Lima, Sérgio Maia QueirozCosta, Silvia Yasmin Lustosa2021-03-232021-03-232020-05-20COSTA, Silvia Yasmin Lustosa. Taxonomia integrativa e biogeografia dos cascudos do gênero Hypostomus Lacépède,1803 (Siluriformes: Loricariidae) nas drenagens do Nordeste brasileiro. 2020. 180f. Tese (Doutorado em Sistemática e Evolução) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2020.https://repositorio.ufrn.br/handle/123456789/31983Northeast Brazil comprises four biomes (Caatinga, Cerrado, Atlantic Forest and the Amazon) and five continental hydrographic ecoregions: Northeast Caatinga and Coastal Drainages (CNDC), Parnaíba (PNB), São Francisco (SAFR), Northeast Atlantic Forest (MANE), and the Amazon Basin and Coastal Drainage Estuary (EADC). In the last decades, several species of fish have been described from these ecoregions, including some of the armored catfish of the genus Hypostomus, the richest of the Loricariidae family and one of the most widely distributed in the entire Neotropical region. In two of the five ecoregions mentioned above (CNDC and PNB), nine nominal species of Hypostomus are known, seven for CNDC and two for PNB. However, many of these species described until the mid-twentieth century, have some problems, such as the lack of definition of the type localities, few specimens that make up the type series and are diagnosed based on few external morphological characters. Intraspecific variability acts as a complicating factor in the definition of species of the genus in the aforementioned ecoregions, which causes problems when assessing their conservation status. The aim of the present study was to carry out a taxonomic review of the species of Hypostomus in the CNDC and PNB ecoregions, using integrative taxonomy, and to discuss the diversification of the genus in the drainages of the semiarid of the Northeast. Based on our results, Hypostomus carvalhoi, H. jaguribensis, H. nudiventris, H. papariae and H. salgadae are junior synonyms of H. pusarum. The geographical distribution of H. pusarum was expanded to the PNB and two new species of the genus, described here, were revealed for this ecoregion. We provided data on the distribution of the species of the genus in the studied ecoregions, and recorded the occurrence of six species of Hypostomus (H. johnii, H. Pusarum, H. vaillanti and two described in this study and another possible new species) in the ecoregion PNB. The results indicate that the species richness of the genus at CNDC is overestimated, while in the PNB it is still underestimated. Phylogenetic relationships were observed between a group of species from CNDC and PNB with species from the Amazon region and the Guianas, as well as past relationships between these ecoregions with the SAFR, and the latter with the tributaries of the La Plata system. In addition, we conclude that the color pattern of the species evolved independently in most formed clades. Our biogeographic inferences suggest that there were at least two Hypostomus diversification events at CNDC and PNB, and at least three at SAFR, and most of the processes that acted on these events in the Northeast semiarid region were headland catches. According to our results, the species diversified between the late Miocene and the Pliocene, which coincides with the period of lower temperatures on the globe, a condition that possibly led to the expansion of the semiarid areas of the region.Acesso AbertoCaatingaCaptura de cabeceirasDNA BarcodeHypostominaeRio ParnaíbadoctoralThesis