Quaternary climatic fluctuations influence the demographic history of two species of sky-island endemic amphibians in the Neotropics

Colonization rather than fragmentation explains the geographical distribution and diversification of treefrogs endemic to Brazilian shield sky islands

“…Colonization of new areas is recovered as an important process for the evolution of the campo rupestre biota. This process also explains the contemporary geographical distribution of the genetic diversity in Vellozia auriculata bushes (Fiorini et al, 2019) and in the Alvarenga's treefrog (de Oliveira et al, 2021). Introgressive hybridization has also been reported for two Pithecopus monkey‐frogs (Magalhães et al, 2021).…”

“…The low‐latitude borders of Serra do Cabral, a disjunct montane unit west of ER (Figure 1), experienced high climatic instability and low suitability through time and may have acted as a continuous climatic barrier for taxa in the region. A corresponding genetic break is observed in the ledge treefrog (between the Cabral and the other lineages), as well as in other species such as the Alvarenga's treefrog ( Bokermannohyla alvarengai ), which does not occur in Serra do Cabral (de Oliveira et al, 2021), and the large‐eared rock frog, which has similar genetic structure to B. saxicola (Sabbag, 2013). In addition, the phylogeographical break between the central portion and the northern sky islands of SE was also observed for the large‐headed frog (Ramos et al, 2018).…”

“…Even though some similar spatial barriers can be highlighted among co‐distributed taxa in ER, they may not be related to the same temporal events associated with the diversification of B. saxicola . The congeneric Alvarenga's treefrog has a more recent diversification, with the northern and southern lineages diverging around 340 ka (de Oliveira et al, 2021). On the other hand, structure in the large‐eared rock frog coalesced in times comparable to our study, around 3 Ma (Sabbag et al, 2018).…”

“…However, there are still several shortfalls in the ecology and evolution of animals (Miola et al, 2021), even with the recent improvement in studies of anurofauna (e.g. de Oliveira et al, 2021; Magalhães et al, 2021). Our study adds one more piece to understanding the patterns and processes responsible for generating the ER's diversity and endemism.…”

“…For anurans, the ER houses more than 160 species, of which 30% are endemic (Leite, 2012) and often associated with campo rupestre (Leite, 2012; Leite et al, 2008). Only seven studies have examined the evolutionary history of these endemics at the phylogeographical level (Carvalho et al, 2021; de Oliveira et al, 2021; Magalhães et al, 2021; Nascimento et al, 2018; Ramos et al, 2018; Thomé et al, 2016; Thomé & Carstens, 2016).…”