We describe a box jellyfish, Tripedalia maipoensis sp. nov., based on samples collected from a shrimp pond in Hong Kong. This new species is morphologically distinct from other species of the family Tripedaliidae by the following combination of characters: (1) three pedalia at each bell corner; (2) each pedalium with one tentacle; and (3) velarium with forked canals. Phylogenetic analyses based on a concatenated dataset of the 16S, 18S and 28S rRNA genes show that T. maipoensis sp. nov. is sister to the morphologically similar species T. cystophora, but the two species exhibit 17.4% divergence in the 16S rRNA gene, supporting T. maipoensis sp. nov. as a distinct species. This new species represents the fourth described species of Tripedaliidae, and the first record of the family in Chinese coastal waters.
Keywords: Box jellyfish; Hong Kong; Morphology; Phylogeny; Tripedalia.