Phylogeography of Baryancistrus xanthellus (Siluriformes: Loricariidae), a rheophilic catfish endemic to the Xingu River basin in eastern Amazonia

• Published in: PloS one 2021-08, Vol.16 (8), p.e0256677-e0256677
• Main Authors: Magalhães, Keila Xavier, Silva, Raimundo Darley Figueiredo da, Sawakuchi, André Oliveira, Gonçalves, Alany Pedrosa, Gomes, Grazielle Fernanda Evangelista, Muriel-Cunha, Janice, Sabaj, Mark H, Sousa, Leandro Melo de
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Baryancistrus xanthellus; Bayesian analysis; Bedrock; Biological diversity; Biology and Life Sciences; Brazil; Catfish; Catfishes - genetics; Conservation; Dams; Demographics; Demography; Earth Sciences; Ecology and Environmental Sciences; Endemic animals; Endemic species; Floods; Gene flow; Gene Flow - genetics; Genes, Mitochondrial - genetics; Genetic diversity; Genetic structure; Genetic Variation - genetics; Geographical distribution; Haplotypes; Historical structures; Hydroelectric dams; Introns; Life history; Loricariidae; Mitochondria; Phylogeography; Population genetics; Population structure; Populations; Prolactin; Rainfall; Rapids; Ribosomal protein L3; Ribosomal Protein L3 - genetics; River basins; River channels; River mouth; Rivers; Statistical inference; Substrates; Tributaries; Water discharge
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0256677

Baryancistrus xanthellus (Loricariidae) is an endemic fish species from the Xingu River basin with its life history in the shallow rapid waters flowing over bedrock substrates. In order to investigate the genetic diversity and demographic history of B. xanthellus we analyzed sequence data for one mitochondrial gene (Cyt b) and introns 1 and 5 of nuclear genes Prolactin (Prl) and Ribosomal Protein L3 (RPL3). The analyses contain 358 specimens of B. xanthellus from 39 localities distributed throughout its range. The number of genetically diverged groups was estimated using Bayesian inference on Cyt b haplotypes. Haplotype networks, AMOVA and pairwise fixation index was used to evaluate population structure and gene flow. Historical demography was inferred through neutrality tests and the Extended Bayesian Skyline Plot (EBSP) method. Five longitudinally distributed Cyt b haplogroups for B. xanthellus were identified in the Xingu River and its major tributaries, the Bacajá and Iriri. The demographic analysis suggests that rapids habitats have expanded in the Iriri and Lower Xingu rivers since 200 ka (thousand years) ago. This expansion is possibly related to an increase in water discharge as a consequence of higher rainfall across eastern Amazonia. Conversely, this climate shift also would have promoted zones of sediment trapping and reduction of rocky habitats in the Xingu River channel upstream of the Iriri River mouth. Populations of B. xanthellus showed strong genetic structure along the free-flowing river channels of the Xingu and its major tributaries, the Bacajá and Iriri. The recent impoundment of the Middle Xingu channel for the Belo Monte hydroelectric dam may isolate populations at the downstream limit of the species distribution. Therefore, future conservation plans must consider the genetic diversity of B. xanthellus throughout its range.