Phylogenomics of trans-andean darters (Crenuchidae: Characidium) and investigation of biogeographic patterns and cryptic diversity

• Grant number: 24/16565-1
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Claudio de Oliveira
• Grantee: Leonardo Oliveira Silva
• Supervisor: Scott Schaefer
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Institution abroad: American Museum of Natural History, United States
• Associated to the scholarship: 23/09871-6 - Unraveling the diversity and origins of the genus Characidium (Characiformes: Crenuchidae) in the Neotropical region: a study of Systematics and Biogeography with a genomic and integrative approach, BP.PD

Abstract

The Neotropics, home to over 6,200 freshwater fish species, offer a rich tapestry of biodiversity, ideal for studying evolutionary mechanisms. Within this context, Characidium, a genus of freshwater fish endemic to the Neotropical region and the most representative of the family Crenuchidae, includes 85 species, of which 76 are found east of the Andes and nine west of the Andes. The species currently recognized in the trans-Andean region are C. boavistae, C. caucanum, C. chacoense, C. chupa, C. dule, C. marschi, C. phoxocephalum, C. sanctjohanni, and C. tatama. The monophyly of these species and their relationships with cis-Andean species remain unknown. Given the hypothesis that Characidium species originated in the Amazon River basin, the historical processes explaining their current occurrence in trans-Andean rivers are unclear. Additionally, records from scientific publications and collections suggest potential yet unknown diversity within trans-Andean Characidium populations, necessitating further investigation. We propose to combine the intellectual and genetic resources of researchers from Brazil, Colombia, Peru, USA, and Canada to reconstruct the evolutionary relationships of Characidium species in the trans-Andean region. Using a phylogenomic approach with Ultraconserved Elements (UCEs), via next-generation sequencing, we will test whether trans-Andean Characidium species form a monophyletic group, investigate their phylogenetic placement, and explore gene tree heterogeneity to support alternative relationships among these species. Additionally, we aim to investigate the presence of biogeographic patterns that could elucidate the observed phylogenetic relationships and distribution patterns, thereby exploring the key historical processes underlying the group's divergence between cis- and trans-Andean regions. We will also evaluate evidence of cryptic diversity within trans-Andean Characidium species. The present study will be fundamental for a better understanding of the evolutionary relationships within Characidium. Additionally, it has the potential to uncover previously undescribed species within the study area. (AU)