Two new species of Philometra Costa, 1845 (Nematoda: Philometridae) from Mycteroperca spp. (Serranidae) in the North-West Atlantic and northern Gulf of Mexico, USA.

Abstract

Based on light and scanning electron microscopical studies, two new species of Philometra Costa, 1845 (Nematoda: Philometridae) are described from two species of Mycteroperca Gill (Serranidae), marine perciform fishes, in coastal waters off Florida, USA: Philometra deburonae n. sp. from the inner side of operculum of the yellowfin grouper Mycteroperca venenosa (L.) and P. incognita n. sp. from the ovary of the gag M. microlepis (Goode & Bean). Philometra deburonae n. sp. is mainly characterised by the body length of males (1.90-2.38mm), the length of the spicules (78-84µm) and gubernaculum (54µm) and the presence of small outer cephalic papillae, a pair of fairly large caudal projections and the oesophageal gland extending anteriorly beyond the nerve-ring in subgravid females. Philometra incognita n. sp. is distinguished by the caudal mound consisting of two lateral reniform parts widely separated dorsally from each other, the absence of a pair of large papillae situated posteriorly to the cloaca, the shape and structure of the distal end of the gubernaculum plus the lengths of the spicules (117-141µm) and gubernaculum (60-81µm) in the male, the absence of caudal projections and the comparatively large larvae in the uterus (660-675µm long) of the gravid female, as well as, the body length of both males (2.45-3.11mm) and gravid females (120-180mm). The present descriptions of an additional two new philometrids increases the number of recorded nominal species of Philometra parasitising groupers (Serranidae) in the Gulf of Mexico to nine.