Macroevolution of Pike Cichlids (Teleostei: Cichlidae: Crenicichla and Teleocichla) in South America: total evidence analyses using an exon-based phylogenomic approach

Abstract

The fishes of the genera Crenicichla (92 valid species) and Teleocichla (9 rheophilic Amazonian species) constitute a clade strongly corroborated by morphological and molecular phylogenies. In the last ten years, a lot of attempts have been made to increase the knowledge about taxonomy and phylogenetic relationships between the species of this diverse group. These include two recent phylogenies using a phylogenomic approach based on Ultraconserved elements (UCEs; 2017) and on dd RADseq (2018), which attempted to clarified the interrelationships and proposed some hypotheses about the evolution of the species groups. Althouth there is concordance on the division of Crenicichla in species groups, those analyses do not encompassed the entire diversity of the clade and the evolutive inferences might be restricted to species groups occurring only in the South of Brasil, Argentina and Uruguay. During the doctoral project, the candidate performed the most comprehensive analysis of the clade Crenicichla-Teleocichla, using morphological characters. In this study, a new classification has been proposed according to monophyletic groups with synapomorphies, but, more importantly, a great amount of information on the morphology of all species of Crenicichla and Teleocichla was codified and is now available. Concomitantly, a powerful and acessible technology for phylogenomic analysis using Next Generation Sequencing (NGS) based on exon-captur has been recently developed for cichlids. In other words, as this moment, we have an extraordinary opportunity to study macroevolution of these pike cichlids on a continal scale by means of total evidence analyses with a phylogenomic approach. Thus, we proposed the following objectives for this pos-doctoral project: 1) to develop a phylogenomic analysis of Crenicichla and Teleocichla using NGS based on exon-capture; 2) using a relaxed molecular clock approach, to offer temporal structure to the phylogeny proposed and to estimate times of lineage diversification; 4) to develop analyses of morphological disparity through time based on the morphological characters already surveyed by the applicant. The application of NGS methods have resulted in phylogenies far more robust than those generated with traditional molecular multilocus analyses. Competing hypotheses on evolutionary patterns and processes can be tested by model comparison on time-calibrated phylogenies: if the phylogeny is more robust and well-resolved, so the inferences about these issues may be considered more plausible. This project counts with the participation of the Hernán López-Fernández´s (Universidade de Michigan), where the exon-capture probes have been designed (also counting on funding for sequencing). This project also represents a partnership between the major international leaders of Cichlidae research (H. López-Fernández and Sven Kullander) with this Brazilian lab, and this might result in a long and very productive line of research in Brazil. (AU)