Banca de DEFESA: RAFAEL BURGER

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RAFAEL BURGER
DATA : 30/08/2019
HORA: 09:00
LOCAL: Instituto de Biologia (Sala 01) - Universidade Federal da Bahia
TÍTULO:

Taxonomy and evolutionary history of the genus Astyanax Baird & Girard in Paraguaçu river basin: description of new species and delimitation of lineages based on an integrative approach

PALAVRAS-CHAVES:

Paraguaçu, Integrative taxonomy, Bahia, local morphotypes, identification key

PÁGINAS: 220
GRANDE ÁREA: Ciências Biológicas
ÁREA: Zoologia
RESUMO:

Correct species delimitation is fundamental to biodiversity knowledge. The genus Astyanax has a complex taxonomy and most of its species don’t have a good taxonomic or geographical delimitation and are often identified only to genus level. Moreover, currently the genus is not considered as a monophyletic group. According to the literature, more than 10 species of Astyanax are known to the rio Paraguaçu basin, Bahia, Brazil, being a surprisingly high number, considering the size of this basin. However, these species were identified only at genus level. This PhD thesis deals with that issue and is divided into three chapters. In chapters one and two, respectively two and one new species of Astyanax are described, with sufficient morphological characteristics for their diagnosis from all congeners, increasing the number of described species of Astyanax to six in the rio Paraguaçu, all endemic to the basin and with restricted distribution to the Chapada Diamantina region. In the third chapter, a study was carried out with an integrative approach (morphological and molecular data), aiming to delimit the independent evolutionary lineages of the genus Astyanax in the rio Paraguaçu basin. In this chapter, besides listing the lineages and their distributions, we investigate the processes that led to the diversification of the group and the possible causes of incongruences found between the results obtained from the different data. An integrative approach, with morphological and molecular data, was carried to delimit the Astyanax lineages of the rio Paraguaçu basin, discuss their relationships and discuss their distribution patterns. Molecular analyzes were based on COI, a mitochondrial molecular marker, and four species delimitation methods were implemented. All six species of Astyanax previously known for the Paraguaçu basin were recovered and 12 additional lineages of the genus were evidenced. Strong genetic structure was found, allowing the recognition of two very divergent main clades, composed of genetically structured lineages. Incongruences between molecular and morphological data suggest the occurrence of different processes, including recent speciation events, incomplete lineage sorting, possible mitochondrial DNA introgression and recurrence of morphological convergences. The intricate hydrographic network of the upper rio Paraguaçu, in the Chapada Diamantina region, associated with river capture events should be strongly related to the high number of lineages and distribution of Astyanax species in the rio Paraguaçu basin. Sixteen of the 18 lineages are considered endemic, reinforcing the high endemism of the ichthyofauna in this basin.

MEMBROS DA BANCA:
Presidente - 1561582 - ANGELA MARIA ZANATA
Interno - 032.280.047-16 - PAULO ROBERTO ANTUNES DE MELLO AFFONSO - UFSCAR
Interno - 1299193 - ALESSANDRA SELBACH SCHNADELBACH
Externo à Instituição - VITOR PIMENTA ABRAHÃO
Externo à Instituição - LUIZ FERNANDO DUBOC DA SILVA