Rev. Mus. Argentino Cienc. Nat., n.s. 22(1): 1-6, 2020 ISSN 1514-5158 (impresa) ISSN 1853-0400 (en línea) Hylid or microhylid? No evidence for the occurrence of Trachycephalus mesophaeus (Anura, Hylidae) in Argentina Julián FAIVOVICH & Agustín J. ELIAS-COSTA División Herpetología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”--CONICET, Ángel Gallardo 470, C1405DJR Buenos Aires, Argentina. E-mail: [email protected] Abstract: A recent publication reported the Atlantic Forest endemic hylid Trachycephalus mesophaeus for the Chacoan ecoregion in Argentina. In this paper, we analyzed the voucher specimen and showed that it is a mis- identified specimen of the Asiatic microhylid Kaloula pulchra, a species commonly commercialized in the pet trade worldwide. Therefore, there is no evidence for the occurrence of T. mesophaeus in Argentina. Key words: Hylidae, Hylinae, Lophyohylini, Microhylidae, Kaloula, bizarre taxonomy Resumen: Hílido o microhílido? No hay evidencia de la presencia de Trachycephalus mesophaeus (Anura, Hylidae) en Argentina. Una publicación reciente reportó al hílido endémico del Bosque Atlántico Trachycephalus mesophaeus para la ecoregión Chaqueña en Argentina. En este trabajo, analizamos el espécimen de referencia y demostramos que se trata de un ejemplar incorrectamente determinado del microhílido asiático Kaloula pulchra, una especie comercializada a nivel mundial. De esta forma, no existe evidencia para considerar que T. mesophaeus esté presente en Argentina. Palabras clave: Hylidae, Hylinae, Lophyohylini, Microhylidae, Kaloula, taxonomía bizarra _____________ INTRODUCTION 2010), in the provinces of Chaco, Corrientes, Entre Ríos, Formosa, Jujuy, Misiones, Salta, The hylid lophyohyline genus Trachycephalus Santa Fe, and Santiago del Estero (Vellard, 1948; Tschudi, 1838 includes 17 species (Blotto et al., in Cei, 1956, 1980; Martínez-Achenbach, 1961; press) distributed from Mexico to central-eastern Lavilla and Scrocchi, 1988). This species has a Argentina (Frost, 2020). Faivovich et al. (2005) wide distribution, reaching Central America recovered the type species of Trachycephalus, (Frost, 2020), and still requires a considerable T. nigromaculatus Tschudi, 1838, nested among taxonomic effort to elucidate how many different species of Phrynohyas Fitzinger, 1843, and rede- species are included under the name (Lavilla et fined Trachycephalus to also include all species al., 2010; Ron et al., 2016; Ferraro et al., 2018; formerly included in that genus. Blotto et al., in press). Two species of Trachycephalus have been considered to be present in Argentina: Trachy- THE NEW RECORD cephalus dibernardoi Kwet & Solé, 2008 and T. typhonius (Linnaeus, 1758). The former Recently, Garcia-Marsà et al. (2020) reported was initially reported by Carrizo (1989) as a third species of Trachycephalus for Argentina, Phrynohyas imitatrix (Miranda-Ribeiro, 1926) T. mesophaeus (Hensel, 1867), based on a single for the interior Atlantic Forest in the province specimen (CFA-An-88; Scientific collection of of Misiones, and subsequently considered to be Fundación de Historia Natural “Félix de Azara”, T. dibernardoi by Kwet & Solé (2008). More re- amphibians; Ciudad de Buenos Aires, Argentina) cently, Blotto et al. (in press) suggested that the informed as collected in Las Lomitas, province distinction between both species needs to be re- of Formosa, on October 3, 1986. Trachycephalus assessed. Trachycephalus typhonius has been mesophaeus (Fig. 1 A-D) is a species known to recorded in Argentina (as Phrynohyas venulosa occur in the Atlantic Forest of Southeastern and or Trachycephalus venulosus; see Lavilla et al., Eastern Brazil, from the states of Rio Grande 2 Revista del Museo Argentino de Ciencias Naturales, n. s. 22(1), 2020 do Sul to Pernambuco (e.g., Kwet et al., 2010; pads, despite being an adult male as revealed by Haddad et al., 2013). Garcia-Marsà et al. (2020) the dark-colored vocal sac (present in all species identified the specimen explicitly based on color of Trachycephalus). (6) Presence of an expan- pattern, and, very likely (see below) on the fact ded, spade-like inner metatarsal tubercle (oval, that the specimen had a label identifying it as not expanded in Trachycephalus). (7) Short “Trachycephalus sp.” The authors pondered the hindlimbs (hindlimbs proportionally larger in possibility that it could belong to “a still unk- Trachycephalus). Briefly: the specimen does not nown population of the T. typhonius complex”. even remotely look like a hylid, nor is it similar to However, as they concluded that the specimen any other anuran species occurring in Argentina. showed “all morphological attributes of T. me- The study of the specimen CFA-An-88 (Fig. sophaeus”, they considered it to belong to this 1 E, F), besides corroborating all the characters species. that are evident in the published photographs, Once they established the identification of indicates that the specimen lacks maxillary and the specimen, Garcia-Marsà et al. (2020) discus- premaxillary teeth, and that it has two noticea- sed possible reasons why T. mesophaeus has not ble palatal folds. This combination of characters been collected in recent years in Argentina. They is only known to occur in anurans of the families considered that the species might be difficult to Brevicipitidae and Microhylidae (Parker, 1934; find, and as the Chacoan ecoregion is still poorly Laurent, 1986). explored, they hypothesized that perhaps there From a purely taxonomic perspective, the are still healthy populations of T. mesophaeus in specimen in question cannot be associated with the Chacoan ecoregion. Alternatively, they dis- Brevicipitidae as it lacks the very characteristic cussed the possibility that the species has been body shape and reduced mouth of the species in locally extinct due to the substantial degradation this family (see Channing & Rödel, 2019), thus of this ecoregion. Garcia-Marsà et al. (2020) also pointing at the widely-distributed, diverse family discussed the biogeographic significance of their Microhylidae (690 species; Frost, 2020). This finding of an Atlantic Forest-endemic species in family currently includes 13 (de Sá et al., 2012; the transition zone of the humid and dry portions Peloso et al. 2016) or 12 subfamilies (Tu et al. of the Chacoan ecoregion. They considered that 2018; Streicher et al., 2020). Although there has it was not uncommon, based on the evidence of been considerable progress in defining its major past connections between the Atlantic Forest and clades, recent discussions on the phylogenetic the Amazon basin. They further suggested that relationships of the family have barely referred their finding of a “relictual population” of T. me- to phenotypic evidence or taxonomic aspects. sophaeus could reflect the past, widespread dis- For this reason, the taxonomic identification of tribution of gallery forests and associated fauna. a microhylid without locality data could be cha- llenging. Fortunately, this was not the case, as THE SPECIMEN this specimen belongs to one of the microhylid species most commonly available in the pet tra- The photographs provided by Garcia-Marsà de: Kaloula pulchra Gray, 1831. et al. (2020: fig. 2) of the specimen that they Among microhylids, the specimen is attri- identified as T. mesophaeus show a frog that has butable to the microhyline Kaloula pulchra the following remarkable characters (all the in- due to the combination of the following charac- formation for Trachycephalus is from Duellman, ters (compare Figs. 1 E, F and 1 G, H): Snout- 1971; Paolillo & Cerdá, 1981; Pombal et al., 2003; vent length of 50–60 mm (the specimen is quite Gordo et al., 2013; Nunes et al., 2013; Blotto et contorted and it is difficult to make a precise al., in press): (1) A large, darkly-pigmented single measurement) congruent with the size inter- subgular vocal sac (vocal sacs in Trachycephalus val reported for adult males of this species, are paired, bilateral or, less commonly, bilobular). 54–72 mm, vs. smaller SVL in adult males of (2) Absence of a tympanic membrane (all species Adelastinae, Chaperininae, Hoplophryninae, of Trachycephalus have a prominent tympanic Melanobatrachinae, and most species of Astero- membrane). (3) Foot and hand webbing basal phryinae, Cophylinae, Gastrophryninae, and or absent (all species of Trachycephalus have a Scaphiophryninae); robust body; head wider considerable amount of foot webbing, and evi- than long with truncated snout (vs. acute, sub- dent hand webbing). (4) Non-expanded discs triangular in Gastrophryninae, Kalophryninae (all species of Trachycephalus have prominent and Otophryninae); tympanic membrane ab- discs in hands and feet). (5) Absence of nuptial sent; supratympanic fold present; absence of Faivovich & Elias-Costa: Hylid or microhylid? 3 Fig. 1. A–B: Adult female of the hylid Trachycephalus mesophaeus LGE 10538 (Brazil: Rio Grande do Sul: Terra de Areia). C: Detail of nuptial pad, and D: gular region in ventral view of an adult male T. mesophaeus LGE 22305 (Brazil: São Paulo: Ubatuba). Vocal sacs are paired, lateral, and almost entirely restricted to the post- tympanic region, with little subgular development, as evidenced by the lack of dark pigmentation in the area. E–F: Adult male of the microhylid Kaloula pulchra (CFA-An-88), the specimen identified as T. mesophaeus by Garcia-Marsà et al. (2020). G–H: Adult male Kaloula pulchra MACN-He 39171 (pet trade), a properly fixed and preserved specimen. Scale bars: 1 cm. Abbreviations not used in the main text: LGE: