The Patagonian Telmatobiid Fauna of the Volcanic Somuncura Plateau of Argentina

Abstract

The Late Tertiary basaltic rocks of the Patagonian Meseta of Somuncura, Rio Negro, Argentina, extend for about 15,000 square km north of 42° South Latitude, approximately 60 miles from the Atlantic coast. It is a flat stepparian landscape of some 1200-1400 m elevation in which many temporary clay-lagoons are scattered. Small rocky streams filter from the basaltic up lands towards the lower slopes of the Meseta, about 700-500 m. The fauna of such an isolated en vironment is very peculiar and a high rate of endemic forms can be emphasized. Two new species of telmatobiid frogs are reported: Telmatobiusreverberii from the clay-lagoons of the stepparian uplands, and Telmatobius somuncurensis from the lower rocky streams. Adults and tadpoles of Telmatobius reverberii are described; this form has morphological and ecological affinities with the smaller Telmatobius praebasalticus of the volcanic lagoons of Neuquen, near the Southern Argen tine Cordilleras. Certain characteristics of Telmatobius somuncurensis are discussed, such as the uncommon everted cloaca and the similarity between the upper and lower rounded structures of its iris and the upper "meniscus" of the iris of the east-Brazilian Cydorhamphus. Probable biogeo graphic relationships and a tentative evolutionary history of these ancient leptodactylid stocks are discussed. * * *

Short Notes

“…Of the eight species in the genus, so far only the larvae of Atelognathus patagonicus (Cei, 1965), Atelognathusreverberii (Cei, 1969) and Atelognathusnitoi (Basso and Úbeda, 1997) have been described. This paper describes the Atelognathus salai larva based on specimens from the type locality, and discusses its similarities to and differences from the other three known larvae in the genus.…”

“…Atelognathus salai larvae have the morphological and morphometric characteristics recognized by Lavilla (1988) as diagnostic for the genus Atelognathus, except for presence of intramarginal papillae in the angular region. The A. salai larva is different from the larvae of the other three known Atelognathus species because its vent tube is not covered by a fold of the ventral n, and it has a double row of marginal papillae on the angular regions (see Cei, 1965Cei, , 1969Echeverría et al, 2001). It is different from A. patagonicus and A. reverberii in having a narrower oral disc and a rounded snout in dorsal view (truncate in patagonicus and reverberii).…”

A new threat for the endangered frog Atelognathus reverberii (Anura: Batrachylidae) in Argentinean Patagonia

“…Dehydration inside these water pits has been observed twice: in November 2013 in the same area and in other "jagüel" located at the type locality of the species, at Estancia El Puntudo (Cei 1969). Cei (1969) mentioned having found dead frogs drowned in jagüeles, but he did not suggest that this might be a threat for the populations of Atelognathus reverberii. Our observations provide a realistic outlook of the possible impact of jagüeles on frog populations.…”

“…Atelognathus reverberii (Cei, 1969) is an endemic terrestrial frog that inhabits volcanic clay lagoons (mostly semi-permanent or temporary). These lagoons are scattered throughout the desertic Somuncura Plateau of Argentinean Patagonia (Cei 1969, Martinazzo et al 2011.…”

“…These lagoons are scattered throughout the desertic Somuncura Plateau of Argentinean Patagonia (Cei 1969, Martinazzo et al 2011. This frog species was listed as Endangered in the IUCN's red list (IUCN 2014) and as Vulnerable in the last categorization of Argentinean amphibian fauna (Vaira et al 2012).…”