Acanthopharynx dormitata sp. n. and Desmodora bilacinia sp. n. are described from intertidal sediments of Wellington, North Island of New Zealand. Acanthopharynx dormitata sp. n. is characterised by a cephalic capsule with a crown of 14 setae (four cephalic and ten subcephalic setae) and 24 additional subcephalic setae arranged in eight longitudinal rows, unispiral amphidial fovea, buccal cavity with crown of denticles, and males with nine precloacal and two postcloacal supplements. Desmodora bilacinia sp. n. is characterised by eight subcephalic setae on the cephalic capsule, unispiral amphidial fovea, males with two precloacal supplements consisting of thin, rounded cuticular extensions and two rows of thick subventral setae extending from precloacal supplements to near tail tip, and non-annulated tail tip with perforations covering anterior third to two-thirds. The present study brings the total number of valid Acanthopharynx and Desmodora species to 13 and 35, respectively, and provides the first record of the genus Acanthopharynx in the New Zealand region. Preliminary analyses of phylogenetic relationships within the Desmodorinae and closely related Spiriniinae using SSU and D2-D3 of LSU molecular sequences indicate that both subfamilies are paraphyletic. Our results provide limited support for the monophyly of Acanthopharynx and Desmodora, for which two and six sequences, respectively, were included in the analyses. Acanthopharynx formed a basal clade to the Desmodorinae/Spiriniinae; however, in the SSU tree this basal clade also included D. communis and Zalonema sp. sequences. Further research is required to confirm the status and relationships of genera within the Desmodorinae and Spiriniinae.
