A new pontoniine shrimp, Rapipontonia paragalene n. gen., n. sp., is described from Nhatrang Bay, Vietnam. Rapipontonia n. gen. is morphologically most similar to Manipontonia Bruce, Okuno & Li, 2005. The two genera share the presence of long plumose setae on the coxa of the third maxilliped. Rapipontonia n. gen. can be distinguished from Manipontonia by the more elevated proximal half of the rostrum; the epigastric tooth being separated from the carapace by a suture; the presence of a single basal endite on the maxilla; the expanded caridean lobe on the first maxilliped; and the third maxilliped bearing a distinct suture between the ishiomerus and basis. The presence of long distoventral spines on the propodus and long curved simple dactylus forming together a grasping mechanism on the third to fifth pereiopods is an autapomorphy of the new genus. Periclimenes galene Holthuis, 1952 and P. platalea Holthuis, 1951 share most features with R. paragalene n. gen., n. sp. Therefore, these two species are transferred from Periclimenes Costa, 1844 to Rapipontonia n. gen.
Crustacea, Decapoda, Pontoniinae, symbiosis, hydroids, cnidarians, Vietnam, new species, new genus.