The genus Ixodes is the most species-rich group of hard ticks on the planet, and the Neotropical region alone harbors nearly 62 recognized species. Ecuador has so far recorded nine of them, yet the authors of the new study emphasize that the true diversity of these parasites in the country’s northwestern montane forests remains poorly understood. Ticks of this genus matter far beyond their taxonomic interest: several Ixodes species are notorious vectors of disease-causing agents, including the bacteria responsible for Lyme borreliosis in other parts of the world. Knowing exactly which tick species live where, and which animals they feed on, is therefore a foundation for understanding disease ecology in tropical ecosystems.

The fieldwork behind the discovery took place in the Mashpi Reserve, a protected cloud forest site within the wider biosphere reserve. Researchers captured wild rodents and didelphids, the marsupial family that includes opossums, and carefully collected the ticks parasitizing them. In total, 113 Ixodes specimens were gathered, representing every parasitic life stage of the tick: larvae, nymphs, females, and even a single male. Recovering all of these stages from the same host community is a significant advantage in tick taxonomy, because the morphology of each stage can differ dramatically, and describing a species from only one life stage leaves room for ambiguity.

To determine whether the specimens truly represented something new, the team applied an integrative taxonomic approach, combining classical morphology with molecular genetics. Under light microscopy and, in greater detail, scanning electron microscopy, the researchers examined the fine anatomical structures that taxonomists use to separate closely related tick species. These include features of the mouthparts, the dorsal shield known as the scutum, the arrangement of grooves and punctations on the body surface, and the shape of structures such as the spiracular plates and anal groove, which in Ixodes characteristically curves around the anus in front of it. The specimens were first run through existing Neotropical taxonomic keys, and comparative analysis showed that they did not match any of the described species.

The molecular side of the study focused on two mitochondrial genes that have become standard tools in tick barcoding and phylogenetics: the 16S ribosomal RNA gene and cytochrome c oxidase subunit I, commonly abbreviated COI. The team generated partial sequences of both genes from the specimens and analyzed them using maximum-likelihood phylogenetic inference, a statistical method for reconstructing evolutionary relationships from DNA data. Sequences were aligned and compared against public databases using the BLASTn search tool, and the resulting phylogenetic trees placed the new ticks as a strongly supported evolutionary lineage within the Neotropical Ixodes clade. In other words, the DNA evidence independently confirmed what the morphology suggested: this was a species that science had not yet named.

With both lines of evidence in agreement, the researchers formally described Ixodes mashpiensis based on the females, the male, the nymphs, and the larvae, designating type specimens that anchor the name for future study. Diagnostic morphological characters distinguish the new species from its closest congeners, the related species against which it was compared. The species epithet mashpiensis honors the Mashpi Reserve, the cloud forest site where the ticks were collected, and where the research was supported by the Department of Research and Biology of Mashpi Lodge, an ecotourism operation that has invested in on-site scientific research.

The significance of the finding extends past the addition of one name to the tick catalogue. Ecuador’s Andean Chocó sits at the intersection of the Andes and the Chocó biogeographic region, a corridor of extremely high endemism where new species of plants, amphibians, birds, and mammals continue to be described. Parasites, however, are frequently overlooked in biodiversity inventories, even though they can be just as specialized and just as vulnerable to extinction as their hosts. Each undocumented parasite species represents an unknown quantity in disease ecology: without knowing which ticks occur in an area and which hosts they feed on, researchers cannot assess which pathogens might circulate there or how transmission networks are structured.

The authors note that the recognition of Ixodes mashpiensis provides a taxonomic framework for future studies on the ecology, evolution, host associations, and pathogen transmission of Neotropical Ixodes. Because the new species was found parasitizing wild rodents and opossums, both groups known to serve as reservoirs for a range of zoonotic organisms, follow-up work could examine whether this tick feeds on humans or domestic animals, and whether it carries any disease agents. The study itself did not report pathogen screening, so questions about the medical or veterinary importance of Ixodes mashpiensis remain open. What the study does establish is the essential first step: a reliable, diagnosable species identity backed by both anatomy and DNA.

The research was carried out by a team spanning Ecuador, Brazil, Uruguay, and Mexico, led by first author Vanessa H. Mosquera of the Universidade Federal de Viçosa in Brazil and the Universidad Central del Ecuador in Quito, with corresponding author Sandra Enríquez coordinating the work from the Instituto de Investigación en Zoonosis in Quito. The project received financial support from the Brazilian National Council for Scientific and Technological Development and the Coordination for the Improvement of Higher Education Personnel, alongside institutional backing from the Universidad Central del Ecuador and Mashpi Lodge. All animal and tick collections were authorized by Ecuador’s Ministry of Environment, Water and Ecological Transition and approved by the university’s animal research ethics committee, reflecting the regulatory safeguards required for biodiversity research in the country.

For now, Ixodes mashpiensis stands as a reminder of how much undiscovered life persists in the world’s cloud forests, including organisms small enough to escape notice until someone looks closely. The known tick fauna of Ecuador has grown by one species, and the Andean Chocó has gained its first formally described Ixodes. As molecular tools become cheaper and field surveys reach deeper into remote reserves, researchers expect that more such lineages will come to light, each one sharpening the picture of how parasites, hosts, and pathogens are woven together in one of the most biodiverse landscapes on Earth.

Subject of Research: Integrative taxonomic description of a new Ixodes tick species parasitizing small mammals in the Ecuadorian Andean Chocó

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

Article References: Mosquera, V. H., Venzal, J. M., Martins, G. F., Guevara-Camacho, J. M., Brito, J., Pozo, S., Aguilar-Guerrero, A., Roldán, M., & Enríquez, S. (2026). Description of a new species of Ixodes Latreille, 1795 (Acari: Ixodidae) parasitizing small mammals in the Andean Chocó Biosphere Reserve of Ecuador. Parasites & Vectors. https://doi.org/10.1186/s13071-026-07645-1

Image Credits: AI Generated

DOI: 10.1186/s13071-026-07645-1

Keywords: Ixodes, ticks, Ecuador, Andean Chocó, taxonomy, new species, small mammals, 16S rRNA, COI, phylogenetics, Parasites & Vectors, biodiversity

The scale of the underlying field effort is remarkable. Between 2013 and 2025, members of the Hokkaido University Tick Hunting Team, joined by collaborators across the country, systematically dragged cloth flags through vegetation at 1,018 sites spanning 38 of Japan’s 47 prefectures. This flagging method, the standard technique for sampling host-seeking ticks, involves pulling a white cloth square across low vegetation so that questing ticks latch onto it. The surveys yielded a total of 22,416 individual ticks, representing the sixteen species that formed the basis of the modeling work. Because tick distribution data have historically been restricted to localized studies, this dataset provides an unusually broad and consistent foundation for predicting where each species can persist across the entire Japanese archipelago.

To transform field observations into predictive maps, the team employed the maximum entropy method, widely known as Maxent, a machine-learning approach that estimates the probability of species presence from occurrence records and environmental variables. The models incorporated three categories of predictors: climatic variables such as temperature and precipitation, topographic features such as elevation, and landscape variables describing land cover and habitat type. The resulting predictions were generated at a resolution of one square kilometer, fine enough to distinguish habitat suitability between neighboring valleys or forest patches. Model performance was robust across the sixteen species, giving the researchers confidence that the maps capture genuine ecological patterns rather than statistical noise.

Among all the environmental variables tested, one emerged with unexpected prominence: snow depth. For six of the sixteen tick species, snow depth contributed the largest share of explanatory power in the models. This finding carries real ecological weight. Deep, persistent snow insulates the ground layer where ticks overwinter, moderating the extreme cold that would otherwise kill them, but it also shapes the length of the active season and the structure of the vegetation communities ticks depend on. In a country that stretches from subtropical Okinawa to the frigid northern island of Hokkaido, snow depth turns out to be a fundamental determinant of where ticks can establish populations, and by extension, where the pathogens they carry can circulate.

The predicted suitable habitats showed striking interspecific variation, following both latitudinal and elevational gradients. Some species are confined to the cool, snowy north, while others thrive in the warmer south; some occupy lowland forests, others climb into mountain terrain. This diversity of distribution patterns matters because each tick species is a competent vector for a different set of pathogens. A map that lumps all ticks together would obscure precisely the spatial structure that determines which diseases threaten which communities. The new species-by-species approach reveals that patchwork in detail for the first time.

The most consequential step of the analysis went beyond mapping habitats and asked whether the predicted distributions actually explain where human cases of tick-borne disease occur. The researchers converted their one-kilometer probability maps into prefecture-level statistics, calculating for each of Japan’s prefectures the proportion of grid cells predicted to be occupied by each tick species. They then used regression analyses to test whether these occupancy proportions could account for the reported numbers of five notifiable tick-borne diseases: severe fever with thrombocytopenia syndrome, tick-borne encephalitis, Japanese spotted fever, Lyme disease, and relapsing fever. The answer was a clear yes, with significant correlations between the predicted area occupied by suspected vector species and the reported case counts for each disease.

The species-disease alignments were biologically coherent in ways that strengthen confidence in the results. For diseases with a predominantly northern distribution, such as Lyme disease, the predicted distributions of Ixodes pavlovskyi and Ixodes persulcatus aligned closely with reported case occurrence, and both species are known vectors of the Borrelia bacteria that cause the illness. At the opposite end of the map, Haemaphysalis flava emerged as the primary contributor to model performance for Japanese spotted fever and the secondary contributor for severe fever with thrombocytopenia syndrome, two diseases concentrated in southern and western Japan. Again, the correlated species are recognized vectors of the corresponding pathogens. In other words, the models did not merely find statistical associations; they recovered the known vector ecology of each disease from environmental data alone.

This external validation against disease surveillance data is what elevates the study from a biogeographic exercise to a practical public health tool. Species distribution models are often evaluated solely on their ability to reproduce the occurrence records used to build them, which risks circularity. By demonstrating that independently collected human disease reports track the predicted tick distributions, the researchers provided evidence that the maps capture something real about transmission risk on the ground. For public health authorities, this means the maps can serve as an early-warning layer, highlighting prefectures where environmental conditions favor vector species even before cases accumulate.

The implications extend beyond Japan’s borders. Climate change is expected to shift temperature and snowfall patterns across temperate Asia, and because snow depth proved to be such a powerful predictor, changes in snow cover could redraw the boundaries of tick habitat in the coming decades. Species currently confined to Hokkaido’s snowy forests might expand southward or upslope, carrying tick-borne encephalitis and other northern diseases into new territories. Conversely, warming could compress the suitable habitat of cold-adapted species. The modeling framework established in this study, with its one-kilometer resolution and multi-species coverage, provides a baseline against which such shifts can be measured and anticipated.

The study also demonstrates the value of sustained, collaborative fieldwork. Twelve years of surveys, involving dozens of students and researchers in the Hokkaido University Tick Hunting Team and partner laboratories from Kitasato University, the University of Tokyo, the University of Osaka, and beyond, produced the occurrence data that no amount of modeling ingenuity could substitute for. The authors note that the resulting maps, offering a nationwide overview of tick distributions, serve as basic information for anticipating the occurrence of tick-borne diseases in the region. For clinicians, the maps offer context for differential diagnosis when patients present with fever after outdoor exposure; for epidemiologists, they provide a spatial framework for surveillance prioritization; and for the public, they offer a clearer picture of the invisible landscape of risk that accompanies a walk through Japan’s forests and grasslands.

Subject of Research: Species distribution modeling of tick vectors and tick-borne disease occurrence in Japan

Article Title: Predicting the distribution of 16 tick species in Japan and its association with the occurrence of tick-borne diseases

Article References: Ito, M., Ohari, Y., Ohsugi, Y., Taya, Y., Hayashi, N., Ogata, S., Kusakisako, K., Qiu, Y., Nonaka, N., Mizuma, K., Torii, S., Kajihara, M., Hokkaido University Tick Hunting Team (HUT-HuT), Mimura, Y., Regilme, M. A. F., Thu, M. J., Kovba, A., Kwak, M., Teo, E., … Nakao, R. (2026). Predicting the distribution of 16 tick species in Japan and its association with the occurrence of tick-borne diseases. Parasites & Vectors. https://doi.org/10.1186/s13071-026-07717-2

Image Credits: AI Generated

DOI: 10.1186/s13071-026-07717-2

Keywords: ticks, species distribution modeling, Maxent, Japan, Lyme disease, severe fever with thrombocytopenia syndrome, Japanese spotted fever, tick-borne encephalitis, snow depth, vector ecology, public health, Ixodes