Testing adaptive radiation hypotheses in South American electric fishes: A phylogenomic approach

• Grant number: 19/25992-2
• Support type: Scholarships abroad - Research Internship - Post-doctor
• Effective date (Start): August 15, 2020
• Effective date (End): July 14, 2021
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Naercio Aquino Menezes
• Grantee: Luz Eneida Ochoa Orrego
• Supervisor abroad: Dahiana Katherine Arcila Mesa
• Home Institution: Museu de Zoologia (MZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: University of Oklahoma (OU), United States
• Associated to the scholarship: 18/23883-9 - Electric fishes of the genus Sternarchorhynchus, a case of adaptative irradiation in continental scale? A phylogenomic and morphological approach, BP.PD

Abstract

Understanding the drivers that promoted diversification and molded the history of the remarkable diversity of freshwater Neotropical fishes remain a central challenge in evolutionary studies. By integrating genomic and fossil data in a phylogenetic framework, the proposed project aims to address fundamental questions about the evolution of the South American Knifefishes (Gymnotiformes) such as when did the lineages originate? Have diversification rates through-time remained constant over time? How did speciation occur (e.g., via vicariance, dispersal, or via a combination of processes)? Gymnotiformes are excellent model organisms to study processes generating biological diversity due to their restricted distribution, unbalanced species richness, and morphological disparity. In contrast to their world-wide distributed sister-group (Siluriformes), Gymnotiformes are endemic to South America and comprise five families, 56 genera and over 260 extant species and a one fossil taxa (Humboldtichthys kirshbaumi; Upper Miocene, c. 10 Ma). The unevenly diversity distribution and phenotypic evolution within gymnotiforms represent a source of information to study macroevolutionary processes. For instance, morphological studies have suggested that an extreme modification in the anatomical complexes of the anterior portion of the head, which confer a unique mode of feeding suction aided by mechanical clamping or "grasp-suction" that can represent an evolutionary novelty, and this could be a factor for the triggering of adaptive radiation in some clades of the order. Considering the premise of pattern of adaptive radiation can be identified by comparative phylogenetic analysis, the present proposal aims to: 1) reconstruct the evolutionary history of gymnotiform fishes using two complementary methods of new generation sequencing: exon capture and restriction site associated DNA sequences (ddRADseq) and 2) testing the temporal and biogeographical scenarios of diversification in target groups with currently hypotheses of adaptive radiation in tropics.