The inappropriate delimitation of species may lead to inflated species lists, with implications for biodiversity research, management, and conservation. In this paper, we reassess and discuss the taxonomic status of the lizards Liolaemus montanezi Cabrera and Monguillot, 2006 and L. cinereus Monguillot et al., 2006, members of the L. boulengeri species group (Liolaemidae). These taxa have been treated as syntopic and endemic to a hyper-arid desert from central‑western Argentina, but are hereafter considered synonyms. Evidence supporting their conspecificity relies on the comparison of morphological characters, including scale counts, morphometry, and body‑shape traits, which showed extensive overlap. Further, a comprehensive phylogenetic analysis comprising 84 terminals from the L. boulengeri group (plus seven outgroups) and 155 morphological characters (34 continuous and 121 discrete) recovered L. montanezi and L. cinereus as sibling species with no autapomorphic traits. These lizards coexist in a small area of approximately 2 km² where no clear structural or ecological differences were detected. The essentially identical ecology of L. montanezi and L. cinereus is interpreted as an additional index of their status as a single taxonomic entity. With the proposed synonymy, the name L. montanezi has priority over L. cinereus, and species accounts of the L. boulengeri species group should be updated accordingly.

La inadecuada delimitación de especies puede conducir a una inflación de las listas taxonómicas con implicaciones para la investigación, el manejo y la conservación de la biodiversidad. En este trabajo, reevaluamos y discutimos el estatus taxonómico de las lagartijas Liolaemus montanezi Cabrera y Monguillot, 2006 y L. cinereus Monguillot et al., 2006, miembros del grupo de L. boulengeri (Liolaemidae). Estos taxones han sido tratados como sintópicos y endémicos de un desierto hiperárido del centro-oeste de Argentina, pero en lo sucesivo se considerarán sinónimos. La evidencia que respalda su sinonimización proviene de la comparación de caracteres morfológicos, incluidos recuentos de escamas, morfometría y rasgos de la forma del cuerpo que mostraron una notable superposición. Además, en un análisis filogenético amplio que incluyó a 84 terminales del grupo L. boulengeri (más 7 grupos externos) y 155 caracteres morfológicos (34 continuos y 121 discretos) L. montanezi y L. cinereus fueron recuperadas como especies hermanas sin rasgos autapomórficos. Estas lagartijas coexisten en una pequeña superficie de aproximadamente 2 km² donde no se detectaron claras diferencias fisionómicas ni ecológicas. La ecología esencialmente idéntica de L. montanezi y L. cinereus es interpretada como un indicador adicional de su estatus como entidad taxonómica única. Con la sinonimia propuesta, el nombre L. montanezi tiene prioridad sobre L. cinereus, y las enumeraciones de especies del grupo de L. boulengeri deben actualizarse como corresponde.

The auditory sensitivity of frogs Discoglossus (Alytidae) was measured and compared with the known spectral characteristics of their vocalizations, to assess evolutionary patterns of sound communication in these primitive anurans. Multi-unit recordings in the Torus semicircularis of 6 D. pictus, and 2 D. galganoi show two regions of enhanced sensitivity, below 0.5 kHz and at ca. 1.6 kHz, with minimum thresholds at ca. 40 and 50 dB SPL, respectively. The high frequency sensitivity region is tuned to frequencies higher than the calls reported for this genus, with dominant frequencies below 1 kHz. These audiogram characteristics were similar to those measured in a former study in Iberian Alytes toads. However, auditory thresholds to calls of Alytidae were higher in Discoglossus relative to those measured in A. cisternasii, A. obstetricans and A. dickhilleni in response to vocalizations of one Discoglossus and two Alytes species. The relatively high auditory thresholds of Discoglossus, together with the low amplitude of their vocalizations and the detuning between call spectra and auditory sensitivity restrict their sound communication to short distances. Such mismatch is likely a derived trait in the evolutionary history of the genus, as occurs in other anuran groups.

Most records of camallanid species are from fish, being poorly studied in South American turtles. This paper reports several species of Camallanus and one Serpinema parasitizing freshwater turtles in Argentina. We also describe two new nematode species of Camallanus from the Chaco Side-necked turtle Acanthochelys pallidipectoris, the Hilaire's Side-necked turtle Phrynops hilarii, and the Black Spine-neck Swamp turtle Acanthochelys spixii. These two new nematode species differ from their previously described congeners mainly in the shape of the buccal capsule, spicules, number and distribution of caudal papillae in males, and number of mucrons in females. We provide 18S rDNA sequences of the new species of Camallanus and Camallanus sp. and report interspecific distances for the Camallanus species. Further, we report C. emydidius from Trachemys dorbigni and Camallanus sp. and Serpinema sp. from Kinosternon scorpioides, constituting the first parasitological records for these turtles in Argentina. Also, C. pallidipectoris sp. nov. is the first global parasitological report for the endangered turtle A. pallidipectoris.

Vocalizations can vary in relation to individuals and species, and their function is highly dependent on social context. Parental care can influence calling behavior because of the energetic constraints imposed by performing both tasks simultaneously. However, little is known about the association of acoustic traits with parental care across species that continue to call and accumulate multiple clutches while attending their offspring. In this study, we quantified variation in temporal and spectral call traits in relation to paternal care under natural field conditions in a glassfrog species (Centrolenidae) from the Costa Rican Atlantic rainforest. Specifically, we explored if the calls of males observed in egg-attendance activities differ from those of single individuals not displaying parental care in their call rate, call duration, and dominant frequency. In a second series of analyses generated by additional field observations, we assessed variation in the same acoustic traits in relation to call type by comparing the call of single non-attending males (advertisement call) with that of individuals participating in male–male, long-range acoustic disputes (aggressive call). Our results demonstrate that adult males engaged in egg-attendance or territorial encounters have a different call rate but not dominant frequency or call duration relative to individuals not engaged in these activities. Our findings show that non-attending individuals call more often than attending individuals, but that individuals involved in male–male interactions exhibited the highest call rates overall. Based on these results, we discuss the hypothetical role of call rate as an indicator of male condition with respect to both male–male and male–female interactions. The findings of this study are expected to be helpful for future taxonomic assessments of Hyalinobatrachium talamancae and increase our understanding on the evolution of bioacoustics and natural history aspects associated with paternal care and territoriality in neotropical frogs.

Although data from the internal oral anatomy and chondrocranium of anuran larvae can be used to resolve taxonomic questions, there is no information on these characteristics for species of the Dendropsophus marmoratus group. Herein, we provide a complete description of the tadpole of D. soaresi, presenting additional information about the external larval morphology and unpublished data on internal oral anatomy and chondrocranium of specimens collected in the state of Piauí, northeastern Brazil. The measurements and morphological characters were based on 10 tadpoles in stages 35–36. Two tadpoles in stage 36 and one in stage 35 were dissected for analysis of the internal oral anatomy. To describe the chondrocranium, six stage 36 tadpoles were cleared and double-stained. We find small differences concerning the original description of the external morphology, such as body shape, oral disk size, shape and height of the fins, and position of the vent tube. We also present additional information on coloration in life and morphometric details. Similar to other species of the genus, the tadpole of D. soaresi has a reduced number of structures in the buccopharyngeal region, although presenting lingual papillae and a rounded cornified structure in the prenarial arena. Also, D. soaresi presents a set of chondrocranial traits that are not found in other species of the genus and are possible synapomorphies for the D. marmoratofus group. This variation highlights the potential of larval morphology as a source of evidence for Dendropsophus systematics. However, additional research on the internal anatomy of Dendropsophus species, especially those of the D. marmoratus group, are essential to clarify the phylogenetic relationships of the genus.

An important goal in ecology is to identify variables that influence species occurrences, as this influences the potential distribution and population size. In this study, we investigated the influence of abiotic factors in stream habitats on the occurrence and abundance of the insular endemic frog Hylodes fredi on Ilha Grande, off the southeast coast of Brazil. We collected data on six physical and chemical variables from 30 stream habitats, all in ombrophilous Atlantic Forest. We used generalized linear models with binomial and zero-inflated Poisson distributions to identify the abiotic variables that best predict the occurrence and abundance of H. fredi among streams. The results indicated that light intensity predicted the occurrence of H. fredi among streams, possibly due to its influence on reproductive activity in this diurnal species. The best Poisson model did not include any abiotic variables, probably due to the lack of the variability of abundance records. This is possibly a consequence of the naturally low density of hylodid species and/or the influence of factors not included in the models (e.g., pollution). Hylodes fredi is restricted to a 193 km² island from an endangered biome, found only in clean, well illuminated streams, with luminous incidence of at least 400 lux. Given the restricted occurrence of H. fredi, both geographically and in terms of habitat requirements, the species should be considered “Endangered,” according to the IUCN Red List criteria.

Um objetivo importante na ecologia é identificar variáveis que influenciam na ocorrência das espécies, uma vez que esta influencia a distribuição potencial e o tamanho populacional. Neste estudo, investigamos a influência de fatores abióticos de riachos sobre a ocorrência e abundância da rã endêmica insular Hylodes fredi na Ilha Grande, litoral sudeste do Brasil. Coletamos dados de seis variáveis físicas e químicas de 30 riachos, todos encontrados na região ombrófila de Mata Atlântica. Usamos modelos lineares generalizados com distribuições de Poisson binomial e zero inflacionada, a fim de identificar quais variáveis abióticas melhor preveem a ocorrência da espécie entre os riachos e sua abundância. Os resultados indicaram que a intensidade de luz prediz a ocorrência de H. fredi ao longo dos riachos, possivelmente devido à sua influência na atividade reprodutiva dessa espécie diurna. O melhor modelo de Poisson não encontrou influência de nenhuma variável abiótica, provavelmente em decorrência da falta de variabilidade nos registros de abundância. Esta é uma possível consequência da baixa densidade natural das espécies Hylodidae e/ou a abundância das espécies é influenciada por outros fatores não avaliados pelos modelos (por exemplo, poluição). Hylodes fredi é uma espécie restrita a uma ilha de 193 km² de um bioma ameaçado, encontrada apenas em córregos limpos e bem iluminados, com pelomenos 400 lux de incidência luminosa. Por conta da ocorrência restrita, tanto geograficamente quanto em requerimento do habitat, a espécie deve ser considerada uma espécie “Ameaçada”, de acordo com os critérios da Lista Vermelha da IUCN.