A new genus, Coomera, is erected to accommodate C. brayi new species, here described from the intestine and rectum of Monodactylus argenteus from southern Queensland, Australia. The species is characterised by a single gut caecum, conical pharynx, oblique testes, pars prostatica lined with anucleate vesicles, a large genital atrium, and a large muscular cirrus. Despite the single caecum, C. brayi is not assigned to the Monascinae for the following reasons: the sub-terminal oral sucker opens in a round aperture rather than a medial slit, the ventral sucker is larger than the oral sucker, a pre-pharynx is present, the pharynx is conical rather than elongate and the testes are symmetrical rather than tandem. These character states are shared with the Fellodistominae to which we assign this genus, suggesting that possession of a single caecum is homoplasious within the Fellodistomidae.