Description of a new species of Ixodes Latreille, 1795 (Acari: Ixodidae) parasitizing small mammals in the Andean Chocó Biosphere Reserve of Ecuador

Ixodes is the most diverse genus of hard ticks worldwide, with nearly 62 species recorded in the Neotropical region, including nine in Ecuador. However, the diversity of this genus in the Ecuadorian Andean Chocó remains poorly understood. In this study, we describe a new species of Ixodes parasitizing small mammals from the Andean Chocó of Ecuador using an integrative taxonomic approach based on detailed morphological descriptions and molecular analyses. Ticks were collected from wild rodents and didelphids in the Mashpi Reserve, northwestern Pichincha Province, Ecuador, between March and August 2023. Specimens were identified and described using Neotropical taxonomic keys, light microscopy, and scanning electron microscopy (SEM). Partial mitochondrial 16S rRNA and cytochrome c oxidase subunit I ( COI ) gene sequences were generated and analyzed using maximum-likelihood phylogenetic inference. A total of 113 Ixodes specimens representing all parasitic stages were collected. Comparative morphological analyses demonstrated that these specimens represent a previously undescribed species. Ixodes mashpiensis n. sp. is described based on females, a male, nymphs, and larvae. Diagnostic morphological characters distinguish the new species from its closest congeners. Phylogenetic analyses of the 16S rRNA and COI genes recovered it as a strongly supported evolutionary lineage within the Neotropical Ixodes clade, providing independent support for its taxonomic recognition. Ixodes mashpiensis n. sp. increases the known diversity of Ixodes in Ecuador and represents the first species of the genus described from the Ecuadorian Andean Chocó. Its recognition is based on diagnostic morphological features and mitochondrial sequence divergence. These findings contribute to a better understanding of Neotropical tick diversity and provide a taxonomic framework for future studies on the ecology, evolution, host associations, and pathogen transmission of Neotropical Ixodes .