Eastern spadefoot toad (Pelobates syriacus)

Pelobates-syriacus-foto

The Pelobates genus is an ancient group of digger toads which includes four species: Pelobates varaldii (found in western Africa), Pelobates cultripes (found in western Europe), Pelobates fuscus (with a central-eastern distribution) and Pelobates syriacus (with an eastern distribution). From these, only Pelobates fuscus and Pelobates syriacus live in Romania [4; 5; 6].

The Geographic Range of Pelobates syriacus in Europe [7]

The Geographic Range of Pelobates syriacus in Europe [7]

The eastern spedefoot toad has an irregular distribution along the alluvial plain of the Danube on the territory of Romania. It can be found at altitudes varying from 0 to 20 meters [2; 5; 6] and the presence or absence of the species in certain areas of the country is related to the type of the habitat.

The Geographic Range of Pelobates syriacus in Romania [2]

The Geographic Range of Pelobates syriacus in Romania [2]

Morphology. It is a large size toad, resembling at first sight with species of the Bufo genus (Bufo viridis). The head is wide with a flat forehead between the eyes and irregularities in the nasal and frontal-parietal areas. The snout of the juveniles is slightly edged and it becomes rounder as they turn into adults. The eyes are large and protruding with vertical pupils [5; 6]. The front feet are relatively robust, with long toes and at the shoulders of adult males they are provided with two protuberances resembling shoulder straps which are in fact glands by means of which we can distinguish males from females. The hind legs are relatively short and robust with rather short toes and an interdigital membrane which is not very well developed. As in the case of Pelobates fuscus, we can observe a very well developed bony metatarsal tubercle in the shape of a spade with which the toad buries itself in the ground. The tibial tarsal joint of the hind leg reaches the eye when we extend the leg along the body [5; 6]. The skin is rather smooth and covered with few small warts. Males lack vocal sacs and nuptial pads [5; 6].

Color. The back of this species is greyish white with olive-green irregular large spots. The ventral part has an uniform pearled-white color on which we can sometimes observe small darker grains [5; 6]. Very rarely there can be 1-3 medium size darker spots. Males can have some small redish warts on the sides, on the femur or on the lateral dorsal part [5; 6].

Ecology. The eastern spadefoot toad lives mainly on land and it can be rarely found in the water outside the breeding season. It is a nocturnal species and during the day it stays buried into the ground at a depth of 30-50 cm. After nightfall it emerges from its shelter in order to feed on different invertebrates such as: snails, insects, earthworms. The young can be active during day time when the weather is rainy. It can be found in sandy lowlands avoiding rocky areas [5; 6]. If it feels threatened it doesn’t try to run from the danger but it hides in the ground thus being difficult to be observed due to its specific color. In case it is further threatened it bloats becoming quite hard.

Reproduction. The migration of the adults to the breeding ponds takes place from March till April depending on annual temperatures. This species usually has an explosive reproduction which lasts for few days. Massive concentrations of individuals and pairs in amplexus can be observed in this period. You can sporadically see pairs in amplexus throughout the entire breeding season. They usually reproduce in temporary pools with shallow water. Eggs are laid under the form of relatively long strings. The strings which are identical with the ones of Pelobates fuscus are thick with 4-5 rows of eggs and they are tangled in the vegetation. The tadpoles can reach very large sizes up to 15 cm. They are almost imposible to be differed from the Pelobates fuscus tadpoles. The differences are morphological and focus on characteristics which can be hardly observed with a naked eye. They can exist as tadpoles for 2-3 months but under certain conditions the tadpoles can hibernate until the next spring [5; 6].

Legislation. In Romania, this species is protected by Law 13 of  1993 through which Romania ratified the Berne Convention (Annex II, III), Law no. 462/2001 on protected natural areas, natural habitats, wild flora and fauna (Annex III, IV), Government Emergency Ordinance no. 57/2007 on the statute of protected natural habitats, flora and fauna, as amended and supplemented, considered species of Community interest that require a strict protection (Annex III, IV A) [9; 10; 11; 12].

According to the IUCN classification, at a global level, this species has a Least Concern status (LC), and in the Red Book of Vertebrates of Romania it is marked as Endangered (En) [8; 13].

References

1. Cogălniceanu D., Aioanei F., Bogdan M., (2000): Amfibienii din România, Determinator. Editura Ars Docendi, Bucureşti. [in Ro]

2. Cogălniceanu D., Szekely P., Samoilă C., Iosif R., Tudor M., Plăiaşu R., Stănescu F., Rozylowicz L., (2013): Diversity and distribution of amphibians in Romania, Zookeys 296:25-57.

3. Covaciu-Marcov S.D., Ghira I., Cicort-Lucaciu Al. Şt., Strugariu Al., Bogdan H.V., (2006): Contributions to knowledge regarding the geographical distribution of the herpetofauna of Dobrudja, Romania, North-Western Jurnal of Zoology, Vol. 2, No. 2: 88-125.

4. Ford L.S., Cannatella D.C., (1993): The major clades of frogs. Herpetological Monographs 7: 94-117.

5. Fuhn I.E., (1960): Amphibia. In: Fauna R.P.R., Vol. XIV, Fasc. 1, Ed. Academiei R.P.R., Bucureşti. [in Ro]

6. Fuhn I.E., (1969): Broaște, șerpi, șopârle. Ed. Ştiinţifică, Bucureşti. [in Ro]

7. Gasc J.P., Cabela A., Crnobrnja-Isailovic, Domen D., Groessenbacher K., Haffner P., Lescure J., Martens H., Marinez Rica J.P., Maurin H., Oliveira M.E., Sofianidou T.S., Veith M., Zuiderwijk A., (1997): Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica & Museum National d’Histoire Naturelle Paris.

8. Iftime A., (2005): Reptilia. In: Botnariuc & Tatole (eds): Cartea Roşie a Vertebratelor din România, Ed. Acad. Române, București. [in Ro]

9. ***Legea 13 din 1993 prin care România ratifică Convenţia de la Berna. [in Ro]

10. *** Directiva Europeană 92/43/EEC. [in Ro]

11. ***Legea nr. 462/2001 privind regimul ariilor naturale protejate, conservarea habitatelor naturale, a florei şi faunei sălbatice. [in Ro]

12. ***Ordonanţa de Urgenţă a Guvernului nr. 57/2007 privind regimul ariilor naturale protejate, conservarea habitatelor naturale, a florei şi faunei sălbatice, aprobată cu modificări şi completări ulterioare. [in Ro]

13. *** www.iucnredlist.org

14. *** www.pelobates.ro

Text and Photo – Buhaciuc Elena