The role of the \"Cordillera Blanca\" (Ancash, Peru) in the evolutionary history of sigmodontinae rodents in northern Peru

• Ano de defesa: 2023
• Autor(a) principal: Rengífo Vasquez, Edgardo Manuel
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Andes; Endemism; Endemismo; Genômica; Genomics; Morfologia; Morphology; Sigmodontinae
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/91/91131/tde-10072023-163409/

The Andes are the most important mountain chain in South America, possessing a remarkable species richness, including many endemic taxa. Furthermore, the Andes represent an interesting area to develop evolutionary and biogeographical studies. Here, my main objective was to investigate how the uplift of the Cordillera Blanca has influenced the evolutionary history of sigmodontinae rodents on the highland of the Ancash department in Northern Peru. Firstly, I introduced the Andes showing the community assembly of small no-volant mammals, and identified the endemism pattern of sigmodontinae rodents in the Andean region. Afterward, I divided my thesis into three chapters. Chapter 1 is a general introduction in which I briefly present the Andes, succinctly mentioning the evolutionary processes that have led to harboring the current diversity; additionally, I also present each chapter\'s justification and hypotheses. Chapter 2 aims to raise an overview of the Andes, with an update on the status of the biogeographic knowledge for small non-volant mammals and identify areas of endemism of the rodents of the subfamily Sigmodontinae in the Andes. To accomplish this goal, i) I compiled information from non-volant small mammals community assembly in high Andean regions and ii) to identify the areas of endemism of the sigmodontinae I employed an analysis of endemicity using the NDM/VNDM software. As a result, I obtained information from 630 mammalian communities from seven South American countries and compiled 26,534 records of individuals belonging to 241 species. The Order with the highest number of records was Rodentia. The species accumulation curve suggests that the dataset covers an adequate representation. The Analysis of endemicity recovered eight areas of endemism (AoE); broadly, the patterns of AoE found here are congruent with those previously delimited using other methods and in other taxa. Chapter 3 aims to evaluate the intra and inter-populational morphologic and genetic variation of the rodents distributed on both sides of the Cordillera Blanca, I applied classical morphological methods and ddRADseq technique in the eight most abundant sigmodontinae species that occur in the highlands of Ancash department in Peru (Akodon mollis, Microryzomys altissimus, Oligoryzomys andinus, Calomys sorellus, Auliscomys pictus, Phyllotis andium, P. occidens, and Thomasomys praetor). The results showed a common pattern of close relationships between populations on the eastern and western slopes of Cordillera Blanca, suggesting that Cordillera Blanca would not represent an effective geographic barrier. Conversely, my data show that gene flow rates across the Santa River drainage are relatively low or null, greater at headwaters. In this sense, I reject the hypothesis that the Cordillera Blanca has driven the allopatric speciation of sigmodontinae. Lastly, Chapter 4 presents a synthesis of the main conclusions and future perspectives on the study of sigmodontinae in the Andes.