37.
Moroccan Spadefoot Toad
(Pelobates varaldii)
EN
Overview
The Moroccan spadefoot toad is a burrowing species, spending half the year in a dormant state underground. It is only active in the autumn and winter when it comes to the surface during the night to feet. They do not really hunt for their prey, but rather wait for invertebrates to come to them. This species tends to breed in temporary pools which form after heavy rains. Eggs hatch after a week of being laid and the tadpoles metamorphose in May/June. This species is threatened by habitat destruction and does not occur in man-altered areas. It is especially affected by arable cultivation and livestock farming within its range.
Urgent Conservation Actions
Further surveys to determine the exact range - it is important to determine whether this species occurs in the Merja Serga Biological Reserve; habitat protection.
Distribution
Northwestern Morocco
Fact
The Moroccan spadefoot toad is the only representative of the genus Pelobates that is found in Africa. The other three species all have European/Middle Eastern distributions.

A close relative of the Moroccan spadefoot toad, Pelobates fuscus, is sometimes commonly known as the “garlic frog” because of the odour it gives off when threatened.
Associated Blog Posts
24th Feb 09
We have just received this blog from EDGE Community member Philip de Pous, with an updated on his current work in Morocco: After ten weeks of research in ...  Read

Evolutionary Distinctiveness
Order: Anura
Family: Pelobatidae
The family Pelobatidae (commonly known as the “spadefoot toads”) is small, comprising only 4 species with a wide distribution from Europe to Central Asia and Morocco. The spadefoot toad family previously encompassed another seven other species from North America (U.S.A. and Mexico), but these genera (Scaphiopus and Spea) were moved to their own family Scaphiopodidae (commonly known as the “burrowing frogs”). Although these two families are still thought to be closely related, they have been separated by the Atlantic Ocean for up to 150 million years and, despite looking very similar, they are believed to have diverged sufficiently to warrant separate families.

Spadefoot toads are usually confined to dry areas with sandy soils. A common physical trait that unites the spadefoot toads is the presence of a sharp-edged projection (or “tubercle”) on each hind foot which is used for the purpose of burrowing. All members of this family are strictly nocturnal (or night active), and during the day tend to hide in deep burrows where they are capable of tolerating high levels of water loss. They all have a short-legged, squat appearance and have developed strategies to survive the longest droughts, only emerging from their borrows during humid nights to feed. Some species of spadefoot toad have been found to produce two types of tadpole – a plankton feeding variety that survives if rains are plentiful, and a cannibalistic type that feeds on the stranded plankton feeders in dryer years.

The spade foot toads are an ancient amphibian lineage, diverging from their closest relatives around 120 million years ago in the early Cretaceous periods. This is 55 million years before the extinction of the dinosaurs and 30 million years before the first bird appeared in the fossil record. They began evolving as a distinct family 25 million years before the common ancestor of the kangaroo and tiger! The spadefoot toads 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.

Despite considerable geographical distance, the Moroccan spadefoot toad’s closest relative, the Western spadefoot toad (Pelobates cultripes), looks very similar. In fact, Old World spadefoot toads (of Europe, Central Asia and Africa) also resemble their close relatives in the genus Scaphiopus (the New World family of burrowing toads in North America), despite being separated for between 75-150 million years. Whilst the Western and Moroccan spadefoot toads have changed genetically, these changes have had very little effect on the overall appearance of these amphibians. In the absence of major environmental change, the ancestral appearance (or morphology) reflects a set of physical characteristics which ensure the survival and reproduction of both species. The Sahara desert existed throughout the Tertiary period (between 65 and 1.6 million years ago), with moderate fluctuations in size and aridity. Moist woodland has been marginal and has fluctuated in its degree of presence, but southern Spain (the area of the Western spadefoot toad) and Mediterranean Morocco (where the Moroccan spadefoot toad is found) have been influenced by similar environmental and human-population effects through the intervening time since their speciation (the point at which they became separate species). The strait of Gibraltar is estimated to have formed between 5.5 and 7 million years ago, geographically separating Europe and Africa, and two major populations of the ancestors of the Western and Moroccan spadefoot toads. Genetic studies have indicated that the Moroccan spadefoot toad diverged from the Western spadefoot toad, 8-11 million years ago. Adding the information suggested by geological data of 5.5-7 million years ago for the opening up of the Strait of Gibraltar, these two species probably last had contact at least 5 million years ago, which is well over 4 million years before the origin of modern humans. The Moroccan spadefoot toad is the only member of its family that survives in Africa.
Description
This is a toad-like species with fairly smooth skin but no prominent glands either side on its head behind the eyes (also called paratoid glands), which are often found in toads. Males measure about 65 mm in total length, whilst females are slightly larger at 70 mm. The head is wide with a slightly pointed nose. The eyes are very large and prominent, and yellowish copper or greenish with tiny black spots. Small reddish warts are present on the eyelids and along the back. The colouration is greyish brown with irregular dark spots. The ventral (or lower) surfaces are whitish brown.
Ecology
The Moroccan spadefoot toad is generally “fossorial” (or burrowing) in its lifestyle. It digs into lowland sandy, uncultivated soils with specially adapted horny projections (or tubercles) on its hind feet, which is uses to rapidly burrow backwards and straight down into the soil. The spawning sites of this species are most often still, temporary waterbodies (such rain puddles).

This species is nocturnal and is only active in autumn and winter when the nights are sufficiently warm and humid to permit them to make their night-time trips to the surface. They spend their day buried in the soil and appear to be confined to sandy soils. This species makes use of special physiological adaptations for prolonged periods of dormancy. The Moroccan spadefoot toad’s diet comprises diverse invertebrates, but they do not travel far to hunt their prey. They instead tend to emerge from their burrows and wait for their prey to come to them. The home range of a close relative of this species, the Eastern spadefoot toad, was estimated to be no more than 9 m2.

Moroccan spadefoot toads breed after periods of heavy rain at the end of the summer and form explosive breeding aggregations in the temporary pools that form during the down-pours. During mating, the male clasps the female around the waist and fertilized her eggs externally as they are released into the water. Egg-laying takes 5-10 minutes. Up to 1000 are laid in a string that is 1-1.5 m long and are grey in colour, each measuring just 1.15-2 mm in diameter. The tadpoles hatch at the latest within a week after laying, which is an important adaptation given the transitory nature of these pools. They feed on plankton and detritus and reach 130 mm in length before metamorphosis takes place in May and June, and the young leave the water with stubby tails. Recently metamorphosised froglets measure 21-34 mm in total length. The calls of spadefoots toads sould like a loud, harsh clucking, that can sometimes be heard from more than 2 km away when many males call together. Sometimes male spadefoots fight for females, which may be wounded by the struggling hind feet of the males. Group eggs laying may be finished within 2 days, whereupon the toads disappear into their borrows to avoid the heat of the sun.
Habitat
The natural habitats of the Moroccan spadefoot toad are subtropical or tropical dry shrubland, rivers, intermittent rivers, freshwater marshes, and intermittent freshwater marches. This species occupies lowland sandy uncultivated soils, sometimes in the vicinity of cork woodlands. The spawning sites are most often still, temporary waterbodies (such as dayas and rain puddles). The species does not occur in habitats that have been modified by humans.
Distribution
This species is known only from fragmented localised areas on the coastal plains of northwestern Morocco at altitude of lower than 250 metres above sea level. The northernmost location is the town of Larache, while the southernmost population is known from the northeastern part of the salt marshes of Oualidia. The Moroccan spadefoot toad may range further south than Oualidia, but this possible range extension requires further investigation. In 1986 the herpetologists Yus Ramos and Cabo Hernandez posited that the presence of the Western spadefoot toad in the Melilla region of Spain might refer to a hitherto unknown population of the Moroccan spadefoot toad, although this record is far outside the known range of any spadefoot toad species.
Population Estimate
This species is known to be declining, although further details of abundance are required before an accurate population estimate can be given.
Population Trend
The Moroccan spadefoot toad is thought to be in decline by the ICUN Red List of Threatened Species.
Status
The Moroccan spadefoot toad is listed as Endangered in the IUCN Red List of Threatened Species because its area of occupancy is probably less than 500 km sq., its distribution is severely fragmented, and there is a continuing decline in the extent and quality of its habitat in Morocco.
Threats
This species is severely threatened by the intensification of livestock pasturing across its range. This is leading to the pollution of stagnant waters with livestock waste, degrading potential spawning sites for the Moroccan spadefoot toad. Additionally, arable agriculture may be leading to the loss or disturbance of the sandy substrate soil habitat, which this species depends upon for its burrows. Populations of this species are now often restricted to temporary ponds, and those remaining associate with permanent waterbodies are being adversely affected by the presence of predatory fishes (e.g. Gambusia holbrooki).
Conservation Underway
It is not known whether the species occurs in any protected areas, although it is possible that it is present in the Merja Serga Biological Reserve. It is not protected by national legislation, and there are currently no conservation measures ongoing for the Moroccan spadefoot toad.
Projects
Conservation Proposed
Further surveys are required to determine the exact range of this species so that planned conservation actions can take all remaining populations into account. It is important to determine whether this species occurs in the Merja Serga Biological Reserve in case reserve management needs to be modified to protect habitat for the Moroccan spadefoot toad. Other habitat areas for this species should also be protected where human land use is having negative consequences for the survival of these toads. This could involve working with local land users to develop more ecologically sensitive land use techniques, that may involve cordoning some areas off from further cultivation or livestock farming. An environmental education programme for local stakeholders could raise the profile of this species and encourage local pride in their biodiversity.
Associated EDGE Community members

Philip is an amphibian ecology and conservation researcher

Wouter is an undergraduate student studying amphibians.

Links
References
AmphibiaWeb: Information on amphibian biology and conservation [web application]. 2006. Berkeley, California: AmphibiaWeb. Available: amphibiaweb. Accessed: 08 December 2006.

Behler, J.L. and Behler, D.A. 2005. Frogs: A Chorus of Colors. Sterling Publishing, NY, U.S.A.

Bons, J. and Geniez, P. 1996. Amphibiens et reptiles du Maroc (Sahara Occidental compris) Atlas Biogéographique. Asociación Herpetológica Española, Barcelona, Spain.

Busack, S.D., Maxson, L.R. and Wilson, M.A. 1985. Pelobates varaldii (Anura: Pelobatidae): a morphologically conservative species. Copeia 1985: 107-112.

Crochet, P.-A. and Geniez, P. 2003. First live record of Pelobates varaldii Pasteur & Bons, 1959 in the Oualidia area (Morocco). Herpetozoa 16(1/2): 93-94.

Dorda Dorda, J. 1984. Prospeccion herpetologica en el Norte de Marruecos. Bol. Ghezoc. 1(1): 19-28.

Duellman, W. E. and Trueb, L. 1986. Biology of Amphibians. McGraw-Hill, New York.

Frost, Darrel R. 2006. Amphibian Species of the World: an Online Reference. Version 4 (17 August 2006). Electronic Database accessible at: . American Museum of Natural History, New York, USA.

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.

Halliday, T. and Adler, C. (eds.). 2002. The new encyclopedia of reptiles and amphibians. Oxford University Press, Oxford.

Herrero, P. and Talavera, R.R. 1988. Cytotaxonomic studies on Iberian and Moroccan Pelobates (Anura: Pelobatidae). Acta Zoologica Cracoviensia 31(17): 505-508.

IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment. Global Amphibian Assessment. Accessed on 08 December 2006.

Mateo, J.A., Plegezuelos, J.M., Fahd, S., Geniez, P. and Martínez-Medina, F.J. 2003. Los Anfibios, los Reptiles y el Estrecho de Gibralter. Un ensayo sobre la Herpetofauna de Ceuta y su entorno. Instituto de Estudios Ceuties, Ceuta.

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.

Pasteur, G. and Bons, J. 1959. Les Batraciens du Maroc. Trav. Inst. Scient. Chérifien, Rabat, Ser. Zool. 17(14): 1-241.

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.

Salvador, A. 1996. Amphibians of northwest Africa. Smithsonian Herpetological Information Service 109: 1-43.

Salvador, A., Donaire-Barroso, D., Tahar, S. & El Mouden, E.H. 2004. Pelobates varaldii. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. IUCN Red List of Threatened Species.. Downloaded on 06 July 2007.

Schleich, H.H., Kästle, W. and Kabisch, K. 1996. Amphibians and Reptiles of North Africa. Koeltz Scientific Books, Koenigstein.

Yus Ramos, R. and Cabo Hernandez, J.M. 1986. Guia de la naturaleza de la region de Melilla. Excmo, Melilla.

if you can provide new information to update this species account or to correct any errors, please email us at info@edgeofexistence.org


Forum comments

There are as yet no comments for this species.

Add a comment

You must log in to post. If you don't have a login, it's easy to register.