Aim: The disjunct distributions of freshwater organisms along coastal drainages are usually explained by paleodrainages formed during sea-level retreats that connected currently isolated basins, or by river capture from tectonic adjustments between adjoining watersheds. We evaluate the relative importance of these events on the genetic variation of freshwater fishes inhabiting the Serra do Mar in eastern Brazil, a region with steep mountains and pronounced bays.
Location: Coastal river drainages in southeastern Brazil.

Taxon: Catfishes of the Trichomycterus alternatus group.

Methods: We tested the effects of paleolandscape connections (GIS-reconstructed paleodrainages and putative river captures) on the genetic structure (mitochondrial and nuclear markers) of T. alternatus from 15 drainages using phylogenetic reconstructions, lineage delimitation methods and analyses of molecular variance.
Results: Trichomycterus alternatus is monophyletic and comprised of three main lineages: two restricted to the basin at its northernmost distribution and another broadly distributed to the south. In the latter, seven major cytb clades were geographically compatible with the eight paleodrainages, with three incongruences matching river captures previously described for the Guanabara Bay (GB). Shared haplotypes among isolated rivers flowing into GB provide the first molecular evidence of the ‘Rio de Janeiro’ paleoriver.

Main conclusions: Dispersal via paleorivers is an important process, but it is not enough to recover the most recent dispersive events. Therefore, integrating both paleo-riverine configuration (GIS-based) and localized river captures (geological studies) is crucial to reveal the role of past geological and climatic events on the distribution of freshwater organisms. Taken together, these two factors significantly explained a high portion T. alternatus genetic structure along coastal drainages, revealing a paleolandscape scenario that may have been used by other freshwater Atlantic Forest taxa.

All methodology used for sampling collection and processing is described in the Materials and Methods session of the original manuscript.

This dataset contain the following files:

1) Two '.fas' files with the sequences (one for cytb and another for  its1) used for the phylogenetic and phylogeographic reconstructions used in this study.

2) One '.trait' file was used to for defining lineages for every sequenced used in the phylogenetic reconstruction.

3) A '.tree' file  with the concatenated species tree generated in the software STARBEAST  as described in the 'phylogenetic analyses' section of the manuscript.

4) A '.zip' file containing all the relevant files, scripts and results from the species delimitation methods.

5) A '.md' file containing a README file describing the step-by-step protocol for the paleodrainages reconstructions.

Please, contact smaialimag@gmail.com or waldirmbf@gmail.com should any question arise.