Mepraia is a genus (Triatominae) endemic to Chile and a vector of Trypanosoma cruzi. Alternative phylogeographic hypotheses have been suggested for Mepraia. We tested different colonization routes hypothesized using mitochondrial sequences and phylogeographic approaches to select the best-supported hypothesis. Our results suggest that, after the split from the sister genus Triatoma at ~4.3 Mya, Mepraia formed two main clades at ~2.1 Mya. The northern clade diverged from Mepraia sp. ~1.7 Mya, giving rise to M. parapatrica and M. gajardoi about ~1.4 Mya. The southern clade originated M. spinolai ~1.68 Mya. We suggest that Mepraia had an origin in the north-central Andes along with orogenic processes, reinforced by hyperaridity during the Pliocene. The hyperarid cycle would have separated the southern and northern clades. Then, in the northern clade, dispersal occurred north and south from the centre through corridors during the Pleistocene Climatic Oscillations. Climate changes may have induced a major speciation process in the Atacama Desert, while the more homogeneous habitat colonized by the southern clade led to only one, but structured, species.

The Humboldt Archipelago, situated on Chile’s north-central coast, is renowned for its exceptional biodiversity. However, lizards of the Liolaemus genus are a particularly understudied group in this archipelago. Liolaemus genus is divided into two clades: chiliensis and nigromaculatus. Within the nigromaculatus clade the zapallarensis group is restricted to the semi-arid and arid coastal habitats of the Atacama Desert in north-central Chile. While it has been reported that lizards from the zapallarensis group inhabit various islands within the Humboldt Archipelago, there has been limited knowledge regarding their specific species identification. To identify the lizard species inhabiting these islands, we conducted phylogenetic analyses using a mitochondrial gene and examined morphological characteristics. Our findings reveal that lizards from the Damas, Choros, and Gaviota islands belong to Liolaemus silvai. In contrast, the lizards on Chañaral Island form a distinct and previously unrecognised group, clearly distinguishable from Liolaemus silvai. In conclusion, our study not only confirms the presence of L. silvai on the Damas, Choros, and Gaviota islands but also describes a new lizard species on Chañaral Island named Liolaemus carezzae sp. nov. These findings contribute valuable insights into the biodiversity of these islands and introduce a newly discovered endemic taxon to the region, enriching our understanding of Chile’s unique island ecosystems.

Trypanosoma cruzi, the protozoan causative of Chagas disease, is primarily transmitted through blood-sucking insects and infects mammalian and some reptilian hosts. In Chile, insects of the Mepraia genus are key vectors of T. cruzi in its wild transmission cycle. High prevalence and mixed infection of T. cruzi lineages have been reported in a Mepraia population on Santa María Island in the Atacama Desert. However, no small mammals have been reported. The island’s vertebrate community is dominated by the lizard Microlophus atacamensis and marine and scavenger birds. This study aimed to research blood samples of M. atacamensis for the presence of T. cruzi DNA (kDNA and satDNA) using conventional PCR (cPCR) and quantitative real-time PCR (qPCR) and estimate parasitemia. Our findings reveal that 39.4% of 33 individuals were positive with both cPCR and qPCR, while when assessing infection with either technique, it rises up to 81.8%. These findings confirm that M. atacamensis is a host of T. cruzi, suggesting its potential role as a key reservoir in the island’s transmission cycle. This study provides new insights into the life cycle of T. cruzi in the coastal Atacama Desert, highlighting the importance of reptiles in the epidemiology of this parasite.