https://onlinelibrary.wiley.com/doi/abs ... /jfb.14538
Epactionotus advenus new species
Species of Epactionotus are known for inhabiting the rocky‐bottom stretches of fast‐flowing rivers in a limited geographic area along the Atlantic coast of southern Brazil. These species are endemic to single coastal river drainages (two neighboring drainages for E. bilineatus) isolated from each other by the coastal lacustrine environments or the Atlantic Ocean. Epactionotus bilineatus is from the Maquiné and Três Forquilhas river basins, both tributaries of the Tramandaí River system, while E. itaimbezinho is endemic to the Mampituba River drainage, and E. gracilis to the Araranguá River drainage. Recent fieldwork in the Atlantic coastal drainages of southern Brazil revealed new populations in the Urussanga, Tubarão, d’Una, and Biguaçu river drainages. Iterative species delimitation using molecular data (cytochrome oxidase subunit I ‐ COI) and morphology (morphometrics and meristics) were applied to evaluate species recognition of isolated populations. In light of new data, the genus was re‐diagnosed; the status of Epactionotus species/populations was reevaluated, formerly described species were supported, and population structure was recognized. As for the newly discovered populations, both morphological and molecular data strongly support the population from the Biguaçu River drainage, in Santa Catarina State, as a new species. Molecular data revealed strong per basin population structure, which may be related to species habitat specificity and low or no dispersal among drainages.