Strong differentiation between amphibian communities on two adjacent mountains in the Upper Rio Pastaza watershed of Ecuador, with descriptions of two new species of terrestrial frogs

Abstract

We present the results of herpetological surveys in two adjacent mountains where the EcoMinga Foundation protects the cloud forest in the Upper Rio Pastaza watershed, in the Llanganates Sangay Ecological Corridor in Ecuador. A rapid assessment of the amphibian communities of the study sites reveals a diverse and heterogeneous composition, dominated by terrestrial frogs from the genus Pristimantis. We also identify a cryptic diversity with a significant number of candidate new species. We describe two new species of terrestrial frogs of the genus Pristimantis. Pristimantis maryanneae sp. nov. is characterised by not having tympanum externally visible and having 2–3 subconical tubercles in the upper eyelid; and Pristimantis burtoniorum sp. nov. is characterised by the presence of red colouration in hidden surfaces of the hind-limbs, tubercles on the upper eyelid, interorbital tubercle and a row of rounded tubercles along the snout to the tip and a pale red venter with dark brown mottled pattern. Our samples from the two Reserves do not share species between them, so the proportion of shared species seems to be relatively low. In addition, we highlight the importance of updating the knowledge of amphibians that are restricted to this important conservation region and comment about the threats and composition of the amphibian communities on the eastern slopes of the Upper Rio Pastaza watershed.