Phylogeny and character evolution of the marine mite genus Isobactrus (Acari: Halacaridae)

Abstract

A morphology-based phylogenetic analysis of the 24 species of Isobactrus (Acari: Halacaridae) demonstrated three major monophyletic groups supported by synapomorphies. Each group is geographically distinct being tropical Pacific, North Atlantic and Holarctic. Character optimization indicates some evolutionary tendencies of character transformation. Reduction of idiosomal lateral setation, loss of setae on the genu and the addition of female subgenital setae are postulated synapomorphies congruent throughout the tropical lineage. Similarly, setal addition on the telofemur occurred in the North Atlantic lineage, while reduction of genital area sclerotization is recognized in a northern phyletic group.

Keywords:

• Acari Character Evolution Halacaridae Isobactrus Morphology Phylogeny