Two species representing a rare genus Sinaxonopsis (Acari, Hydrachnidiae, Aturidae) from China, with discussion of some taxonomic features

Sinaxonopsis Yi and Jin, 2012 was erected based on S. unicucrus from China. In this paper, one more species new to science, Sinaxonopsis hainanensis sp. nov. is described from China. Sinaxonopsis unicucrus Yi and Jin, 2012, is redescribed with more details, including information on the glandularia and patches of the large posterior dorsal plate, among others. Using scanning electron microscope (SEM) images, this work has clarified that the dorsoglandularia D₄ do indeed have glands, and that the phenomenon of missing glands is absent on the dorsal plate of Sinaxonopsis, which occurs in some genera of Aturidae. Sixteen pairs of glandularia and two pairs of ocularia of Sinaxonopsis are consistent with the common patterns in water mites.