A new species of the rare genus Segonzackomaius Burukovsky, 2011 (Decapoda, Caridea, Nematocarcinidae) from the Northwest Pacific

A recently collected specimen of the rare deep-sea nematocarcinid genus Segonzackomaius Burukovsky, 2011 from the Philippine Basin is new to science and we revealed that the material previously reported as S. altus (Spence Bate, 1888) from Taiwan also belongs to this new species, based on a DNA sequence comparison. The new species S. sursus sp. nov. differs from S. altus by having a relatively shorter but ascending rostrum, and a longer telson, which distinctly exceeds the uropodal endopod. An identification key to the three known species of Segonzackomaius is provided. The multi-gene analyses do not support the monophyly of Nematocarcinus A. Milne-Edwards, 1881 because S. sursus sp. nov. forms a robust clade with N. lanceopes Spence Bate, 1888 and this clade is very separated from other species of Nematocarcinus. Nevertheless, a more extensive molecular study on the phylogenetic relationships amongst the taxa within the family Nematocarcinidae Smith, 1884 is necessary for a better comprehension of its evolution.