hear Fonozoo call (#1)
	hear Fonozoo call (#2)
	hear Fonozoo call (#3)

Description
Small stocky frog with relatively large head. Adults of both sexes obtain a snout-vent length of about 55 mm. The eyes are large and have a vertical slit-shaped pupil. Parotid glands are small, and the tympanum is mostly visible. The skin is warty, and a row of large, often reddish warts extends from the tympanum to the loin area. Other large gland complexes are present on the underarms and the ankles. There are three metacarpal tubercles. The coloration can vary from small black dots, brown dots to olive or green spots. The underside is a dirty white, and the throat and the chest are often spotted with gray (Noellert and Noellert 1992).

Males are somewhat smaller than females. Other features that distinguish males and females are: distance between nostrils, distance between the anterior end of the middle metacarpal tubercle and the tip of the third finger, and the distance from the elbow to the third finger tip. These variables should be corrected for the size of the animal (Bosch and Marquez 1996).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Belgium, France, Germany, Italy, Luxembourg, Netherlands, Portugal, Spain, Switzerland. Introduced: United Kingdom.

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (985 records).

This animal occurs in eight European countries: Portugal, Spain, France, Belgium, The Netherlands, Luxembourg, Germany and Switzerland. There are three European subspecies. A. o. obstetricans occurs north of the Pyrenees, A. o. almogavarii between the Pyrenees and the Ebro river and A. o. boscai south of the Ebro river. Another subspecies, A. o. maurus Pasteur & Bons, 1962, is endemic in the Rif mountains in Morocco. The species is present practically throughout France, with the exception of the higher part of the Alps. A. obstetricans shows a very clearly marked distribution limit between the mountainous and hilly regions of Central Europe which are inhabited, and the large plain to the North Sea, where the species is absent. For this reason, it cannot be found along the coast of Belgium, and in most part of the Netherlands (only in the hilly South Limburg). The northernmost population is found south of Hannover, in lower Saxony, the easternmost population in Northern and Central Germany (hilly regions of Thüringen and Harz). In Southern Germany the species only occurs in Baden-Württemberg in the region of the Black Forest. Switzerland is inhabited mainly in the Jura, in the central plain up to the Rhine, and in some parts of the northern slope of the Alps, though here only locally.

The water habitat varies greatly: not only all types of pools and ponds are used, but also not too fast running creeks (mainly in Iberia) and rivers. A. obstetricans prefers permanent waters, because larvae often over winter in water. The land habitat is just as important as the breeding sites: slopes, walls, embankments with many small stones, stone slabs or sand, normally with sparse vegetation are preferred. Larger colonies are observed in gravel or clay pits. Often the exposition is south, southwest or southeast and well exposed to the sun. The microclimate in the hiding places must be warm and humid.

In the Iberian Peninsula A. obstetricans occurs from the sea shore (e.g. in Asturias and Basque Country) up to 1960 m (in Portugal) and 2400 m in the Pyrenees. In the Alps, populations can be found up to 1670 m in the Bernese Oberland. In Central Europe, most populations live at altitudes between 200 and 700 m, rarely below 200 m (Gasc 1997).

Life History, Abundance, Activity, and Special Behaviors
These frogs are well known for their male parental care behavior. The males attach the egg masses to their body and carry them until the eggs hatch, at this point the males release the tadpoles into bodies of water. The females can produce up to four clutches of eggs per breeding season. Mating season varies throughout the range. In Westfalen, Germany, one can find males carrying eggs between the end of March, and the beginning of August. Around the city of La Coruña, males with clutches of eggs were observed from mid-February until August. In mountain populations most males carry eggs well into August.

Although males call mainly by night, they are known to call from their hiding places during the daytime. The call is a high-pitched, explosive, musical "poo...poo…poo…", about one call every 1-3 sec, usually higher and shorter than Bombina. The female seeks out the male and presents herself to him. The male grabs the female in the lumbar region. The male stimulates the females cloacal region by scratching it with its toes. After about 35 minutes, the male suddenly constricts the female's flanks. She extends her hind legs and ejects an egg mass. The male then releases his lumbar grip, takes an axillar hold and inseminates the eggs with a quantity of liquid sperm mass. After 10-15 minutes, the male distends the egg mass with his hind legs, piles them alternatingly to his body and extends them again until the strings of eggs are wound around his ankles. A male can copulate anew and carry up to three clutches around his legs with a total of 150 eggs or more (Schleich 1996).

Males keep the egg mass moist by microhabitat choice, or by taking short baths. Larvae hatch after 3 to 6 weeks. The males seek out small water bodies to discard the egg strings with the hatching larvae. Upon hatching, the larvae are about 15 mm and metamorphose the next year, when they have reached a maximum length of 5 to 8 cm (Engelmann et al 1985).

Trends and Threats
Populations of this species are threatened, especially on the northern border of its distribution. These populations suffer from the disturbance caused by the release of fish in their breeding waters (Noellert and Noellert 1992). Populations along the northern border, e.g., in Limburg, eastern Germany, in the Black Forest and western and central parts of the Swiss range, have disappeared for no obvious reason. The disappearance is likely to be disease-related, as this species is susceptible to chytridiomycosis (Bosch et al. 2001). In 1997, 1998, and 1999, mass die-offs of post-metamorphic A. obstetricans occurred in Spain, and dead frogs were found to have chytrid infections (Bosch et al. 2001). Habitat loss is also a factor in the decline of this species; in addition to outright habitat destruction, changes affecting the microclimatic conditions (e.g., drainage) have had a negative impact on A. obstetricans (Gasc 1997).

Possible reasons for amphibian decline

General habitat alteration and loss
Drainage of habitat
Predators (natural or introduced)
Disease

Comments

This species was featured as News of the Week on 23 May 2022:

Habitat loss or modification is the biggest threat to amphibians, which includes the introduction of non-native plants. Eucalyptus globulus trees have been introduced globally from its native Australia, and its negative effects on native species, including adult amphibians, have been documented. What about other stages? Iglesias-Carrasco et al. (2022) investigated with experiments on the effects of eucalypt leachates on tadpole behavior, morphology, growth, and immune response. Rana temporaria, Alytes obstetricans, and Pelophylax perezi tadpoles were raised in mesocosms with either native oak or exotic eucalypt leachates then exposed to predator cues. The authors found that while anti-predator responses were not significantly affected, tadpoles raised in eucalypt leachates were smaller and had weaker immune responses. Furthermore, the morphology of P. perezi tadpoles in eucalypt treatments were similar to the stress morphology of other species, which may affect the tadpoles’ ability to escape predators and jump in later development. Although species varied in responses, these results indicate that the poor nutrient content and high toxicity of Eucalyptus have strong impacts at critical early stages of frog development. Further studies are needed to fully understand the long-term fitness consequences of Eucalyptus monocultures. (Written by Ann Chang)

References

Bosch, J. and Marquez, R. (1996). ''Discriminant functions for the sex identification in two midwife toads (Alytes obstetricans and A. cisternasii).'' Herpetological Journal, 6, 105-109.

Bosch, J., Martinez-Solano, I., and García-París, M. (2001). ''Evidence of a chytrid fungus infection involved in the decline of the common midwife toad (Alytes obstetricans) in protected areas of central Spain.'' Biological Conservation, 97(3), 331-337.

Engelmann, W.-E., Guenter, R., and Obst, F. J. (1985). Lurche und Kriechtiere Europas. Neumann Verlag, Leipzig.

Gasc, J.-P. (1997). Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica, Bonn, Germany.

Nöllert, A. and Nöllert, C. (1992). Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stuttgart.

Pennisi, E. (2009). ''The case of the midwife toad: fraud or epigenetics?'' Science, 325(5945), 1194-1195.

Schleich, H. H., Kastle, W., and Kabisch, K. (1996). Amphibians and Reptiles of North Africa. Koeltz Scientific Publishers, Koenigstein.

Stumpel-Rieks, S. E. (1992). Nomina Herpetofaunae Europaeae. AULA-Verlag, Wiesbaden.

Vargas, A. O. (2009). ''Did Paul Kammerer discover epigenetic inheritance? a modern look at the controversial midwife toad experiments.'' Journal of Experimental Zoology Part B (Molecular Development and Evolution), 312B, 667-678.

Wagner, G. P. (2009). ''Paul Kammerer’s midwife toads: about the reliability of experiments and our ability to make sense of them.'' Journal of Experimental Zoology Part B (Molecular Development and Evolution), 312B, 665-666.

Species Account Citation: AmphibiaWeb 2022 Alytes obstetricans: Midwife Toad <https://amphibiaweb.org/species/1522> University of California, Berkeley, CA, USA. Accessed Jun 2, 2023.

Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 2 Jun 2023.

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