Species tree with the largest posterior probability from BPP v3.0 analyses conducted on Hydrobius specimens. Multi-locus data (COI, H3 and ITS2) used with H. convexus included as outgroup. Values above branches indicate range of split posterior probabilities, i.e. the probability for the node representing a speciation event, from four different prior-combinations. Values in red have split probabilities < 1.0. *Clade VII only delimited when specimens from Clade VII were a priori assigned as a potential species separate from H. arcticus and H. f. rottenbergii.