Aim
The Neotropical region is the most biodiverse in the world, and several hypotheses have been proposed to explain this pattern. Among them, the most prominent are the hypotheses of biotic interchange between domains, climatic refugia during the Pleistocene and geomorphological changes during the Miocene, such as the reorganization of the Brazilian Central Plateau. The tarantula genus Dolichothele Mello-Leitão, 1923 comprises 10 species occurring in South America's open habitats and humid forests. Understanding the relationships among these species would allow testing hypotheses regarding drivers of diversification in the Neotropical region.
Location
The Neotropical region.
Taxon
Dolichothele (Araneae: Theraphosidae).
Methods
Seven of the then currently known species in Dolichothele were sampled, and Genotype-by-Sequencing was used to propose new phylogenetic hypotheses, delimit species through demographic and genetic structure analyses, and explore its biogeographic history through ancestral area reconstruction.
Results
Two well-supported phylogenetic hypotheses, one undescribed species from Campos rupestres, and one lineage that should be further investigated were proposed. The genus first diversified in a Cerrado + Caatinga environment, followed by two periods of diversification: one in the late-Miocene (~9 Myr), related to the origin of two Caatinga species and main lineages from different domains (Cerrado and Atlantic Forest), and another in the Pliocene (~3.7 Myr), related to diversification of these main lineages, possibly influenced by reconfigurations of the Brazilian Central Plateau and geological barriers in the Atlantic Forest.
Main Conclusions
The biogeographic history of Dolichothele is characterized by transitions across major domains and diversification within them during the Miocene and Pliocene. Results suggest that the genus first diversified in seasonal environments in the Neotropics and later colonized humid forests. Moreover, geomorphological drivers might have been more relevant to Dolichothele diversification than climatic ones, given the group's diversification timeframes. However, given the uncertainty in mutation rates in Theraphosidae, diversification times should be interpreted with caution.
Mello, L. O., A. Morales, M. J., Arroyo-Pérez, W. Y., L. Guadanucci, J. P., Lima-Vergilio, R., & Solferini, V. N. (2026). Systematics and Historical Biogeography of Neotropical Tarantulas: A Genomic Approach to Dolichothele (Araneae: Theraphosidae) Diversification Across Domains. Journal of Biogeography, 53(10), e70384. https://doi.org/10.1111/jbi.70384
