M., Gil, E.R. & Arntzen, J.W. 2004. Alytes dickhilleni. In: IUCN 2006. 2006 IUCN Red List of Threatened Species.
Duellman, W. E. and Trueb, L. 1986. Biology of Amphibians. McGraw-Hill, New York.
Fromhage, L., Vences, M. and Veith, M. 2004. Testing alternative vicariance scenarios in Western Mediterranean discoglossid frogs. Molecular Phylogenetics and Evolution 31(1): 308-322.
Frost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006). Electronic Database accessible at:
Frost, D. R., Grant, T., Faivovich, J., Bain, R.H., Haas, A., Haddad, C. F. B., De Sá, R.O., Channing, A., Wilkinson, M., Donnellan, S.C., Raxworthy, C.J., Campbell, J.A., Blotto, B.L., Moler, P., Drewes, R.C., Nussbaum, R.A., Lynch, J.D., Green, D.M., and Wheeler, W.C. 2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1-370.
García-Cardenete, L., González de la Vega, J.P., Barnestein, J.A.M. and Pérez-Contreras, J. 2003. Consideraciones sobre los límites de distribución en altitud de anfibios y reptiles en la Cordillera Bética (España), y registros máximos para cada especie. Acta Granatense 2(3-4).
Gasc, J.-P. (ed.) 1997. Atlas of Amphibians and Reptiles in Europe. Societas Europea Herpetologica & Museum National d'Histoire Naturelle, Paris.
IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment.
Márquez, R. and Bosch, J. 1996. Advertisement call of the midwife toad from the Sierras Béticas Alytes dickhilleni Arntzen & García-Paris, 1995 (Amphibia, Anura, Discoglossidae). Herpetological Journal 6(1): 9-14.
Martínez-Solano, I., Gonçalves, H.A., Arntzen, J.W. and García-París, M. 2004. Phylogenetic relationships and biogeography of midwife toads (Discoglossidae: Alytes). Journal of Biogeography 31(4): 603-618.
Martínez-Solano, I., París, M., Izquierdo, E. and García-París, M. 2003. Larval growth plasticity in wild populations of the betic midwife toad, Alytes dickhilleni (Anura: Discoglossidae). Herpetological Journal 13(2): 89-94.
Mattison, C. 1987. Frogs and toads of the world. Blandford Press, U.K.
Obst, F.J., Richter, K. and Jacob, U. 1984. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. T.F.H. Publication Inc., N.J., U.S.A.
Pleguezuelos, J.M. 1997. Distribucion y Biogeografia de los Anfibios y Reptiles en España y Portugal. Asociacion Herpetologica Española, Las Palmas de Gran Canarias.
Pleguezuelos, J.M., Márquez, R. and Lizana, M. 2002. Atlas y Libro Rojo de los Anfibios y Reptiles de España. Dirección General de la Conservación de la naturaleza-Associación Herpetológica Española, Madrid.
Roelants, K., Gower, D. J., Wilkinson, M., Loader, S. P., Biju, S. D., Guillaume, K., Moiau, L. and Bossuyt, F. 2007. Global patterns of diversification in the history of modern amphibians. Proceedings of the National Academy of Sciences 104: 887-892.
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