Banca de DEFESA: LEONARDO OLIVEIRA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LEONARDO OLIVEIRA SILVA
DATE: 04/03/2022
TIME: 13:00
LOCAL: ambiente virtual
TITLE:

Systematic and biogeography of Characidium (Crenuchidae): a integrative study in four neotropical ecoregions

KEY WORDS:

Characidiinae, coastal basins, diversification, Neotropical Region, Phylogeography, Taxonomy

PAGES: 238
BIG AREA: Ciências Biológicas
AREA: Zoologia
SUBÁREA: Taxonomia dos Grupos Recentes
SUMMARY:

Characidium includes 83 valid species and is considered a monophyletic genus widely distributed in rivers in South America. Variations in color pattern and external morphology, as well as the fact that many populations in the literature have been identified only at the genus level, suggest that some of the Characidium species actually represent species complexes. This thesis addresses delimitation issues involving Characidium species in freshwater ecoregions with rivers that drain in northeastern Brazil, an area that remains poorly studied when it comes to the genus. Chapters one, two, and three deal with the description of three new species of the genus, expanding the number of species found in rivers draining the ecoregions of interest. In chapter four, a taxonomic study using an integrative approach with morphological and molecular data was conducted, aiming to delimitate the species of the genus Characidium in the rivers of these ecoregions and to discuss the relationships between them and between them and other congeners, as well as their distribution pattern. For this purpose, in addition to the morphological approach, a molecular phylogenetic analysis and three molecular delimitation analyzes of species based on the mitochondrial marker cytochrome oxidase I were performed. Thus, 15 Operational Evolutionary Units (OTUs) were delimited as species hypotheses supported by morphological data and by the results of at least one method of molecular delimitation: 10 correspond to valid species already known for the studied areas, four are morphotypes similar to already described species but with features that do not allow their identification as such, and one UTO corresponds to a potential new species yet to be described. Furthermore, incongruities between the results of morphological and molecular data were found in the delimitation of C. bahiense, C. bimaculatum, C. gomesi, and some proposed morphotypes. The results also suggest that Characidium species from ecoregions that include rivers draining northeastern Brazil do not form a monophyletic group, since some species studied are more closely related to species from other ecoregions. Finally, in chapter 5, the intraspecific limits involving disjunct populations of C. bahiense and the history of diversification of these populations were investigated through a multilocus molecular approach and morphological data. Also in this chapter, reconstruction data from coastal paleodrainages during the Last Glacial Maximum, and possible river captures, were used to investigate the distribution of genetic variation found for this species. The results show the occurrence of mitonuclear discordance, in which two proposed lineages based on mtDNA appear as structured and non-monophyletic. Multilocus analyses, including nuclear markers, however, recover the monophyly of these lineages and show a recent diversification among the populations of the species. Morphological data indicate that all specimens of C. bahiense analyzed are conspecific. Nonetheless, the results suggest that the current distribution of C. bahiense may have been directly influenced by changes in the course of the São Francisco River and by geomorphological events of river captures between the basins where the species occurred during the Pleistocene. All the results obtained herein are part of a pioneering study carried out with the family Crenuchidae, where most of the work has focused on species from the Amazon.

BANKING MEMBERS:
Presidente - 1561582 - ANGELA MARIA ZANATA
Interno - 032.280.047-16 - PAULO ROBERTO ANTUNES DE MELLO AFFONSO - UFSCAR
Interna - 1299193 - ALESSANDRA SELBACH SCHNADELBACH
Externo à Instituição - HENRIQUE ROSA VARELLA
Externa à Instituição - MANOELA MARIA FERREIRA MARINHO
Externa à Instituição - FLÁVIA DE FIGUEIREDO PETEAN
Externa à Instituição - SILVIA BRITTO BARRETO
Externa à Instituição - LUZ ENEIDA OCHOA ORREGO
Externo à Instituição - MURILO NOGUEIRA DE LIMA PASTANA