Two new species of Philometra (Nematoda: Philometridae) parasitic in the perciform fish Cynoscion nebulosus (Sciaenidae) in the estuaries of South Carolina, USA

Abstract

Abstract.Two new nematode species of Philometra Costa, 1845, P. carolinensis sp. n. and P. cynoscionis sp. n., are described from the spotted seatrout, Cynoscion nebulosus (Cuvier) (Sciaenidae, Perciformes) in estuaries on the Atlantic coast of South Carolina, USA. Philometra carolinensis (males and gravid and subgravid females) parasitic in the host's ovary is most similar to P. lateolabracis (Yamaguti, 1935) in female morphology, but distinctly differs from it in possessing conspicuously short spicules (81-87 µm long) with heavily sclerotized distal parts, the gubernaculum bearing a reflected dorsal barb, and in the length ratio of the gubernaculum and spicules (1:1.23-1.42) in the male. Philometra cynoscionis (only gravid females) found subcutaneously in the host's tissue (lateral to the ascending process of the premaxilla and also posteromedial to the length of each maxilla) is characterized mainly by the presence of cephalic papillae arranged in two circles (8 large papillae in outer circle and 6 small papillae in inner circle), the absence of caudal projections, the body size (length of gravid female 20-33 mm) and the location in the host.During recent investigations into the parasites of fishes in the estuarine systems on the Atlantic coast of South Carolina carried out by the research team of one of the authors (I. de Buron), the spotted seatrout Cynoscion nebulosus (Cuvier) was found to harbour philometrid nematodes located in the ovaries and in the subcutaneous tissue of the head (lateral to the ascending process of each premaxilla, and posteromedial to each maxilla). These proved to represent two previously undescribed species of the genus Philometra Costa, 1845, which are described herein.Cynoscion nebulosus is an important food and sport fish (up to 1 m long and 7 kg weight) inhabiting estuaries of rivers and shallow coastal waters, distributed in the West Atlantic from New York to Florida and in the entire Gulf of Mexico (Froese and Pauly 2005). MATERIALS AND METHODSSpotted seatrout were collected using trammel netting during daytime ebbing tides primarily over mud and oyster shell substrates adjacent to the marsh (<2 m depth). Fish were measured, placed on ice and transported to the laboratory for immediate dissection. Nematodes recovered were washed in physiological saline and then fixed in 70% ethanol or in 4% or 10% formaldehyde solution in physiological saline. Some specimens were fixed and stored in 95% ethanol for subsequent DNA examination. For light microscopy, specimens were cleared with glycerine. Drawings were made with the aid of a Zeiss drawing attachment. After examination, male specimens were mounted in glycerine-jelly as slides, female specimens were maintained in 70% ethanol in vials. Specimens used for scanning electron microscopy (SEM) were transferred to 4% formalin and then postfixed in 1% osmium tetroxide, dehydrated through a graded ethanol series, critical point dried and sputter-coated with gold; they were examined using a JSM-6300 scanning electron microscope at an accele...

Some gonad-infecting species of Philometra (Nematoda, Philometridae) from offshore fishes of South Carolina and Georgia, USA, including Philometra charlestonensis sp. nov. from the scamp Mycteroperca phenax

“…Posterior end of intestine atrophied, forming narrow ligament attached ventrally to body wall near posterior extremity. Posterior end of body rounded, 95 wide, with pair of very Remarks: The gross morphology and measurements of this specimen resemble those of gravid females of Philometra carolinensis Moravec, de Buron et Roumillat, 2006, a gonadinfecting philometrid recently described from another sciaenid fish, Cynoscion nebulosus (Cuvier), from South Carolina estuaries , except for the presence of minute caudal projections. Species identification will only be possible when conspecific males are obtained from M. undulatus.…”

“…Of all these species, only five have been reported from the Western Atlantic: Philometra carolinensis Moravec, de Buron et Roumillat, 2006 from Cynoscion nebulosus (Cuvier) (Sciaenidae) in the USA (South Carolina); P. lateolabracis (Yamaguti, 1935) (Rees 1970;Crisp and Klein 1973;Ramachandran 1973;Martínez and Ventosa 1982;Moravec et al 1995Moravec 2006). Linton (1901Linton ( , 1907) also reported Philometra globiceps (Rudolphi, 1819) from five fish species belonging to the Belonidae, Lobotidae, Megalopidae, Pomatomidae and Scombridae off the USA (Massachusetts) and Bermudas, but this identification is doubtful (Petter andRadujkoviae 1989, Moravec 2006).…”

“…Results of the systematic-taxonomic and ecological evaluation of these parasites from freshwater centrarchids and some estuarine fishes (Paralichthys lethostigma Jordan et Gilbert and Cynoscion nebulosus (Cuvier)) have been published by Golléty et al (2005), Moravec and de and . Of a total of seven philometrid species recorded, only one, Philometra carolinensis Moravec, de Buron et Roumillat, 2006 from C. nebulosus, is a parasite of fish gonads. Three additional gonad-infecting species of Philometra, including one new to science, have been found in the recently examined scamp Mycteroperca phenax (Jordan et Swain) (Serranidae), bluefish Pomatomus saltatrix (Linnaeus) (Pomatomidae) and Atlantic croaker Micropogonias undulatus (Linnaeus) (Sciae-nidae).…”

A new species of Philometra (Nematoda, Philometridae) from the gonads of the rock hind Epinephelus adscensionis (Osteichthyes) from the southern Gulf of Mexico

“…Of them, only four have been reported from the Western Atlantic: Philometra carolinensis Moravec, de Buron et Roumillat, 2006 from Cynoscion nebulosus (Cuvier) (Sciaenidae) in the USA (South Carolina); Philometra lateolabracis (Yamaguti, 1935) from several fish species of different families in Bermuda, Cuba and Brazil; Philometra margolisi Moravec, Vidal-Martínez et Aguirre-Macedo, 1995 from Epinephelus morio (Valenciennes) (Serranidae) in Mexico (Gulf of Mexico); and Philometra saltatrix Ramachandran, 1973 from Pomatomus saltatrix (Linnaeus) (Pomatomidae) in the USA (Connecticut) (Rees 1970;Crisp and Klein 1973;Ramachandran 1973;Martínez and Ventosa 1982;Moravec 2006;Moravec et al 1995Moravec et al , 2006. Linton (1901Linton ( , 1907) also reported Philometra globiceps (Rudolphi, 1819) from five fish species belonging to the Belonidae, Lobotidae, Megalopidae, Pomatomidae and Scombridae in the USA (Massachusetts) and Bermudas, but this identification is doubtful (Petter andRadujkoviae 1989, Moravec 2006).…”

Philometra dissimilis n. sp. from the ovary of Johnius belangerii (Sciaenidae) and other new records of philometrids (Nematoda: Philometridae) from fishes of the Bay of Bengal, India

“…To date, the following six nominal gonad-infecting species of Philometra have been reported from fi shes of the family Sciaenidae: P. carolinensis Moravec, Yamaguti, 1941 from Pennahia argentata (Houttuyn) off Japan (Yamaguti, 1941;Moravec et al, 1998Moravec et al, , 2006Moravec et al, , 2010Quiazon et al, 2008a;Moravec & de Buron, 2009Moravec & Manoharan, 2013;Moravec & Diggles, 2014b;Moravec & Barton, 2015). Moreover, P. lateolabracis (Yamaguti, 1935), a specifi c parasite of the Lateolabracidae, was reported from fi shes belonging to six genera of the Sciaenidae (see Moravec, 2006;Quiazon et al, 2008b), but, in the view of the paper by Quiazon et al (2008b), the nematodes from these hosts were evidently misidentifi ed.…”