Bombina pachypus
Apennine Yellow-bellied Toad
family: Bombinatoridae

© 2009 Andreas & Christel Nöllert (1 of 12)
Conservation Status (definitions)
IUCN (Red List) Status Endangered (EN)
Other International Status Under Bombina variegata: Appendix II of the Berne Convention, Annexes II and IV of the EU Council Directive for the Conservation of Natural Habitats and of Wild Fauna and Flora
National Status None
Regional Status None


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The dorsal surface can range from a dark-tan to a dark-gray color, and the surface of the skin is tubercular. The eye has a triangular pupil. This species is regarded by some workers as a subspecies of Bombina variegata (see that account for a longer description of morphology and coloration).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Italy


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Bombina pachypus is endemic to Italy. It ranges from the southern tip of the Italian mainland, north through the Apennine region (or in Italian, Appenine), where it stops just south of the Po River Valley (DiMartino and Ferri 2002). This species occurs in both terrestrial and freshwater habitats (Andreone and Corti 2006). It is commonly found in unshaded pools in forests and open areas (Andreone and Corti 2006), including pools formed in ditches, irrigation areas, farmland, or pasture land (Guarino et al. 1998).

Life History, Abundance, Activity, and Special Behaviors
Bombina pachypus is diurnal, when it is active. Hibernation takes place from November to late April. This species typically becomes active in May and begins breeding almost immediately, with the period of activity and breeding lasting until September. Although B. pachypus is considered a prolonged breeder due to the long breeding period, a single animal does not reproduce continuously within that period. Multiple distinct periods of calling and oviposition alternate with non-reproductive activity. This reproductive plasticity presumably allows B. pachypus populations to make maximum use of the temporary pools preferred for breeding (Guarino et al 1998). In addition, sperm was found to be constantly present in male testes, but the testes do not always exhibit all stages of spermatogenesis. Males apparently use sperm from the preceding fall for the earlier periods of breeding (Guarino et al. 1998).

The clutch size ranges from a few eggs to a few tens of eggs. It is thought that each female lays a few eggs during each wave of reproduction, but in different temporary pools. However, it is not clear how often females reproduce in the wild. Female frogs in captivity showed varying reproductive activity, with one female laying several eggs multiple times during the month of June, and a few eggs during a short period in September; another female laid a few eggs during a single short period in July; a third captive female did not lay any eggs (Guarino et al. 1998).

This species is relatively long-lived, with an average lifespan of 8 years, and an apparent maximum lifespan of 16 years. Sexual maturity is attained during the third year of life (Guarino et al. 1995).

The species, like others in the genus Bombina, is toxic. The secretions are discharged through the skin when the animal is threatened or stimulated (Barberio et al. 1987). These secretions have also been found to be antimicrobial and antifungal (Barberio et al. 1987, Mastromei et al. 1991). When threatened, the animal will arch its back in response to expose its colorful yellow and black underside as a warning of its toxicity to possible predators (Bajger 1980). This arching of the body is known as the "unken reflex" and the behavior is found throughout the genus Bombina, as well as in some salamanders.

Trends and Threats
This species is thought to be common in suitable habitat (IUCN 2008) but has also been reported as becoming increasingly rare in some parts of its range in southern Italy (Caputo et al. 1992). Bombina pachypus faces a threat from chytrid fungus. This species was the first Italian amphibian to be confirmed with chytrid infection, in the summer of 2001 (Stagni et al. 2004). Neometamorph B. pachypus collected from the hills in the province of Bologna experienced high mortality, dying within one or two weeks from collection and a few days after experiencing symptoms (skin desquamation, locomotor difficulties, dry skin, anorexia, hyperaemia of fingers). In captivity the infection was nearly always fatal for newly metamorphosed B. pachypus froglets, but only sometimes for subadults and adults. In contrast, neometamorphs collected from Tuscan-Romagna areas during the same time period did not show infection or symptoms (Stagni et al. 2004).

It has been postulated that sympatric water frogs of the Rana esculenta complex may act as a reservoir species for chytrid fungus and may contribute to chytrid-related declines in B. pachypus (Simoncelli et al. 2005).

The species may be declining due to the loss of wetland habitat as a result of agricultural damage (Canestrelli et al. 2006). It occurs in several protected areas in Italy, including Parco Nazionale d'Abruzzo, Parco Nazionale Pollino and Parco Nazionale del Gran Sasso e Monti della Laga (IUCN 2008). Parco Nazionale del Gran Sasso e Monti della Laga National Park began a long-term monitoring program for this species in 1999 (Ferri 2000; DiMartino and Ferri 2002).

Between 2005 and 2010, populations of B. pachypus which were associated with man-made aquatic environments(eg. troughs or washtubs) underwent greater decline than those in natural habitats. Maintenance and cleaning by agricultural workers had previously made these ideal for B. pachypus reproductive success, by removing shading and vegetation conducive to tadpole predators such as dragonflies and newts. Inland depopulation and agricultural abandonment since the 1960's, however, has resulted in the overgrowth or complete loss of these cultivated habitats, resulting in decline of B. pachypus (Stefano Canessa, FrogLog 2012).

Relation to Humans
Man-made, regularly maintained water bodies in cultivated environments have become successful breeding sites for this species, as they provide a sustained, unshaded, vegetation free habitat for tadpole development (Stefano Canessa, FrogLog 2012).

Possible reasons for amphibian decline

General habitat alteration and loss
Drainage of habitat
Habitat fragmentation
Loss of genetic diversity from small population phenomena

Bombina pachypus is regarded as a subspecies of Bombina variegata by some workers. It was initially separated from Bombina variegata by Lanza and Vanni (1991) due to genetic distance based on allozymes (Nascetti et al. 1982) and morphological differences (Vaccaneo 1931). Canestrelli et al. (2006) have argued for maintaining it as a separate species, based on analysis of mitochondrial and nuclear markers, and that Calabrian populations deserve special conservation status as the reservoir of significant genetic diversity for this species However, phylogenetic analysis by Hofman et al. (2007), using mitochondrial cyt b sequences, found that Italian populations were nested within B. variegata lineages, calling into question the validity of recognizing B. pachypus as a separate species.


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Barberio, C., Delfino, G., and Mastromei, G. (1987). ''A low molecular weight protein with antimicrobial activity in the cutaneous 'venom' of the yellow-bellied toad (Bombina variegata pachypus).'' Toxicon, 25, 899-909.

Canestrelli, D., Cimmaruta, R., Constantini, V., and Nascetti, G. (2006). ''Genetic diversity and phylogeography of the Apennine yellow-bellied toad Bombina pachypus, with implications for conservation.'' Molecular Ecology, 15(12), 3741-3754.

Di Martino, V., and Ferri, V. (2002). Distribuzione e Iniziative Di Conservazione Di Bombina pachypus Nel Parco Nazionale Del Gran Sasso E Monti Della Laga. Proceedings of Third Conference, Save the Amphibians, Lugano, June 23-24, 2000, Penne (Pescara).

Ferri, V. (2000). Rilevamento di specie di Anfibi minacciate (Speleomantes italicus, Salamandra salamandra gigliolii, Salamandrina terdigitata, Bombina pachypus nel Parco Nazionale del Gran Sasso e Monti della Laga. Indicazioni per la conservazione. Ente Parco Nazionale Gran Sasso e Monti della Laga. Relazione per l'Ente Gestore, Italia.

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Guarino, F. M., Angelini, F., and Cammarota, M. (1995). ''A skeletochronological analysis of three syntopic amphibian species from southern Italy.'' Amphibia-Reptilia, 16, 297-302.

Harrison, R. G. (1993). Hybrid Zones and the Evolutionary Process. Oxford University Press, New York.

Hofman, S., Spolsky, C., Uzzell, T., Cogălniceanu, D., Babik, W., and Szymura, J. M. (2007). ''Phylogeography of the fire-bellied toads Bombina: independent Pleistocene histories inferred from mitochondrial genomes.'' Molecular Ecology, 16, 2301-2316.

IUCN (2008). 2008 IUCN Red List of Threatened Species. Downloaded on 10 October 2008.

IUCN 2008. 2008 IUCN Red List of Threatened Species. Downloaded on 27 November 2008.

Lanza, B., and Corti, C. (1993). ''Erpetofauna italiana: Acquisizioni ed estinzioni nel corso del novecento.'' Supplemento alle Ricerche di Biologia della Selvaggina, 21, 5-49.

Lanza, B., and Vanni, S. (1991). ''Notes on the biogeography of the Mediterranean island amphibians.'' Atti dei Convegni Lincei, 85, 335-344.

Mastromei, G., Barberio, C., Pistolesi, S., and Delfino, G. (1991). ''A bactericidal protein in Bombina variegata pachypus skin venom.'' Toxicon, 29(3), 321-328.

Nascetti, G., Vanni, S., Bullini, L., and Lanza, B. (1982). ''Variabilità e divergenza genetica in popolazioni italiane del genere Bombina (Amphibia, Discoglossidae).'' Bollettino di Zoologia, 49 (Supplement), 134-135.

Simoncelli, F., Fagotti, A., Dall'Olio, R., Vagnetti, D., Pascolini, R., and Di Rosa, I. (2005). ''Evidence of Batrachochytrium dendrobatidis infection in water frogs of the Rana esculenta complex in central Italy.'' Ecohealth, 2(4), 307-312.

Stagni, G., Dall'Olio, R., Fusini, U., Mazzotti, S., Scoccianti, C., and Serra, A. (2004). ''Declining populations of Apennine Yellow Bellied Toad Bombina pachypus in northern Apennines (Italy): is Batrachochytrium dendrobatidis the main cause?'' Italian Journal of Zoology 71 (Supplement 2): 5-13, 71, 5-13.

Vaccaneo, R. (1931). ''Ricerche sui caratteri morfologici dei Bombinator italiani.'' Bollettino dei Musei di Zoologia e di Anatomia Comparata della R. Universitá di Torino, series III, 4, 1-38.

Written by Dustin Guericke, John Cavagnaro (dustingrey AT, Black Hills State University
First submitted 2008-12-19
Edited by Kellie Whittaker (2012-04-03)

Species Account Citation: AmphibiaWeb 2012 Bombina pachypus: Apennine Yellow-bellied Toad <> University of California, Berkeley, CA, USA. Accessed Sep 26, 2017.

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Citation: AmphibiaWeb. 2017. <> University of California, Berkeley, CA, USA. Accessed 26 Sep 2017.

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