Promonhystera papilla sp. nov.

(Figures 1–2, Table 1)

Type material. Holotype: one male on slide Sanya 01, Paratypes: two males and one juvenile on slide Baimajing 04.

Type locality and habitat. Holotype sampled in sublittoral of Sanya City, Hainan Province (19°54′09″N, 109°31′44″E), water depth about 5 m, muddy sediment and 0–2 cm section in the corer . Paratypes sampled in the intertidal zone of Baimajing, Hainan Province (19°57′46″N 110°25′48″E), muddy sediment and 0–2 cm section in the corer .

Etymology. The Latin adjective papilla refers to the distinct feature which males have: papilliform supplements.