Fig. 1 in Feeding habits of the threatened aquatic Andean frog Telmatobius rubigo (Anura: Telmatobiidae)

Fig. 1. Adult male of Telmatobius rubigo in its natural habitat in the locality of Santa Catalina, Jujuy province, Argentina. Photo by Mauricio Sebastián Akmentins. de Los Pozuelos basin (Barrionuevo and Abdala 2018; The frogs were located in the rivers through an active Barrionuevo and Baldo 2009). This fully aquatic frog search by visual encounter (Crump and Scott 1994), has a unique feeding behavior among anurans, using a during January and March 2020 (Fig. 1). The frogs specialized feeding mechanism of inertial suction to were captured manually, and the stomach contents were capture their prey (Barrionuevo 2016). Beyond this obtained in situ by the modified technique of stomach singular prey capture mechanism, the knowledge about flushing (Legler and Sullivan 1979; Solé et al. 2005), the trophic ecology of this species remains incomplete. which avoids mortality of the frogs. The stomach This study analyzed the feeding habits of the Laguna contents were individually preserved with 70% ethanol de Los Pozuelos' Rusted Frog in the desert Puna in 1.5 ml polypropylene tubes for subsequent analysis. environment of Jujuy province, Argentina. Due to the For each frog, the sex was recorded based on secondary combination of a strictly aquatic life habit and the inertial sexual characters, such as nuptial pads and keratinized suction feeding mechanism, we expected a predominance spicules on the chest (Barrionuevo and Baldo 2009). The of aquatic items in the diet of this species. Determining size of each frog was measured as the Snout-Vent Length the composition of prey can provide valuable biological (SVL) with a digital dial caliper to the nearest 0.1 mm information to better understand the ecology of this (Mitutoyo Absolute Digimatic, Kawasaki, Japan) and threatened aquatic Andean frog. each frog was weighed with a portable digital scale to the nearest 0.1 g (OHAUS, Parsippany, New Jersey, USA). Materials and Methods After diet samples and measurements were taken, the frogs were released at the capture site. The study was conducted in three localities of occurrence The stomach contents were analyzed under a of Telmatobius rubigo in Jujuy province, Argentina stereomicroscope, and prey were identified to the level (Barrionuevo and Abdala 2018): Queta, in the southern of subclass for Annelida, and to the level of order or distributional range (22°43'7.88"S, 65°58'19.71"W; family for Arthropoda. For each item (prey category), 3,548 m asl); Casa Colorada, in the western distributional the number (N), volume (V), and occurrences (F) were range (22°22'8.9"S, 66°13'29.7"W; 4,333 m asl); and calculated as both absolute and percentage values. The Santa Catalina, in the northern distributional range, volume for intact prey items was estimated according near the type locality of the species (21°56'58.2"S, to the formula used by Dunham (1983) for a prolate 66°02'21.6"W; 3,802 m asl). These localities are in the spheroid: V= 4/3 π x (prey length/2) x (prey width/2)2. Central Andean Puna ecoregion (Dinerstein et al. 1995). The representativeness of the diet sample was The climate is typical of high-altitude desert, being cold evaluated by constructing a coverage-based (species and dry with large daily thermal fluctuations. Precipitation richness) rarefaction curve for incidence data (Chao and events are scarce, occurring as snow and hail in the winter Jost 2012), using iNEXT package, version 2.0.5 (Chao et and rain in summer (Barrionuevo and Baldo 2008). al. 2016) in the program R (R Core Team 2017).