The genus Atelognathus is composed of five species that occur in the southernmost regions of Argentina and Chile. It belongs to the Batrachylidae, one of the few endemic anuran families from Patagonia. More than 50 yr ago, it was concluded that A. reverberii had a diploid chromosomal complement of 2N = 26, a feature later reported for other congenerics. In this work, we describe the cytogenetics of all known species of Atelognathus (A. nitoi, A. patagonicus, A. praebasalticus, A. reverberii, and A. solitarius) and two additional undetermined populations. Unexpectedly, our analyses showed that all have a diploid chromosomal complement 2N = 24, which contrasts with conclusions of previous studies. We conclude that a karyotype of 2N = 24 is shared in Atelognathus as a derived condition within Batrachylidae. Additionally, we describe and discuss other cytogenetics characters (i.e., nucleolar organizer region location and C-banding patterns) of Atelognathus and related genera of Batrachylidae in an evolutionary framework.

Anurans communicate information during breeding activity to conspecifics mainly through acoustic signals, and different evolutionary forces may produce geographic variation in such communication systems. To understand which variables influenced geographic variation in the advertisement call of Dendropsophus nanus, a generalist species with a broad distribution in South America, we tested three nonexclusive hypotheses: geographic distance, environmental temperature, and body size. The advertisement call of this species consists of two note types: Type A, which functions in spacing among males in aggregations, and Type B, which may influence female choice. To determine the effect of the three explanatory variables on each note, we sampled nine populations in central and southern Brazil. We found that geographic distance and temperature were the main variables explaining variation in both notes. An exploratory analysis revealed differences in the advertisement call between populations in western and eastern localities. Because temperature was spatially structured, geographic distance may have produced variation in temperature along the longitudinal gradient, resulting in the observed variation in bioacoustic parameters among populations. Also, we observed that individuals in warmer localities were smaller than those from colder localities, and this difference in body size was correlated to the note repetition rate of Type A notes. Our findings indicate that variation in acoustic parameters may be an indirect result of temperature acting on body size. Thus, geographic variation in the advertisement call of D. nanus may be due to both neutral and selective processes.

Amphibian malformations occur naturally in wild populations. On Fernando de Noronha, Brazil, normal and dysmorphic Cururu Toads (Rhinella jimi) are found calling sympatrically in the same ponds. The very high incidence of dysmorphism (∼60%) that we found in this population confirms that the island remains a hotspot of malformed anurans. Considering that vocal communication is essential in the behavioral ecology in most anurans, we used distortion product otoacoustic emissions to assess the hearing sensitivity of normal and malformed male Cururu Toads and to compare the peak auditory sensitivity of each group to their call characteristics. Our results show that males with nontympanic malformations maintain a close match between the spectral features of their calls and the frequency tuning of their inner ears, much as the males in the normal population. In the face of rampant, wide-reaching somatic malformations, preserving their acoustic communication channel (as senders and as receivers) could allow dysmorphic toads to maintain their reproductive fitness.

Optimal escape theory states that animal prey counterbalance costs and risks before fleeing from predators. The theory seeks to explain the variation in distance between the predator and prey when the prey initiates flight (flight initiation distance [FID]). Although group living is commonly observed in the animal kingdom, it is not the predominant social behavior in squamates. Thus, studies of flight responses of grouped or social lizard species are very scarce. The Chilean lizard Liolaemus leopardinus is a highly social species and individuals of different age classes and sexes form social groups on rock outcrops where it is also common to observe solitary conspecifics. The flexible social behavior of L. leopardinus makes it a good model species to compare FID in solitary and grouped individuals. We measured escape behavior in solitary and grouped juvenile and adult L. leopardinus. We conducted trials on 61 solitary lizards and 14 grouped lizards (one focal individual in each group; maximum group size = 3). We found that FID, with basking habitat temperature (BHT) as a covariate, was significantly shorter in grouped L. leopardinus. This is a novel finding for a social lizard. The correlation between FID and distance to nearest refuge (DNR) was not significant, and DNR and BHT were not different between solitary and grouped lizards. In total, 38 lizards entered a refuge (29 solitary and 9 grouped individuals), mostly rock refuges. In this subsample, the correlation between distance fled and DNR was highly significant. The FID of those individuals that entered a refuge was not different than that of individuals that did not enter a refuge (with BHT as a covariate). Our finding that FID was shorter in grouped lizards was consistent with (1) a dilution effect that decreases individual risk of predation and/or (2) coincidental cooperation for indirectly enhanced threat detection. In the second interpretation, grouped lizards may spend less time vigilant and more time thermoregulating, waiting for some signal of enhanced predation risk by other individuals in the group.

The introductions of nonnative species can cause great change in the trophic dynamics of native species. Giant Gartersnakes, endemic predators in the Central Valley of California, are listed as threatened because of the conversion of their once vast wetland habitat to agriculture. Further contributing to this snake's changing ecology is the introduction of many nonnative prey species, resulting in a diet that is almost completely composed of nonnative species. In order to determine whether these snakes actively select their prey or simply consume what is abundant, we examined prey selection by adult Giant Gartersnakes in the context of what prey was available to each individual. Giant Gartersnakes selected a native anuran over nonnative anuran and fish species despite these nonnatives dominating the available species composition. These results contribute to understanding the mechanisms underlying Giant Gartersnake diets in the contemporary landscape and can lead to improved management of prey communities for Giant Gartersnakes and other native predators.

We studied nesting and reproductive ecology of critically endangered Gharials (Gavialis gangeticus) in the Narayani and Rapti rivers as well as ex situ breeding facilities in the Chitwan National Park in Nepal from 2001 to 2017. We located a total of 151 Gharial nests over 17 yr in sand banks along the Narayani (n = 94 nests) and Rapti (n = 57 nests) rivers and brought these nests to ex situ breeding facilities where eggs were artificially incubated. The number of nests (mean, 8.9/yr) showed an increasing trend over the years between 2001 and 2017. Nesting occurred within a narrow window of time (mean oviposition date, March 31) with onset of nesting varying by a maximum of 7 d between years (22–29 March). Similarly, eggs hatched from the first week of June through the first week of July (mean, June 15) after a mean incubation period of 76 d, with varying hatching success (mean, 60.5%). We did not find any correlation between incubation period and hatching success. Mean oviposition and hatching date both differed significantly among years probably due to annual variation in nesting cues. We found a significant positive correlation between clutch size and proportion of infertile eggs. Mean clutch size (32.3) and proportion of infertile eggs (mean, 10 eggs) both were significantly higher in clutches in Narayani than in Rapti; however, hatching success was significantly higher in clutches in Rapti. On average, nests had a circumference of 102.3 cm and a depth of 48.5 cm. Mean midriver depth (2.21 m) did not vary over the years but was higher in Narayani than in Rapti; however, mean depth of water nearest to the nest (1.15 m) varied among years and was higher in Rapti. Nests in Narayani were farther from the water's edge than nests in Rapti, suggesting local adaption of female Gharials to prevent flooding of nests owing to severe flooding in the Narayani. This is the first study to present long-term scientific information on nesting and reproduction of Gharials in Nepal. Such information will be pivotal in designing and implementing conservation programs as well as optimizing ex situ breeding practices for Gharials in Nepal.

We describe a new species of Adenomera from southwestern Amazonia. The new species corresponds to one of the acoustic patterns and morphotypes from Tambopata National Reserve (Adenomera “Forest Call II”), which was associated with the candidate species identified via molecular data as Adenomera sp. C in the phylogeny of the genus. The new species is distinguished from all congeners, except A. phonotriccus, by a unique advertisement call: calls are composed of complete pulses, i.e., separated by silent gaps, whereas those of remaining Adenomera species are composed of incomplete pulses (partly fused) or nonpulsed calls. The new species occurs in southeastern Peru and north central Bolivia, with two sympatric records with A. chicomendesi. The taxonomic status of two candidate species (sp. D and sp. T) of the A. andreae clade in southwestern Amazonia still needs to be addressed by the acquisition of additional phenotypic and molecular data.

Philippine False Geckos (genus Pseudogekko) are secretive, delicate, slender-bodied, arboreal members of an obligate forest specialist clade that is substantially more species diverse than previously assumed. Over the last century, few species were added to this Philippine endemic genus. During the last decade, however, revisionary studies have resulted in the recognition of six new species. Several of these appear to be rare, have restricted geographic ranges, or exhibit patchy, fragmented areas of occurrence. In this study we report on the discovery of a second Luzon Island species in the P. brevipes complex, a clade in which members typically have diminutive bodies. Although the new species is readily diagnosed from all congeners, we estimated its systematic affinities with a phylogenetic analysis of DNA sequence data and confirm that it is nested within the P. brevipes clade. The new species constitutes an exception to the general appearance of other members of the P. brevipes complex, in that it has a relatively heavy-bodied, robust stature, separating it phenotypically from all members of the group. Our new species constitutes the second Luzon lineage in this group of rainforest species (considered previously to be restricted to the Negros-Panay and Mindanao Pleistocene aggregate island complexes [PAICs] in the central and southern landmasses of the archipelago). Given the lack of available biodiversity information for the major remaining forests of the Bicol Peninsula, which necessarily come from targeted faunal surveys, the new species' conservation status cannot yet be assessed. In light of the highly fragmented nature of forested habitats of southern Luzon, we suspect the new species might be vulnerable to extinction as a result of habitat loss.

We describe a new species of the genus Abronia from the La Sepultura Biosphere Reserve in western Chiapas, México. The new species is known only from the vicinity of the type locality in the Sierra Madre de Chiapas. It is readily distinguished from all congeners by the following combination of characters: lack of protuberant or spine-like supra-auricular scales, lack of protuberant or casque-like posterolateral head scales, 30–35 transverse dorsal scale rows, lateralmost row of ventral scales enlarged relative to adjacent medial row, dorsum brown with 8–10 transverse dark crossbands, and dark lateral bar on the neck extending from the shoulder to near the auricular opening. We tentatively assign the new species to the subgenus Lissabronia pending the availability of a robust, comprehensive molecular phylogeny for the genus. We discuss regional Abronia biogeography and comment on the conservation implications of our discovery for the imperiled highland forests of the Sierra Madre de Chiapas, a globally important center of endemism.

Wallace's and Lydekker's Lines both describe important biogeographic barriers in the Indo-Australian Archipelago, with Wallace's Line demarcating the boundary of the Greater Sunda Shelf and Lydekker's Line indicating the edge of the Sahul continental shelf. Despite their similarities, Wallace's Line has been much more heavily studied than has Lydekker's Line, yet provides an interesting system for testing the source of fauna into eastern Wallacea. New collections of Northern Water Dragons, Tropicagama temporalis, from several islands in Maluku, eastern Indonesia now allow for an assessment of the phylogeography of the species and the ability to test if New Guinean or Australian populations served as the source for over-water dispersal across Lydekker's Line into Maluku. We collected specimens from remote islands in eastern Indonesia, sequenced the mitochondrial ND2 gene, and aligned the data to previously sequenced specimens on GenBank. We conducted several phylogenetic and divergence time analyses to investigate the source population and timing of dispersal. We found low genetic diversity among the islands in Maluku, and these samples showed little genetic divergence from New Guinea samples. The New Guinea and Maluku populations diverged less than 1 million years ago (Ma) and together diverged from the Australian population between 2.3 and 4.7 Ma. These results, along with patterns in other taxa, illustrated that, despite Australia's close geographic proximity to many of the islands in southeastern Indonesia, New Guinea has been the more frequent source of Wallacean fauna from Sahul.