A new species of Philometra (Nematoda, Philometridae)
from the gonads of the rock hind Epinephelus adscensionis
(Osteichthyes) from the southern Gulf of Mexico
František Moravec
1*
and Guillermo Salgado-Maldonado
2
1
Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, BraniovskÆ 31, 370 05 ¨eskØ Budjovice,
Czech Republic;
2
Instituto de Biologa, Universidad Nacional Autnoma de MØxico (UNAM), A.P. 70-153, 04510 MØxico, D.F., Mexico
Abstract
A new species of parasitic nematode, Philometra mexicana sp. nov. (Philometridae), is described based on males and females
parasitizing the gonads of the marine perciform fish (rock hind) Epinephelus adscensionis (Osbeck) (Serranidae) off the coast
of the southern Gulf of Mexico (reefs of the Enmedio Island, Veracruz), Mexico, collected on 10 April 1990. The new species
is characterized mainly by very small males (body length 1.631.86 mm) with equally long, needle-like spicules (length 90120
m) and the gubernaculum (5766 m) without the usual dorsal barb on the distal end, the body length of gravid females
(178230 mm), the presence of a well-developed anterior bulbous inflation on the female oesophagus, and by the length of the
first-stage larvae (420435 m). A comparison with other congeners parasitizing the gonads of marine fishes is provided. The
cephalic end of the gravid female of Philometra margolisi Moravec, Vidal-Martnez et Aguirre-Macedo, 1995, another relat-
ed species from the gonads of Epinephelus [E. morio (Valenciennes)] in Mexico, has been studied by SEM for the first time;
it confirms the arrangement of the cephalic papillae as reported in the original species description. Philometra mexicana is the
fifth species of Philometra reported from the gonads of marine fishes in the West Atlantic region.
Keywords
Parasitic nematode, Philometra, gonads, marine fish, Epinephelus, Mexico
*
Corresponding author: moravec@paru.cas.cz
Introduction
Species of Philometra Costa, 1845 parasitic in the gonads of
marine fishes are widely distributed mainly in the tropical and
subtropical regions of the Atlantic, Indian and Pacific Oceans
(Moravec 2006). Although the large-sized females of these
nematodes may cause serious damage to the fish ovaries and
may thus affect fish reproduction (Hine and Anderson 1982,
Sakaguchi et al. 1987, Moravec et al. 2003), the fauna of these
important parasites remains poorly known. Parasitological ex-
aminations of some marine fishes, carried out by the research
team of G. Salgado-Maldonado in Mexico at the beginning of
the 90s, revealed the presence of Philometra specimens in the
gonads of the wild rock hind, Epinephelus adscensionis
(Osbeck) (Serranidae, Perciformes), off the southern Gulf of
Mexico (reef of the Enmedio Island, Veracruz), Mexico. A
detailed study of their morphology by both light (LM) and
scanning electron microscopy (SEM) shows that they repre-
sent a new species, described below.
Epinephelus adscensionis is a tropical marine fish (up to
61 cm long) distributed in both the Western Atlantic (Mas-
sachusetts, USA, Bermuda to Gulf of Mexico, the Caribbean
and southern Brazil) and the Eastern Atlantic (Ascension and
St. Helena Islands) (Froese and Pauly 2007).
Materials and methods
The fish were collected by local fishermen. The gonads were
dissected out from fish and were fixed in 10% formaldehyde
solution. Later, the fixed fish ovaries were placed in water for
an hour and subsequently they were cut open and examined
for the presence of philometrids under the dissecting micro-
scope. The nematodes recovered were washed in physiologi-
cal saline and then re-fixed in 4% formaldehyde solution. For
light microscopical examination, the nematodes were cleared
with glycerine. Drawings were made with the aid of a Zeiss
drawing attachment. Specimens used for scanning electron
Stefaæski
DOI: 10.2478/s11686-007-0044-x
© 2007 W. Stefañski Institute of Parasitology, PAS
Acta Parasitologica, 2007, 52(4), 376–381; ISSN 1230-2821
Unauthenticated
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