Abstract Oziella sibirica sp. nov., collected from sedges (Cyperaceae: Carex macroura) in Siberia, Russia, is herein described based on the external morphology of all active instars using primarily conventional phase contrast microscopy, and on the female internal genitalia and prodorsal shield design using confocal laser scanning microscopy (CLSM) imaging and a 3D modelling technique. A partial mitochondrial COI gene sequence of O. sibirica sp. nov. is also provided, through GenBank, and this represents the first published record of any gene sequence data for the family Phytoptidae. We present remarks on the phylogenetic significance of the position of setae 3a in immature instars of eriophyoids and on the ontogenic variability of the empodium morphology of O. sibirica sp. nov. Using this species as a model, we propose a method for describing the internal genitalia of eriophyoids based on CLSM. We advocate the use of CLSM imaging as a new, relatively simple technique for observing and describing the internal