Recent parasitological examinations of the marine perciform fish (tigerteeth croaker) Otolithes ruber (Bloch et Schneider) (Sciaenidae) from off Iran yielded one new and one previously known nematode species: Dichelyne (Dichelyne) spinigerus sp. nov. (Cucullanidae) from the host’s intestine in the Persian Gulf and Philometra otolithi Moravec et Manoharan, 2013 (Philometridae) from the ovary in the Persian Gulf and the Sea of Oman. The new species D. spinigerus is mainly characterized by the tail tip of both sexes terminating in two shaply pointed spikes (one dorsal and one ventral) and bearing a pair of minute lateral cuticular spines at its base, situation of both deirids and the excretory pore well posterior to the level of the posterior end of oesophagus, absence of a precloacal sucker and the presence of one or two intestinal caeca. The male and small mature females of the gonad-infecting species P. otolithi are described for the first time, based on light and scanning electron microscopical studies. The male of P. otolithi is most similar to that of P. johnii Moravec et Ali, 2013, but differs from it by the structure of the cephalic end and the number of caudal papillae; both species also differ from each other by the presence of transverse lamellae in the buccal cavity of gravid and subgravid females of P. otolithi, which are missing in those of P. johnii.

Two philometrid nematodes (Philometridae) are described from the marine perciform fish (tigertooth croaker) Otolithes ruber (Bloch & Schneider) (Sciaenidae) from off Iran: Clavinemoides annulatus n. g., n. sp. based on female specimens from the caudal fin of fish from the Persian Gulf and Philometra otolithi Moravec & Manoharan, 2013 from subgravid and nongravid females collected from the ovary of fishes in the Sea of Oman and the Persian Gulf. The monotypic genus Clavinemoides n. g. is mainly characterised by a triangular oral aperture, a markedly large anterior oesophageal bulb, a distinctly annulated body and numerous fine elevated transverse cuticular bands. The finding of P. otolithi in Iranian waters represents a new geographical record of this parasite species. An updated key to the genera of the Philometrinae Baylis & Daubney, 1926 is provided.