The tropical horse tick, Dermacentor nitens Neumann, 1897, has a wide distribution throughout the Neotropics, and is a vector of protozoan haemoparasites that cause equine piroplasmosis. Despite this, little is known about the genetic diversity of this tick species, particularly in Cuba, where horses are important domestic animals used in agriculture and for transportation. The objective of this study was to assess the magnitude of genetic variation in 115 D. nitens adults (57 females and 58 males) collected from horses in the Cuban province of Mayabeque using sequence data of two mitochondrial genes, cytochrome c oxidase subunit 1 gene (cox1) and NADH dehydrogenase subunit 4 gene (nad4). The results revealed the presence of 7 cox1 haplotypes, 14 nad4 haplotypes, and 23 haplotypes with concatenation of the two genetic markers. However, the results of the rarefaction curve analyses predict the existence of other rare haplotypes in Mayabeque Province. The most common haplotype for each genetic marker was identical to a D. nitens from Brazil, Colombia, Panama, and French Guiana. The star-like haplotype networks, each with a central (ie "ancestral") and most abundant haplotype, combined with the significant negative values for the Tajima's D and Fu's F tests, is consistent with a hypothesis of the introduction of D. nitens on horses from mainland South America (ie a founder effect) followed by demographic expansion. Additional population genetic studies on D. nitens are needed in other countries where this species occurs to examine the phylogeography of this tick species of socioeconomic importance.
Roblejo‐Arias et al. (Fri,) studied this question.