Abstract
Poison dart frogs are one of the most studied and charismatic groups of amphibians, yet diversity within small and geographically restricted genera such as Excidobates remains incompletely understood. Until recently, this genus was known to comprise only three species distributed across the eastern mountain ranges of southern Ecuador and northern Peru. Here, we describe a new species represented by two populations in southern Ecuador: one from the eastern slopes of the Andes and another from north of Cordillera del Cóndor. The new species is more closely related to Excidobates mysteriosus, from which it differs by a genetic distance of 2.7–3.5% (16S rRNA gene) and markedly distinctive morphology such as 15.1–18.3 mm on snout-vent length and strongly granular skin. The two populations of the new species differ markedly in color from each other and from E. mysteriosus: scarlet red mottled dorsal coloration on a black background and a red-orange and black reticulated venter in the Central Andean Cordillera population, and green dorsal coloration with inconspicuous yellow spots and a yellow and black reticulated venter in the Cordillera del Cóndor population. Its advertisement call has 24–26 pulses, dominant frequency 4781.3–5062.5 Hz, and 0.51–0.56 s duration. The two populations are separated by 65 km, inhabit different forest types and have a genetic distance of 0.6–0.7%. Despite the marked color and habitat differences, the combined evidence indicates that the two populations represent polymorphic variants of the same species. Because the new species faces severe and imminent threats, including large and medium-scale mining, hydroelectric development, and illegal wildlife trade, we propose to assign it to the Red List category as Critically Endangered. Our findings highlight the rich but still underestimated amphibian diversity of the southeastern Ecuadorian Andes and underscore the urgent need for conservation actions in these regions.
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