Evidence on the paleodrainage connectivity during Pleistocene: Phylogeography of a hypoptopomatine endemic to southeastern Brazilian coastal drainages

Abstract

The coastal basins of southeastern Brazil are influenced by climatic changes that caused sea-level oscillations during the Pleistocene. These marine transgressions and regressions can generate isolation and connection among coastal rivers. In this region, freshwater fishes are excellent models for phylogeographic studies because their distributions may have been affected by geographical and ecological changes resulting from these processes. Therefore, the main objective of this study was to evaluate the effects of Pleistocene sea-level changes on the genetic structure of the loricariid Hisonotus leucofrenatus throughout its area of occurrence. Two genes were sequenced: Cytochrome Oxidase subunit 1 (mitochondrial gene) and rpS7 ribosomal protein gene intron 1 (nuclear gene) from specimens representing 14 river drainages. The genetic data corroborate a divide for freshwater fish by the Serra do Tabuleiro mountain in Santa Catarina State. This divide determines two main genetic groups in H. leucofrenatus: one group to the south and one to the north of this mountain range. The genetic structure observed coincide with the limits of estimated paleodrainage systems for the region, supporting that marine transgressions and regressions during the Pleistocene influenced the biogeographical history of H. leucofrenatus.

A taxonomically complex catfish group from an underrepresented geographic area: Systematics and species limits in Hypostomus Lacépède, 1803 (Siluriformes, Loricariidae) from Eastern South America

“…The distribution of species in neighboring basins suggests a possible connectivity of rivers that eventually allowed their dispersal. In fact, these connections have already been tested for freshwater fish within the NMA and they are usually explained by coastal paleodrainages (Pio & Carvalho, 2021; Thomaz & Knowles, 2018; Weitzman et al, 1988) or river capture events (Argolo et al, 2020; Barreto et al, 2020; Bishop, 1995). In addition, the preference for habitats such as small rivers with running waters and the strong niche conservatism in the early evolution of Hypostomus suggest that most dispersal events were driven by river captures (Bagley et al, 2021; Jardim de Queiroz et al, 2021).…”