Iberian midwife toad (Alytes cisternasii)

Description

Iberian midwife toad fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Iberian midwife toad description

A squat, rough-skinned amphibian ⁽³⁾, the Iberian midwife toad (Alytes cisternasii) belongs to an ancient family which diverged from all other amphibians around 210 million years ago ⁽⁴⁾. It has a small, stocky body with a short head and large eyes, which have vertical, slit-shaped pupils ^{(2) (4)}. One or two rows of small, usually reddish warts are present on the upper eyelids ⁽²⁾.

The Iberian midwife toad is generally brown on the upperparts, with dark spots and red warts. The underparts are whitish, and there is often a light-coloured band between the eyes ⁽²⁾. A row of large warts extends from the tympanum, which is clearly visible, to the groin ^{(2) (4)}. Large glands are also present under the arms and on the ankles ⁽²⁾. The fingers of the Iberian midwife toad are short and unwebbed, while the toes are long and webbed at the base ⁽⁴⁾. The male Iberian midwife toad is smaller than the female ⁽²⁾.

The call of the male Iberian midwife toad is a short, pure tone, given at relatively long, regular intervals. Unlike many other amphibians, the female will approach the male and emit softer calls before proceeding to engage in a duet with the male ⁽⁵⁾.

Spanish

Sapo Partero Ibérico.

Size

Male snout-vent length: up to 3.6 cm ⁽²⁾

Female snout-vent length: up to 4.2 cm ⁽²⁾

Iberian midwife toad biology

A nocturnal and largely terrestrial amphibian ^{(3) (4) (6)}, the Iberian midwife toad lives most of its life away from water. This species spends a large amount of time underground and is known to dig and bury itself in sandy soil to avoid drying out. It is a particularly efficient burrower, using its forelimbs to excavate soil and its head to scoop the debris out of the way ⁽⁴⁾.

The breeding season of the Iberian midwife toad occurs between September and March, with a peak in breeding activity around October and November ⁽²⁾. The male advertises for a mate by calling for several hours a night throughout the breeding season ^{(2) (4)}. The female will respond to the vocalisations of the male by calling back in reply ^{(2) (4) (7)}, a behaviour which is fairly unusual among most frogs and toads ^{(4) (7)}. The Iberian midwife toad is not usually territorial, although some non-aggressive competition between males for access to females does occur ^{(4) (7)}.

The male and female Iberian midwife toad may call with one another for several minutes before going into amplexus ⁽⁷⁾. The female seeks out the male, who will then grab the female by the waist ^{(2) (3) (4) (5)}. The female responds with a side-to-side rocking motion of the body ⁽²⁾. The male will then squeeze the female’s sides, causing the release of a string of up to 100 eggs into a cup-shaped receptacle, which is formed by the female bending the legs, pressing the heels together and holding them against the body. The eggs are fertilised by the male ^{(4) (5)}.

This species is highly unusual in that the male provides most of the parental care ⁽⁴⁾. Following amplexus, the male Iberian midwife toad will move its back legs through the string of eggs, winding them around the legs and ankles. The eggs are carried in this position for around three to five weeks, during which time they are protected by the male and kept moist until they are ready to be returned to water to hatch into tadpoles ^{(3) (4) (6) (7) (8)}.

The female Iberian midwife toad may produce up to four clutches of eggs during the breeding season ⁽²⁾. The male frequently mates with more than one female, and is able to carry up to four strings of eggs wrapped around its legs ^{(2) (4) (5)}. This species becomes sexually mature at around two years old ^{(2) (4)}. 

As well as its unusual breeding behaviour, the Iberian midwife toad is also unusual among amphibians in having a powerful defence mechanism against predators. Like other members of its family, this species produces a potent, strong-smelling toxin from the warts on its back when threatened ⁽⁴⁾.  

Iberian midwife toad range

The Iberian midwife toad is endemic to the Iberian Peninsula, where it occurs in southern and eastern Portugal and western and central Spain ^{(1) (2) (4)}. Although it is locally common in areas of suitable habitat, the Iberian midwife toad is generally more abundant in the western parts of its range ⁽¹⁾.

This species may be found at elevations of 100 to 1,300 metres ^{(1) (4)}. In Portugal, the Iberian midwife toad is typically found up to elevations of around 600 metres, although it occurs up to 750 metres in the Serra de Monchique. In Spain, this species is typically more common at lower altitudes, although it occurs at elevations of over 1,000 metres in several areas ⁽²⁾.

Iberian midwife toad habitat

The Iberian midwife toad inhabits dry environments ^{(2) (4)}. It is usually found in meadows and open oak (Quercus) forests, often in areas of sandy soil where small evergreens and other types of vegetation adapted to dry habitats flourish ^{(1) (4)}. 

The Iberian midwife toad is dependent on streams and temporary pools for its tadpoles to develop ^{(1) (2) (4)}.

Iberian midwife toad status

The Iberian midwife toad is classified as Near Threatened (NT) on the IUCN Red List ⁽¹⁾.

Iberian midwife toad threats

The population of the Iberian midwife toad is thought to be decreasing. Although currently a fairly common species across much of its range, populations in Spain in particular have undergone localised declines in recent years, largely due to accelerated destruction of Mediterranean forest habitat ⁽¹⁾. Habitat alteration and the loss of suitable habitat, particularly due to deforestation and logging, are therefore considered the primary threats to the Iberian midwife toad ^{(1) (2) (4)}.

This species’ habitat is also being encroached on by urbanisation and development, while pollution of aquatic habitats and the construction of canals and dams pose additional threats ^{(1) (4)}. The introduction of predatory fishes and the Louisiana crayfish (Procambarus clarkii) may further threaten the reproductive success of the Iberian midwife toad ^{(1) (4)}.

The devastating chytrid fungus, which causes the disease chytridiomycosis, is a potential future threat to the Iberian midwife toad, especially given that it has already affected the closely-related common midwife toad (Alytes obstetricans) in Spain ^{(1) (4)}.

Iberian midwife toad conservation

The Iberian midwife toad is listed on Appendix II of the Bern Convention ^{(1) (9)}, which aims to conserve wild flora and fauna and their natural habitats and to promote European co-operation in conservation ⁽⁹⁾. It is also included on Annex IV of the EU Habitats Directive ⁽¹⁰⁾, and is protected by national legislation in Spain ^{(1) (4)}. 

This species is also known to occur in Cabañeros and Doñana National Parks in Spain ^{(1) (4)}.

Recommended conservations measures for the Iberian midwife toad include closely monitoring its population, especially given the growing threat from the potentially deadly chytridiomycosis ^{(1) (4)}.

Find out more

Find out more about the Iberian midwife toad:

• EDGE - Iberian midwife toad:
  http://www.edgeofexistence.org/amphibians/species_info.php?id=1371
• AmphibiaWeb - Iberian midwife toad:
  http://amphibiaweb.org/cgi-bin/amphib_query?where-scientific_name=Alytes+cisternasii

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Glossary

Amplexus

The mating position of frogs and toads, in which the male clasps the female around the back or waist.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Evergreen

A plant which retains leaves all year round. This is in contrast to deciduous plants, which completely lose their leaves for part of the year.

Fertilisation

The fusion of gametes (male and female reproductive cells) to produce an embryo, which grows into a new individual.

Gland

An organ that makes and secretes substances used by the body.

Nocturnal

Active at night.

Territorial

Describes an animal, a pair of animals or a colony that occupies and defends an area.

Tympanum

Also known as the eardrum. A thin membrane that transmits sounds from the air to the middle ear.

References

1. IUCN Red List (September, 2011)
   http://www.iucnredlist.org/
2. AmphibiaWeb - Iberian midwife toad (September, 2011)
   http://amphibiaweb.org/cgi-bin/amphib_query?where-scientific_name=Alytes+cisternasii
3. Halliday, T. and Adler, K. (2002) The New Encyclopedia of Reptiles and Amphibians. Oxford University Press, Oxford.
4. EDGE - Iberian midwife toad (September, 2011)
   http://www.edgeofexistence.org/amphibians/species_info.php?id=1371
5. Márques, R. and Bosch, J. (1997) Female preference in complex acoustical environments in the midwife toads Alytes obstetricans and Alytes cisternasii. Behavioral Ecology, 8(6): 588-594.
6. Zug, G.R., Vitt, L.J. and Caldwell, J.P. (2001) Herpetology: An Introductory Biology of Amphibians and Reptiles. Academic Press, Elsevier, Maryland Heights, Montana.
7. Wells, K.D. (2007) The Ecology and Behaviour of Amphibians. University of Chicago Press, Chicago.
8. Márques, R. (1995) Female choice in the midwife toads (Alytes obstetricans and A. cisternasii). Behaviour, 132(1-2): 151-161.
9. Council of Europe: Bern Convention (September, 2011)
   http://conventions.coe.int/Treaty/EN/Treaties/Html/104.htm
10. EC Habitats Directive (September, 2011)
    http://www.jncc.gov.uk/page-1374