Pablo Lehmann Albornoz

In a recent study based on the generalized mixed Yule coalescent method for delimiting species, a threshold of 2% genetic distance using cytochrome c oxidase subunit I sequences was used to delimit the species of Microglanis. That action resulted in assembling several populations of Microglanis from Atlantic coastal rivers between Rio Grande do Sul and São Paulo states as a single species, Microglanis cottoides, including Microglanis cibelae as a junior synonym. We reexamined these populations and found three species diagnosed by their morphology and that constitute separate mtDNA lineages, including a new species. The synonym of M. cibelae and M. cottoides is reviewed and refuted based on morphological and molecular evidence. M. cibelae and the new species are sympatric and occasionally syntopic in the Tramandaí, Mampituba, and Araranguá river basins. The new species is distinguished from M. cibelae and M. cottoides by the anterior margin of the posttemporosupracleitrum narrow articulated with the epioccipital, the short mental and maxillary barbels, and depressed head and body.

A new species of Ancistrus is described from the rio Vacacaí drainage, rio Jacuí basin, laguna dos Patos system, southern Brazil. The new species differs from A. brevipinnis, the common species in the laguna dos Patos system, by having a dark brown to black background body color and dorsal and caudal fins plain dark, without lighter spots or bands. A morphometric and molecular comparison of different populations of A. brevipinnis from the laguna dos Patos system suggests that previously undetected species diversity is present in that basin. The type-locality of A. brevipinnis, originally described as Rio Grande do Sul State, is herein restricted to the rio Camaquã sub-basin of the laguna dos Patos system, and a redescription of A. brevipinnis is provided based on that population.