Phylogenomics of Myleinae (Characiformes: Serrasalmidae) based on ultraconserved elements (UCEs): exploring evolutionary relationships and diversity

• Grant number: 24/22720-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2025
• End date: July 31, 2028
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Claudio de Oliveira
• Grantee: Victória Dandara Pereira e Silva
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated research grant: 20/13433-6 - Phylogeny and molecular identification of fishes of the superorder Ostariophysi (Chordata: Actinopterygii) using genomic approaches, AP.TEM

Abstract

Within Serrasalmidae, Myleinae stands out as the most diverse subfamily, encompassing nine genera of species popularly known as "pacus". Furthermore, Myleinae presents a large number of species, with 12 new species described in the last ten years alone. Currently, the subfamily comprises 41 valid species widely distributed in the Cis-Andean region. Although there have been advancements in species descriptions over the last decade, the relationships among the genera within the subfamily remain unresolved. Recent phylogenetic analyses suggest the non-monophyly of at least five out of the nine genera of Myleinae. Unexpected relationships, such as the genetic proximity between Ossubtus xinguense and Myloplus sauron, two species that are extremely distinct morphologically, have been recovered in molecular analyses involving different markers. As molecular analyses have become more widely used, the morphological characters related to dentition, previously employed to separate groups, have been revealed as evolutionary convergences or parallelisms rather than sinapomorfies of Myleinae genera. In the most comprehensive of the recent phylogenetic hypotheses, based on Ultraconserved Elements (UCEs), only 22 of the 41 species comprising Myleinae were sampled. Given the still unresolved phylogenetic relationships among the family's genera, we propose the development of an updated UCEs based phylogeny, including all species of the subfamily. In parallel, an integrative taxonomic study will be conducted to generate a more robust delimitation of the currently known species of the group, as well as to identify and describe potential new species.