Genetic and morphological analysis of Herichthys pantostictus (Cichliformes: Cichlidae) populations that showed mitochondrial DNA introgression

Abstract

One factor that could explain the great diversity of cichlids is genetic introgression. In Mexico, there are 23 genera of cichlids; one of the most diverse is the genus Herichthys, which comprises 11 valid species. Herichthys pantostictus and H. carpintis are two species with a broad distribution in the Pánuco-Tamesí basin, where they often occur in sympatry. This study uses mitochondrial and nuclear sequences and morphological features to assess possible hybridization between these species. The phylogeny obtained with mitochondrial markers recovered the haplotypes of both species as paraphyletic, with a group of H. pantostictus haplotypes nested within the H. carpintis haplotypes. In contrast, the phylogeny obtained with the nuclear marker ITS-1 recovered the haplotypes of both species as reciprocally monophyletic. However, the traditional morphological features differed significantly between populations, but with a high degree of overlap, as did the geometric morphometrics, where there were no differences. In conclusion, we could detect signals of an ancient introgression, but did not observe morphological differences in the hybrid populations.

Keywords:
Cichlids; Geometric morphometrics; Hybrids; Phylogeny; Sympatry