Opisthotrochopodus segonzaci, a new species of branchiate polynoid polychaete from the Lau and the North-Fiji Bac-arc Basins, southwestern Pacific Ocean, differs from the other species of the genus in having short dorsal cirri with rounded tips on the anterior segments and achaetous modified parapodia on segment 21.
Opisthotrochopodus trifurcus, a new species from the North-Fiji Basin, is unique in the genus in having trifurcate neurosetae on the posterior modified segment.