Abstract
A new monospecific genus of the family Nannopodidae Brady, 1880 is proposed, based on specimens of both sexes of Concilicoxa hispida gen. et sp. nov. collected from subtidal sandy sediments in the Yellow Sea of South Korea. The presence of a coxal outer projection on the first to fourth legs and reduction of both rami of the second to fourth legs in this new genus show a clear relationship with a clade, which is characterised by the modified thoracopods for burrowing ability, comprising Huntemannia Poppe, 1884, Rosacletodes Wells, 1985, Laophontisochra George, 2002, Acuticoxa Huys & Kihara, 2010 and Talpacoxa Corgosinho, 2012 in Nannopodidae. Within this clade, C. hispida gen. et sp. nov. is most closely related to L. maryamae George, 2002 in having the prehensile endopod in the first leg, broad intercoxal sclerite on the second to fourth legs and the female fifth leg being composed of separate exopod and baseoendopod, but is distinguished by the absence of mandibular exopod, two-segmented mandibular endopod, presence of four setae on the distal exopodal segment of the first leg, and fusion of the intercoxal sclerite to the coxae in the third and fourth legs. These four features are considered as autapomorphies of the new genus. The possible relationship amongst members of the nannopodid clade is further discussed. Additionally, some comments on the taxonomic position of L. terueae Björnberg, 2014 are given, resulting in the transfer of the species to Acuticoxa as A. terueae comb. nov.