Mammals as engines of diversification: revisiting the evolutionary history of the Trypanosoma cruzi clade

Abstract

The Trypanosoma cruzi clade represents one of the most complex and ecologically diverse assemblages of mammalian trypanosomes. Although the group’s human pathogenic member T. cruzi is best known as the etiological agent of Chagas disease, its evolutionary origins remain debated. Two main hypotheses attempt to explain the diversification of the T. cruzi clade: the supercontinent hypothesis, which proposes an ancient co-diversification with South American marsupials, and the bat-seeding hypothesis, which suggests a more recent origin through host-switching from bat trypanosomes. Here, we combined parasite and host phylogenies with global-fit cophylogenetic analyses to evaluate whether mammalian diversification has influenced the evolutionary history of the T. cruzi clade. Using PACo and ParaFit, we detected a weak but statistically significant global correspondence between mammal and trypanosome phylogenies. This correspondence was primarily associated with bat-trypanosome relationships, whereas associations involving non-bat mammals showed limited phylogenetic concordance. Together, these findings suggest that mammalian diversification may have influenced trypanosome evolution across multiple evolutionary contexts and timescales.