Biology subjects

dos Santos, E. M.

Publications and source records attributed to dos Santos, E. M..

2 recordsLinked to original sources

bioRxiv2025

When and where to find the tiny creatures: environmental predictors of the abundance of a miniaturized frog species from Northeast Brazil

Amphibians are the most vulnerable terrestrial vertebrates to environmental changes, primarily due to their permeable skin and dependence on water for reproduction. In miniaturized frogs, sensitivity to changes in ecological factors related to humidity may be particularly critical due to their high surface-to-volume ratio, which makes them more susceptible to desiccation. To test this hypothesis, we evaluated the influence of environmental variables on the abundance of calling males of Adelophryne nordestina, a small miniaturized frog with direct development inhabiting the Atlantic Forest leaf litter in northeastern Brazil. We surveyed calling males of A. nordestina over nine months across four transects, each containing 25 survey points, totaling 100 study sites. We employed a Negative Binomial N-Mixture Model to estimate the abundance of calling males and assessed the effect of environmental parameters. Our results indicate that estimated mean detection probability was 0.03, and mean abundance among sites was 85.90. Precipitation, temperature, leaf litter depth, and canopy cover significantly influenced the number of calling males in the study area. We suggest that, as a terrestrial, miniaturized, and direct-developing species, changes in environmental parameters affecting microhabitat humidity impact its reproductive activity. Our findings contribute to the understanding of miniaturized frog ecology and the potential impacts of environmental disturbances on this group.

ecology↗

bioRxiv2020

The West African lungfish provides insights into the evolution of tetrapod tail regeneration

Salamanders, frog tadpoles, and diverse lizards have the remarkable ability to regenerate tails. Paleontological data suggests that this capacity is plesiomorphic, yet when the developmental and genetic architecture of tail regeneration arose is poorly understood. Here we show morphological and molecular hallmarks of tetrapod tail regeneration in the West African lungfish Protopterus annectens, a living representative of the sister group of tetrapods. As in salamanders, lungfish tail regeneration occurs via formation of a proliferative blastema and restores original structures, including muscle, skeleton and spinal cord. In contrast to lizards and similar to salamanders and frogs, lungfish regenerate spinal cord neurons and reconstitute dorsoventral patterning of the tail. Similar to salamander and frog tadpoles, Shh is required for lungfish tail regeneration. Through RNA-seq analysis of uninjured and regenerating tail blastema, we show that the genetic program deployed during lungfish tail regeneration maintains extensive overlap with that of tetrapods, with the upregulation of genes and signaling pathways previously implicated in amphibian and lizard tail regeneration. Furthermore, the lungfish tail blastema showed marked upregulation of genes encoding post-transcriptional RNA processing components and transposon-derived genes. Our results show that developmental processes and genetic program of tetrapod tail regeneration were present at least near the base of the sarcopterygian clade and establish the lungfish as a valuable research system for regenerative biology.

evolutionary biology↗