A new species of the genus <i>Aphotopontius</i> Humes, 1987 (Siphonostomatoida, Dirivultidae) from a vent field at the Southeast Indian Ridge

During INDEX 2018 on a cruise as part of the Indian Ocean Exploration project in the area of the German exploration license for polymetallic sulfide deposits, a new species of Aphotopontius Humes, 1987 was collected. To date, there are 12 described species of the genus Aphotopontius found in deep sea hydrothermal vent fields around the world, with 3 species occurring in the Indian Ocean: A. kiost Lee J, Kim D & Kim IH, 2020, A. muricatus Lee J, Kim D & Kim IH, 2020 and A. limatulus Humes, 1987. The new species Aphotopontius ilianae sp. nov. shares most characters with its congeners but in particular with A. mammillatus Humes, 1987 and A. acanthinus Humes & Lutz, 1994, the presence of mammilliform processes on the basis of leg 1 and with A. kiost, the unsegmented leg 5 and endopod-1 of the maxilliped, armed with three setae. Confocal laser scanning microscope images and mtCOI barcoding complement the traditional taxonomic description. The present research not only describes a new species of Aphotopontius and extends the distribution of the genus to the Southeast Indian Ridge, but also provides 40 new sequences of dirivultids to the National Center for Biotechnology Information (NCBI) and explores the connectivity of multiple species of the genus.