During the course of a survey of fig-associated nematodes in eastern Australia, we discovered an unusual diplogastrid nematode that we describe herein as Teratodiplogaster fignewmani gen. nov., sp. nov. This nematode was isolated as adults and juveniles from the syconia of Ficus racemosa in Queensland and Western Australia. It is presumed to be associated with the agaonid fig wasp, Ceratosolen fusciceps, for dispersion to new phase-B sycones. Teratodiplogaster fignewmani gen. nov., sp. nov. was inferred to be the sister taxon to the genus Parasitodiplogaster based upon molecular phylogeny using nearly full-length sequences of the SSU and D2/D3 LSU ribosomal RNA genes. It is sufficiently distinct in morphology (with many autapomorphies) to justify a new monotypic genus with the hypothesis that further species of Teratodiplogaster gen. nov. will be discovered when sycones from other Ficus from tropical Australasia and possibly Africa are sampled.