CANTERBURY, England, Oct. 31 (UPI) -- A British-led team of scientists reports the number of frog species has been vastly underestimated, posing concern for biodiversity management.

The researchers from Britain, France and New Zealand collated more than 500 DNA sequences, including 60 previously recognized species, occurring in the Guiana Shield -- the largest continuous tract of virgin tropical rainforest, covering French Guiana, Suriname, Guyana, eastern Venezuela and northern Brazil.

University of Canterbury researcher Antoine Fouquet, the study's lead author, said the samples revealed an astonishing level of cryptic diversity, with the number of species identified potentially two-fold greater than previously thought.

Fouquet said such underestimation of amphibian diversity has particularly broad implications for the many Neotropical amphibians that are considered highly threatened.

Noting frogs are vanishing with unprecedented speed -- it's thought that more than 100 species have become extinct since 1980 -- Fouquet said frogs have become "canaries in the coal mine" and their decline is regarded as an indicator of the environmental crisis.

The study appears in the online journal PLoS One.