A new species of rain frog (Anura: Strabomantidae: Pristimantis) from the Guiana Shield and amended diagnosis of P. ockendeni (Boulenger, 1912)

Pristimantis is already the most speciose genus among vertebrates, yet the current number of species remains largely underestimated. A member of the P. unistrigatus species group from the Guiana Shield has been historically misidentified as P. ockendeni, a species described from southern Peru. We combined mitochondrial (16S and COI) and nuclear (RAG1) loci, external morphology, skull osteology (μ-CT scan), vocalization (advertisement and courtship calls), geographic distribution and natural history data to differentiate the Guiana Shield populations from P. ockendeni, and describe them as a new species. The new species is crepuscular and nocturnal and inhabits the understory of unflooded (terra firme) forests in Brazil, Guyana and Suriname. It is phylogenetically related to P. arda­lonychus, P. martiae and undescribed species from Brazilian Amazonia. The new species notably differs from P. ockendeni and its congeners in the P. unistrigatus species group occurring in the Guiana Shield by the combination of the following characters: absence of dentigerous processes of vomers, presence of vocal slits in males, body size (SVL 16.2–20.7 mm in males and 21.4–25.7 mm in females), advertisement call (call with 4–6 notes, call duration of 158–371 ms and dominant frequency of 3,466–4,521 Hz) and translucent groin coloration in life. To facilitate the recognition and description of cryptic species previously hidden under the name P. ockendeni, we provide an amended diagnosis of this taxon based on external morphology and advertisement call of specimens recently collected nearby the type locality and additional localities in southwestern Amazonia.