**1. Introduction**

The terrestrial-breeding frog genus *Noblella* Barbour, 1930 [1] (Strabomantidae) is distributed in the Andes–Amazon region of Ecuador, Peru, Brazil, and Bolivia and currently includes 14 species: *N. carrascoicola* (De la Riva and Köhler, 1998) [2], *N. coloma* Guayasamin and Terán-Valdez, 2009 [3], *N. duellmani* (Lehr, Aguilar, and Lundberg, 2004) [4], *N. heyeri* (Lynch, 1986) [5], *N. lochites* (Lynch, 1976) [6], *N. lynchi* (Duellman, 1991) [7], *N. madreselva* Catenazzi, Uscapi, and von May, 2015 [8], *N. myrmecoides* (Lynch, 1976) [6], *N. naturetrekii* Reyes-Puig et al. [9], *N. personina* Harvey, Almendáriz, Brito-M., and Batallas-R., 2013 [10], *N. peruviana* (Noble, 1921) [11], *N. pygmaea* Lehr and Catenazzi, 2009 [12], *N. ritarasquinae* (Köhler, 2000) [13], and *N. thiuni* Catenazzi and Ttito, 2019 [14]. Most of these species inhabit montane forests above 1000 m and are morphologically very similar to those in the genus *Psychrophrynella* Hedges, Duellman, and Heinicke 2008 [15]. Recent analyses indicate that there is uncertainty regarding the relationships among species of *Noblella* and *Psychrophrynella* [14,16]. Hedges et al. [15] assigned *N. peruviana* and *P. bagrecito*, respectively, as type species of the two genera. However, the lack of DNA sequences for both *N. peruviana* and *P. bagrecito* has prevented researchers from resolving the phylogenetic relationships between *Noblella* and *Psychrophrynella*. Additionally, recent studies have inferred the non-monophyly of the genus *Noblella* [14] and researchers identified a "northern clade" and a "southern clade" containing species ascribed to *Noblella* [9,14]. This taxonomic issue will only be properly resolved when sequences from *N. peruviana* become available. In the meantime, the description of new species will continue advancing our knowledge of the diversity of these small terrestrial-breeding frogs. Here, we describe and name a new species of *Noblella* on the

basis of specimens collected in the lowland Amazon forest and the montane forest of the Amazonian Andes in southern Peru.

## **2. Materials and Methods**

## *2.1. Fieldwork and Data Collection*

We conducted fieldwork at Los Amigos Biological Station (12◦34-07-- S, 70◦05-57-- W, 250 m a.s.l.), located in the Madre de Dios region, Peru, and at various sites along the Kosñipata Valley, located in the Cusco region, Peru [17]. Specimens were euthanized by immersion in benzocaine hydrochloride solution (250 mg/L), where animals were kept for 10 to 20 min, until movement ceased, or by application of 20% benzocaine paste to the ventral region. After euthanasia, tissue samples (e.g., liver, muscle) were taken from the animals and preserved in 2 mL cryogenic tubes filled with RNAlater or 95% ethanol. Following tissue collection, specimens were fixed in 10% formalin, and permanently stored in 70% ethanol, except for specimens collected in 2018, which were fixed in 95% ethanol and stored in 70% ethanol. Sex and maturity of specimens were determined by observing sexual characters and gonads through dissections. Photographs were taken by R. von May, R. Santa Cruz, C. Whitcher, and A. Catenazzi, and were used for descriptions of coloration in life. We were unable to record calls of the new species.

Use of vertebrate animals was approved by the Animal Care and Use committees of the University of California (ACUC #R278-0412, R278-0413, and R278-0314), the University of Michigan (PRO00008306), Florida International University (IACUC #18-009), and Southern Illinois University (IACUC protocol #16-006).
