Two new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) from marine fishes off the northern coast of Australia

Based on light and electron microscopical studies, two new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) are described from the ovary of marine perciform fishes off the northern coast of Australia (near Darwin): Philometra carangis n. sp. from the bluespotted trevally Caranx bucculentus Alleyne & Macleay (Carangidae) and P. carponotati n. sp. from the Spanish flag snapper Lutjanus carponotatus (Richardson) (Lutjanidae). Philometra carangis is mainly characterised by the length of the spicules (153–189 µm), the presence of a distinct dorsal protuberance consisting of two dorsolateral lamellar parts separated from each other by a smooth median field, a V-shaped mound on the male caudal extremity, a pair of large post-cloacal papillae and the body length of the males (3.22–4.15 mm). Philometra carponotati is distinguished from other congeneric species parasitising lutjanids by the length of the spicules and gubernaculum (225–252 and 99–117 µm, respectively), the absence of a dorsal protuberance on the distal lamellar part of the gubernaculum, the presence of a U-shaped mound on the male caudal extremity, a pair of large post-cloacal papillae and the body length of the male (3.74–4.31 mm). Besides the recently established Philometra zabidii Moravec & Diggles, 2014 (based on a single female), these two newly described nematodes are the only nominal gonad-infecting species of Philometra known to parasitise marine fishes in Australian waters.