Branchiostegus sanae, a new species of deepwater tilefish (Eupercaria, Branchiostegidae) from the South China Sea

A new species of deepwater tilefish, <i>Branchiostegussanae</i> <b>sp. nov.</b>, is described based on five specimens collected from the area between the Xisha Islands and Hainan Island, China. This species can be distinguished from congeners by its unique cheek marker and a combination of characteristics. Among the tilefish species known to be distributed in the South China Sea, this species is the only one with vertical stripes on the body. Based on the <i>COI</i>, <i>CytB</i>, and <i>12S</i> sequences, a maximum-likelihood phylogenetic tree shows that the <i>B.sanae</i> <b>sp. nov.</b> forms a separate clade and is the sister group to the clade consisting of <i>B.sawakinensis</i>, <i>B.albus</i>, <i>B.argentatus</i>, <i>B.biendong</i>, <i>B.japonicus</i>, <i>B.auratus</i>, and <i>B.okinawaensis</i>. A key to the genus <i>Branchiostegus</i> is also compiled.