First record of Ixodes (Scaphixodes) caledonicus in the Carpathian Basin and first time molecular-phylogenetic analysis of this tick species with updated host records and geographical range

Four Ixodes species represent the subgenus Scaphixodes Schulze, 1941 in Europe, but none of them were reported to be compared in a molecular-phylogenetic context. This study compensates for this lack of data. A tick larva, morphologically identified as Ixodes (Scaphixodes) caledonicus Nuttall, 1910, was collected from an Alpine swift (Tachymarptis melba) during its nesting period in Transylvania, Romania. Following DNA extraction, PCR analyses and sequencing in part with newly designed primers, three genetic markers of this specimen were amplified and compared to GenBank data, and two were analyzed phylogenetically. Based on sequence comparisons of its mitochondrial cytochrome c oxidase subunit I (cox1) and nuclear 28S rRNA genes I. caledonicus appeared to be closely related to members of the subgenus Pholeoixodes. However, the topology of the concatenated cox1 and 16S rRNA gene phylogenetic tree clearly showed its clustering with Ixodes (Scaphixodes) philipi. In conclusion, I. caledonicus is part of the tick fauna of Romania and is expected to occur also in other countries of the Carpathian Basin where rocky cliffs are available for nesting of swifts and other birds. This is the first species of the subgenus Scaphixodes in Europe, for which the traditional (morphology-based) taxonomic assignment is confirmed by molecular-phylogenetic analyses.