Four new free-living marine nematode species (Plectida: Ceramonematidae) and two new species records (Desmodorida: Desmodorinae) from Rangitāhua / Kermadec Islands, Aotearoa / New Zealand

Kermadec Islands is a remote subtropical island arc in the Southwest Pacific Ocean located 800–1000 km northeast of New Zealand’s North Island. Until now, no data was available on the nematode fauna living in the seafloor environments surrounding these islands. A single sample of subtidal coarse sediments from the Raoul Island coast yielded four new ceramonematid species: Ceramonema taikoraha sp. nov., C. taiora sp. nov., Metadasynemoides taihua sp. nov. and Pselionema huakita sp. nov. This new discovery is the first addition to the family since 2008 and brings the total number of valid ceramonematid species globally to 67 species. Dichotomous identification keys are provided for valid species of Ceramonema, Metadasynemoides and Pselionema. The desmodorid species Acanthopharynx dormitata and Desmodora bilacinia, were also recorded from Raoul Island some 1350 km away from their type locality in Wellington Harbour (New Zealand’s North Island). These species may have a relatively widespread distribution but testing this hypothesis will require further morphological comparisons and analyses of molecular sequence data to confirm the status of the Kermadec specimens.