Neotropics as a Cradle for Adaptive Radiations.

Neotropical ecosystems are renowned for numerous examples of adaptive radiation in both plants and animals resulting in high levels of biodiversity and endemism. However, we still lack a comprehensive review of the abiotic and biotic factors that contribute to these adaptive radiations. To fill this gap, we delve into the geological history of the region, including the role of tectonic events such as the Andean uplift, the formation of the Isthmus of Panama, and the emergence of the Guiana and Brazilian Shields. We also explore the role of ecological opportunities created by the emergence of new habitats, as well as the role of key innovations, such as novel feeding strategies or reproductive mechanisms. We discuss different examples of adaptive radiation, including classic ones like Darwin's finches and Anolis lizards, and more recent ones like bromeliads and lupines. Finally, we propose new examples of adaptive radiations mediated by ecological interactions in their geological context. By doing so, we provide insights into the complex interplay of factors that contributed to the remarkable diversity of life in the Neotropics and highlight the importance of this region in understanding the origins of biodiversity.

Environment rather than character displacement explains call evolution in glassfrogs.

The acoustic adaptation hypothesis (AAH) and ecological character displacement (ECD) are two potential mechanisms shaping call evolution that can predict opposite trends for the differentiation of signals. Under AAH, signals evolve to minimize environmental degradation and maximize detection against background noise, predicting call homogenization in similar habitats due to environmental constraints on signals. In contrast, ECD predicts greater differences in call traits of closely related taxa in sympatry because of selection against acoustic interference. We used comparative phylogenetic analyses to test the strength of these two selective mechanisms on the evolution of advertisement calls in glassfrogs, a highly diverse family of neotropical anurans. We found that, overall, acoustic adaptation to the environment may outweigh effects of species interactions. As expected under the AAH, temporal call parameters are correlated with vegetation density, but spectral call parameters had an unexpected inverse correlation with vegetation density, as well as an unexpected correlation with temperature. We detected call convergence among co-occurring species and also across multiple populations from the same species in different glassfrogs communities. Our results indicate that call convergence is common in glassfrogs, likely due to habitat filtering, while character displacement is relatively rare, suggesting that costs of signal similarity among related species may not drive divergent selection in all systems.

Description of two calls of Eleutherodactylus rubrimaculatus (Anura: Eleutherodactylidae) in Chiapas, Mexico.

Frogs of the genus Eleutherodactylus are direct developing frogs grouped into five subgenera and 192 species, with a geographic distribution primarily centered in the Caribbean (Padial et al. 2014). Eleutherodactylus species inhabit a variety of environments such as tropical and temperate forests, and scrub, where they occupy different microhabitats including caves, floors rich in leaf litter, cracks and cavities of limestone and volcanic outcrops (Reyes-Velasco et al. 2015). Mexico harbors 33 species of Eleutherodactylus (AmphibiaWeb 2018), most of them distributed in central-western and southwestern Mexico (Reyes-Velasco et al. 2015).

A morphological database for Colombian anuran species from conservation-priority ecosystems.

Species traits provide a strong link between an organism's fitness and processes at community and ecosystem levels. However, such data remain scarce for amphibians in the Neotropics. Colombia is the country with the highest number of threatened amphibians and the second greatest number of amphibian species worldwide. We present a data set containing eight morphological traits for 4,623 museum specimens of the seven largest collections in the country corresponding to 293 species of 14 families. The number of measured specimens per species ranged from 1 to 118 individuals with a median of 8 individuals per species. Overall, this database gathered morphological information for 37.6% of Colombian anuran diversity. Species measured were mainly distributed in the high Andean forest, the páramo, and wetland ecosystems, and was part of a national initiative led by the Instituto Alexander von Humboldt. The morphological traits were selected on the basis of their role in species' responses to environmental variability and their contributions to ecosystem processes. These traits were related to habitat use, (forearm length, tibia length, femur length, foot length, and foot webbing), predation and food chains (head width and mouth width), and nutrient recycling (snout-vent length). We expect this data set will be used in studies on functional diversity in amphibians and the development of conservation planning for these taxa. No copyright or proprietary restrictions are associated with the use of this data set other than citation of this Data Paper.