Abstract Climate warming is driving widespread upslope range shifts in mountain amphibians, yet it remains unclear whether these expansions reflect population growth or spatial redistribution from lower elevations. Long-term monitoring of a mountain amphibian community has documented the upslope expansion of thermophilic species, declines of cold-adapted species, and persistent chytridiomycosis following severe population crashes. However, whether the low-elevation populations potentially supplying these colonists have undergone comparable changes in abundance has remained unknown. We analysed ten years of repeated surveys from 22 breeding sites using a hierarchical Bayesian multispecies N-mixture model that accounted for imperfect detection while estimating abundance trends and testing the effects of environmental conditions and the estimated prevalence of Batrachochytrium dendrobatidis (Bd) and Ranavirus (Rv). Most species remained stable or showed uncertain temporal trends, providing no evidence of a community-wide increase in abundance within historically occupied lowlands. A composite habitat gradient associated with water-body permanence, type and substrate was the only environmental predictor with a community-level abundance effect. Although the best-supported model excluded pathogen prevalence, an otherwise identical model including Bd remained competitive, whereas support for Rv was substantially weaker. Our results indicate that recent upslope colonisation is more consistent with spatial redistribution than with widespread increasing abundance across the elevational gradient, highlighting that range expansion alone can provide a misleading picture of population change.
Abstract Acoustic communication is a fundamental aspect of anuran reproductive behaviour, facilitating conspecific recognition and mediating intra- and inter-sexual interactions. The production and propagation of these signals are affected by environmental and constitutional factors. Among the latter, the relationship between body size and acoustic properties of anuran vocalisations has been studied across several taxa. In particular, an inverse correlation between body size and dominant frequency of calls prevails in many anuran species, so that larger individuals produce calls with lower dominant frequencies. Nevertheless, this allometric relationship has been explored to a limited extent at an inter-populational level within a species. The four-eyed frog ( Pleurodema thaul ) is extensively distributed in Chile, presenting geographical variation in the spectral and temporal characteristics of its advertisement call. We obtained data from 13 localities encompassing most of the species’ latitudinal range and evaluated the relationship between body size and dominant frequency within each population. Our analyses reveal that the allometric relationship does not follow a strictly uniform pattern at an intra-specific level, as not all populations comply with the negative correlation between these traits. The variability of this allometric relationship conforms with the lack of preferences for call spectral features in this frog and supports potential early evolutionary processes acting on the divergence of acoustic communication systems in anurans.
Abstract Teiidae is a monophyletic family of currently 170 lizard species with significant diversity in morphology, ecology, and reproductive modes, yet cytogenetic data remain limited, encompassing only a fraction of recognized species. Here, we provide the first chromosomal descriptions for five formally recognized species and two undescribed taxa across the genera Ameivula , Glaucomastix , and Kentropyx , based on conventional staining, Ag-NOR, and C-banding. We also describe new cytotypes for Ameivula ocellifera and Cnemidophorus cryptus . All analyzed Ameivula species, including two undescribed, exhibited a conserved karyotype of (FN = 86) with Ag-NORs located at a secondary constriction of pair 5, indicating marked chromosomal homogeneity despite deep lineage divergence. The parthenogenetic Cnemidophorus cryptus displayed a hybrid karyotype ( , FN = 51) characterized by a heteromorphic pair 1, corroborating its hybrid origin ( C. gramivagus . lemniscatus ) and extending its known range to Rondônia state. Glaucomastix itabaianensis presented (FN = 80), differing from the previously described G. littoralis ( ) and Kentropyx altamazonica also showed a plesiomorphic karyotype ( , FN = 50). These findings expand the cytogenetic dataset for Teiinae to 41 species, reinforcing the overall conservatism of diploid chromosome numbers within the subfamily while highlighting structural chromosomal variation with important implications for the systematics of these Neotropical lizards. Furthermore, the future application of additional chromosomal markers, such as repetitive DNA sequences, may uncover cryptic differentiation among species that otherwise exhibit conserved karyotypes.
Abstract The Rwenzori Mountains of Africa straddle the borders of Uganda and Democratic Republic of the Congo, and they are home to many endemic and threatened species. Among these species are three endemic skinks with a complicated taxonomic history that are known from very few specimens: Leptosiaphos meleagris (Boulenger, 1907), Panaspis burgeoni (de Witte, 1933) and P. helleri (Loveridge, 1932). These taxa and other congeners in these two closely related skink genera have undergone numerous taxonomic revisions throughout the 20th century, creating confusion about the composition of each genus, especially the Panaspis species. To assess the taxonomic status of P. burgeoni and P. helleri , we examined the morphology and geographic distributions of all known specimens, and compared them with each other and to L. meleagris . Although sample sizes are limited for the Panaspis taxa ( for each taxon), we conclude that P. burgeoni and P. helleri should be transferred to the genus Leptosiaphos and that they are junior subjective synonyms of L. meleagris based on extensive overlap in geography, morphology, and coloration that indicate insufficient diagnostic characters.
