AN INTERESTING FINDING IN MUSEUM COLLECTIONS

AN INTERESTING FINDING IN MUSEUM COLLECTIONS

During the processing the collections of amphibians and preparation of the next catalog of Zoological Museum of the Lviv University curator funds of I category Andrij Zatushevskyy and Iryna Bilyak detected Jambato Toad Atelopus ignescens (Cornalia, 1849), frogs species which is considered extinct.

Sample collection belonging to an unknown author, originating in the late XIX–early XX century. In most collections are about 20 species of amphibians from the region of Central America, but unfortunately all of them without labels.

Description

Atelopus ignescens has uniformly black coloration on its back and flanks, with small round warts covering most of the back. The venter is wrinkled and is bright orange to red in life, becoming darker in the gular region and lighter on the belly. The ventral surfaces of the limbs are black, except for the forelimbs, which are orange-red underneath. The iris is black. In preservative the bright underside turns to a cream color with some poorly defined black markings (Coloma et al. 2000).

Distribution and Habitat

The species has only been found in the humid forests of Imbabura, Pichincha, Cotopaxi, Napo, Chimborazo, and Bolívar provinces in the northern Andes of Ecuador between elevations of 2800-4200 meters. Habitat includes inter-Andean valleys and sub-paramo and paramo habitats between the western and eastern cordilleras of the Andes (Coloma et al. 2000). Atelopus ignescens was previously abundant and widely distributed across its range. Studies in the 1960s, 1970s, and early 1980s found large numbers of specimens, while anecdotal evidence from as far back as 1864 also suggests great abundance. Survey evidence suggests that the species was still abundant in some localities between 1984 and 1986, but populations apparently rapidly dropped off around that time. Despite extensive searching, none have been found in the wild since 1988, so the species is now believed to be extinct (Ron et al. 2003).

Life History, Abundance, Activity, and Special Behaviors

Atelopus ignescens was diurnal, terrestrial, and moved slowly, making it easy to locate when present (Ron et al. 2003).

Trends and Threats

It is not known what caused the extinction of A. ignescens. The most likely cause is an outbreak of the fungal disease chytridiomycosis, which has been responsible for amphibian population declines in various parts of the world (Ron et al. 2003), and particularly among high-elevation populations of Atelopus species (La Marca et al. 2005). The first case of chytridiomycosis in Ecuador was discovered in 1980, just a few years before A. ignescens began to decline.

Habitat degradation may have contributed, as 27.1% of the paramo and 33.3% of Andean forests have been cleared in Ecuador (Ron et al. 2003). However, this species is able to withstand some degree of habitat degradation. In addition, there is little evidence of human interference in two protected areas where the species was previously found but now is not. Thus habitat degradation is probably not the main cause of this extinction (Ron et al. 2003).

Another possible cause is the presence of introduced predatory fishes, as two exotic species of salmonids have been found in streams and lakes of Ecuador’s highlands. However, this idea is not corroborated by evidence of predation. In addition, salmonids have been found within the range of A. ignescens since the 1950s, long before the toads’ decline. Furthermore, the salmonids are not found throughout the entire range of A. ignescens (Ron et al. 2003).

Another possible factor may be the dramatic increase in mean annual temperature in Ecuador in recent years. Of ninety years of climatic data analyzed in a study by Ron et al., the year 1987 saw the most extreme combination of warm and dry conditions. These conditions may have increased adult toad mortality, reduced reproductive success, or made the toad more vulnerable to attack by weakening immune function (Ron et al. 2003).

Possible reasons for amphibian decline

General habitat alteration and loss

Habitat modification from deforestation, or logging related activities

Habitat fragmentation

Predators (natural or introduced)

Disease

Climate change, increased UVB or increased sensitivity to it, etc.

Article by Benjamin Fryer (bfryer AT berkeley.edu), University of California at Berkeley http://amphibiaweb.org/species/55