Herpetology Notes, volume 14: 231-237 (2021) (published online on 01 February 2021) Diet composition of Atelognathus nitoi (Barrio, 1973) in Chilean Patagonia Nicza Alveal1,2,*, and Helen Díaz-Páez1 Abstract. The availability of data on the diet of a species can be of great importance in understanding its basic biology, as well as contributing to conservation and management. The genus Atelognathus contains five species distributed in the Patagonia region of Chile and Argentina; only A. nitoi occurs in Chile. There are reports on the diet of species of Atelognathus in Argentina, however for A. nitoi studies have focused mainly on taxonomy and systematics. The objective of this study is to provide information on the diet composition of A. nitoi in Chile. A total of 21 specimens of A. nitoi were collected from four localities in Chilean Patagonia during the spring-summer seasons in 2007 and 2010: La Tapera (44°38’S, 71°41’W), Chile Chico (46°32’S, 72°00’W), Cerro Castillo (45°59’S, 71°52’W) and Reserva Nacional Lago Jeinimeni (46°50’S, 71°59’W), XI Región, Chile. We analysed the diet by dissecting the stomach between the cardias and the pylorus. Stomach contents were examined under a stereo microscope and the prey items identified to order or family. Twenty items were determined in 12 taxonomic categories. The highest relative importance index was represented by Dytiscidae, Sylvanidae, Curculionidae and Elateridae, all of the order Coleoptera. The data show that A. nitoi consume a variety of prey, adult and larval coleopterans of both terrestrial and aquatic species. Dietary information is key to understanding life history and ecological strategies of little- known species, especially for their interactions with ecosystems which still remain pristine; it is important for the conservation of nature. Keywords. Diet, Prey, Ranita del Challhuaco, South America Introduction considered endemic to the province of Río Negro, Argentina, is found in Chile (Barrazo and Basso, 2018). The frog genus Atelognathus described by Lynch in A. nitoi inhabits temperate forests in the transition from 1978 was long recognised as a genus with distribution high prairie to lenga forest. Frogs are found under restricted to Chilean and Argentine Patagonia (Basso, 1998). There have been only a few studies stones quite far from the water in open areas above the on the biology of the genus Atelognathus, mainly forest and among forest vegetation under sticks and concerning systematic and morphological aspects. New leaves, usually near lagoons or streams (Meriggio et morphological and molecular approaches have reduced al., 2004; Díaz-Páez et al., 2011). In Lake Jeinimeni the number of species recognised in this genus from A. nitoi cohabits with Pleurodema bufonina Bell 1843 seven to five species: A. patagonicus Gallardo 1962; (Basso, 1998; Meriggio et al., 2004). The preferred A. praebasalticus Cei and Roig, 1968; A. reverberrii microhabitats of adults and juveniles are the most humid Cei, 1969; A. solitarius Cei, 1970 and A. nitoi Barrio, areas of the forest. 1973 (Barrazo and Basso, 2018). Most of these species The reproductive period extends from spring through are present in Argentina; only A. nitoi, which was long late summer (Meriggio et al., 2004). Release calls, an acoustic signal type in this species, seem to be strongly related only to the reproductive season. Reproduction and larval development occur in lentic environments 1 Laboratorio de Ecofisiología y Conservación de Herpetozoos, (Úbeda, 1999); after metamorphosis they quickly seek Departamento de Ciencias Básicas, Escuela de Educación, a wet shelter. As they grow, the juveniles disperse to Universidad de Concepción, Campus Los Ángeles, Casilla 341, Los Ángeles, Chile. new areas with similar characteristics, enduring greater 2 Departamento de Zoología, Facultad de Ciencias Naturales dryness (Meriggio et al., 2004). y Oceanográficas, Universidad de Concepción, Campus Amphibian feeding behaviour has been the focus of Concepción, Casilla 160-C, Concepción, Chile. numerous papers and has defined their role in terrestrial * Corresponding author. E-mail: [email protected] and aquatic ecosystems (Muñoz-Guerrero, 2007; © 2021 by Herpetology Notes. Open Access by CC BY-NC-ND 4.0. Arroyo, 2008), where they act as predators capable of 232 Nicza Alveal & Helen Díaz-Páez controlling many populations, especially invertebrates with greater relative importance for the aquatic form (Wells, 2007; Toledo et al., 2007). Multiple factors were odonate naiads and amphipod crustaceans. For the influence diet composition, including environmental littoral morph all prey were adult terrestrial arthropods changes (Solé et al., 2009), individual body size (Cuello et al., 2006). (Lima, 1998; Batista et al., 2011; Sugai et al., 2012), Our objective is to obtain basic knowledge about seasonality (Maragno and Souza, 2011) and hunting the diet composition of A. nitoi in Chile, including strategies (Maneyro et al., 2004). The trophic niche is identification of prey items, determination of abundance an important component of the natural history of species (N), frequency of occurrence (F) and relative importance and suggests ecological consequences (Anderson and index (IRI). Mathis, 1999), and there is a direct relationship between environmental conditions, habitat alterations and prey Materials and Methods distribution (Parker and Goldstein, 2004). Based on this environmental link, information about the trophic Our study took place in 2007 and 2010 spring-summer niche of the species can help to establish conservation seasons. 21 specimens of Atelognathus nitoi were strategies (Batista et al., 2011). collected from localities around lagoons in Chilean Trophic biology in the genus Atelognathus has Patagonia (Fig. 1), with permission from the Servicio only been reported in A. partagonicus, where two Agrícola y Ganadero (N° 6494, 27 December 2006). morphotypes have been documented for the species, The material analysed comes from four Patagonian a littoral morph and an aquatic morph, indicating a localities: La Tapera (44°38’S, 71°41’W; 1,041 m relationship between habitat and diet type. The items a.s.l.), Chile Chico (46°32’S, 72°00’W; 423 m a.s.l.), Figure 1. Habitat of the species of A. nitoi. A. La Tapera B. Cerro Castillo C. Chile Chico and D. Lago Jeinimeni. Diet composition of Atelognathus nitoi in Chilean Patagonia 233 Cerro Castillo (45°59’S, 71°52’W; 994 m), and Reserva mL precision test tube. With these data we calculated Nacional Lago Jeinimeni (46°50’S, 71°59’W; 730 m the aggregate percentage of volume and the number of a.s.l.) XI Región, Chile (Fig. 2). The environmental items consumed for each species (Litvaitis et al., 1994). conditions where we collected the specimens were We then determined an Index of Relative Importance similar, and due to the low number of individuals, we (IRI) (Powell et al., 1990) for each invertebrate taxon, grouped them without differentiating between locality for which we used the following formula: IRI = (%N + of origin to perform the trophic analyses. We captured %F + %V )/ 3, where %N is the aggregate numerical the amphibians between 13:00 h and 17:00 h. All percentage, %V is the aggregate percentage volume individuals were euthanised with 1% benzocaine and and %F is the percentage frequency of occurrence. This fixed in 10% formalin for subsequent preservation index allows comparing the relative importance that in 70% ethanol. All specimens were deposited in the each item represents in the total diet of the predatory Zoology Museum of the Universidad de Concepción species. (MZUC 36572–36575; 36577–36580; 36584–36586; The IRI values allowed establishing three categories 36589; 36404–36408; 36410–36411; 36414; 36418; of food importance: primary, secondary and tertiary, 36770–36772; 36763; 36767). We analysed the diet where the highest values of the index indicate the by dissecting the stomach between the cardias and the greatest importance of the food item. Since these are pylorus. We observed the stomach contents under a not continuous variables, the value of the median (2.73) stereo microscope and identified the different items to was prioritised over the value of the mean (3.67 ± 2.75) order or family. For each food item we recorded the total added to the standard deviation (Díaz-Páez and Ortiz, number and determined the volumetric valuation (V) 2003) in order to set the limits of each category (Table by calculating the volume of liquid displaced in a 0.01 1). Figure 2. Locations of A. nitoi in Chile included in the study: 1. La Tapera, 2. Cerro Castillo, 3. Chile Chico and 4. Reserva Nacional Lago Jeinimeni. 234 Nicza Alveal & Helen Díaz-Páez Table 1. AbundanceTable 1.and Abundance frequency and of preyfrequency items offound prey in items the stomachfound in contentsthe stomach of eight contents A. nitoi of eight(out ofA. 21nitoi examined). (out of 21 % N: examined). % N: Numerical percentage, f frequency of stomachs that had that prey, % F: Frequency of Numerical percentage,occurrence f frequencypercentage, of %V: stomachs Volumetric that hadpercentage that prey, and % RII: F: IndexFrequency of Relative of occurrence Importance. percentage, %V: Volumetric percentage and RII: Index of Relative Importance. Prey Item N f % V %F IRI Category Hexapods 1.1 Coleoptera Curculionidae 4 1 10 7.14 5.78 Primary Elateridae 4 2 8 14.28 7.49 Primary Carabidae (larva) 1 1 0.2 7.14 2.46 Tertiary Silvanidae (larva) 1 1 9 7.14 5.39 Secondary Tenebrionidae 1 1 1 7.14 2.73 Tertiary Scarabaeidae 1 1 5 7.14 4.06 Secondary Dytiscidae 2 2 16 14.28 10.12 Primary 1.2 Diptera Undetermined Diptera 1 1 0.5 7.14 2.56 Tertiary Tipulidae 1 1 1 7.14 2.73 Tertiary 1.3 Hymenoptera Ichneumonoidea 2 1 1 7.14 2.74 Secondary Crustacea 1 1 1 7.14 2.73 Tertiary Arachnida 1 1 0.5 7.14 2.56 Tertiary Results the OTUs Dytiscidae (10.12), Curculionidae (5.78) and Elateridae (7.49), all of the order Coleoptera.