The Ixodes ricinus complex (Acari: Ixodidae) in the Southern Cone of America: Ixodes pararicinus, Ixodes aragaoi, and Ixodes sp. cf. I. affinis.

SARACHO-BOTTERO, MARÍA N.; VENZAL, JOSÉ M.; TARRAGONA, EVELINA L.; THOMPSON, CAROLINA S.; MANGOLD, ATILIO J.; BEATI, LORENZA; GUGLIELMONE, ALBERTO A.; NAVA, SANTIAGO

PARASITOLOGY RESEARCH

SPRINGER

Lugar: Berlin; Año: 2019

0932-0113

The goal of this study was to clarify the taxonomic status of the Ixodes ricinus complex in the Southern Cone of America, byusing morphological characters and molecular markers (mitochondrial 16SrDNA and cox1 genes). The morphological analysisindicates that three different taxa of the I. ricinus complex occur in this region: Ixodes pararicinus, Ixodes aragaoi, and Ixodes sp.cf. I. affinis. The most prominent diagnostic character among them is the size of scutal punctations in both male and female ticks.In themales of Ixodes sp. cf. I. affinis, the punctations on the central field and along themedianmarginal groove of the scutum areclearly larger than in the males of I. aragaoi and I. pararicinus, while the punctations of I. aragaoi are larger but less numerousthan in I. pararicinus. The punctations in Ixodes sp. cf. I. affinis females are larger and deeper than in females of I. aragaoi andI. pararicinus, and those of I. aragaoi are slightly larger than in I. pararicinus. The length of the lateral posterior denticles of themale hypostome is comparatively longer in I. aragaoi than in the other two species, and longer in Ixodes sp. cf. I. affinis than inI. pararicinus. In the 16S analysis, I. pararicinus and I. aragaoi are monophyletic (99% and 98% bootstrap support, respectively),while Ixodes cf. I. affinis does not represent a single lineage. In the cox1 analysis, both I. pararicinus and I. aragaoi are welldefinedtaxa, but the bootstrap support for Ixodes sp. cf. I. affinis is low (67%). In general, there are considerable 16SrRNAdifferences among lineages of Ixodes sp. cf. I. affinis from different geographical areas. These results may be indicative of theexistence of different species. The populations morphologically compatible with I. affinis from Argentina, Colombia, Panama,Belize, and USA should be provisionally named as Ixodes sp. cf. I. affinis until an integrative taxonomic work with furtherevidence redefines whether or not this taxon actually represents a species complex.