Noblella thiunisp. n., a new (singleton) species of minute terrestrial-breeding frog (Amphibia, Anura, Strabomantidae) from the montane forest of the Amazonian Andes of Puno, Peru

Abstract

We describe a new species of minute, terrestrial-breeding frog in the genusNoblella. We collected a single specimen in the leaf litter of primary montane forest (2,225 m a.s.l.) near Thiuni, in the Provice of Carabaya, Department of Puno, in the upper watershed of a tributary of the Inambari River of southern Peru, the same locality where we found the types ofPsychrophrynella glaucaCatenazzi & Ttito 2018. We placed the new species withinNoblellaon the basis of molecular data, minute size, and overall morphological resemblance with the type speciesN. peruvianaand other species ofNoblella, including having three phalanges on finger IV (as inN. coloma,N. heyeri,N. lynchi,N. madreselva,N. peruviana, andN. pygmaea), and terminal phalanges T-shaped and pointed.Noblella thiunisp. n. is distinguished from all other species ofNoblellaby having ventral surfaces of legs bright red, and chest and belly copper reddish with a profusion of silvery spots. The new species further differs from known Peruvian species ofNoblellaby the combination of the following characters: tympanic membrane absent, eyelids lacking tubercles, dorsal skin finely shagreen, tarsal tubercles or folds absent, three phalanges on Finger IV, tips of digits not expanded, no circumferential grooves on digits, inguinal spots present. The new species has a snout–vent length of 11.0 mm in one adult or subadult male. Our new finding confirms the high levels of endemism and beta diversity of small, terrestrial-breeding frogs inhabiting the moss layers and leaf litter in the montane forests of the Amazonian slopes of the Andes and adjacent moist puna grasslands, and suggests much work remains to be done to properly document this diversity.