Vocalizations of the Talamancan Robber Frog, Craugastor talamancae (Anura: Craugastoridae)

is a species of frog that lives in undisturbed lowland forests on the Atlantic versant of Costa Rica, Nicaragua, and Panama at elevations from 0-650 m (Savage 2002;Crawford and Smith 2005;Sunyer et al. 2009; Fig. 1).The species was first described from the type locality of Almirante, Panama (Dunn 1931).Craugastor talamancae is a medium-sized (SVL = 30-50 mm), brownish frog with a dark bar running through the eye and often with a pale upper lip, especially in juveniles.Males of this species have vocal slits, a subgular vocal sac, and nuptial pads (Savage 2002;Hedges et. al 2008).During the day, C. talamancae spends much of its time in the leaf litter, becoming active at night and moving to low vegetation after dark (Savage 2002).This species currently belongs to the Craugastor fitzingeri species group (Padial et al. 2014), which consists of six frogs, including the closely-related C. crassidigitus (Taylor 1952) and C. fitzingeri (Schmidt 1857).The advertisement calls of the frogs in this species group are said to consist of "a series of chirps, mews, or clacks" (Hedges et al. 2008).The advertisement call of C. talamancae has been described variously as a high-pitched "mew" (Savage 2002) or a "squawk" (Cossel and Kubicki 2017).However, no quantitative, formal descriptions of any vocalizations have been made for this species.Our objective was to describe the temporal and spectral characteristics of the vocalizations of this species and compare them to those of the closely-related taxa C. crassidigitus and C. fitzingeri.We made in-situ recordings of Craugastor talamancae around 2200 h on 19-20 May 2017, at La Selva Biological Research Station, located in Heredia Province, on the Caribbean versant of Costa Rica (10.25509N, 84.00298 W; WGS 84; elev.75 m asl).Additional recordings were made at La Selva around 2200 h on 23-24 May 2019.Weather conditions were measured on both occasions with a digital Kestrel™ 3000 weather meter.We located frogs by walking along existing trails and listening for vocalizations of the focal frog.We used white light to find the frogs and then switched to ambient or red LED light so the frog would not be disturbed while calling.We made ~92 minutes of audio recordings during frog vocalizations using a Tascam DR-100 audio recorder and Sennheiser MKE-600 shotgun microphone, with the microphone at a distance of 0.5-3 m from each focal frog.Sample recordings are archived with Fonozoo (accession # 14195-14197).We captured frogs temporarily to obtain morphometric measurements and photographic vouchers.Snout-vent lengths (to the nearest 0.1 mm) were recorded using calipers, and mass (to the nearest 0.1 g) was determined using a Pesola spring scale.We analyzed and graphically constructed spectrograms and waveforms using Raven Pro 64 v1.6 (Center for Conservation Bioacoustics 2014).We found that ambient noise was loud enough in our recordings to obscure details in Vocalizations of the Talamancan Robber Frog, Craugastor talamancae (Anura: Craugastoridae)