This species occurs in Argentina in north-west Corrientes Province (A. s. pederseni) and Entre Rios and Buenos Aires Provinces (A. s. siemersi). In Uruguay, it occurs in two localities in San Jose and Rocha states (A. s. siemersi). It occurs at elevations of 0-70m asl.
Habitat and Ecology
A. s. pederseni occurs in leaf axils of terrestrial Aechmae bromeliads in gallery forests along main river systems. It reproduces in temporary pools close to the bromeliads. The nominal subspecies occurs and reproduces in wetlands and river deltas (Río Paraná), and tolerates moderate habitat disturbance.
The nominal subspecies was known to be uncommon, and the last record is from 1982. All populations have disappeared from Argentina and Uruguay, the reason for which is not well understood. However, in 1983, the Paraná had the largest flood of the century and the population here subsequently disappeared and has not been found since, despite many attempts to relocate it. The subspecies A. s. pederseni is rare but was recorded in 2002 and 2003, and this population at least appears to be stable.
The main threat to this species is habitat destruction caused by fires used to expand or maintain pastures and pine forestry plantations. Some populations are also likely to be threatened by the "Hidrovía Paraná-Paraguay" project (the transformation of the Paraguay-Paraná-Uruguay-La Plata river system into a 3,400-km long shipping canal). In Uruguay, this species is threatened by draining of wetlands for agricultural expansion.
Some populations of A. s. pederseni occur in the 17,600-ha Parque Nacional Mburucuya. The existing protected areas network requires expansion to ensure the protection of lowland riverine and wetland habitats. Further survey work is necessary to determine the status of populations of the nominate subspecies.
Red List Status
Listed as Endangered because its Area of Occupancy is probably less than 500km2, its distribution is severely fragmented, and the extent of its gallery forest habitat in Corrientes Province is probably declining.
There are two subspecies: Argenteohyla siemersi siemersi and A. s. pederseni.
Esteban Lavilla, Jorge Céspedez, Diego Baldo, Boris Blotto, Jose Langone 2004. Argenteohyla siemersi. The IUCN Red List of Threatened Species 2004: e.T55302A11285912. http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T55302A11285912.en