JKAU: Mar. Sci., Vol. 22, No. 1, pp: 45-64 (2011 A.D. / 1432 A.H.) DOI : 10.4197/Mar. 22-1.4 Digenetic Trematodes (Bucephalidae: Bucephalus Baer, 1827 and Rhipidocotyle Diesing, 1858) From Red Sea Fishes, Yemen Coast Ali B. Al-Zubaidy Department of Marine Biology and Fisheries, Faculty of Marine Science and Environment, Hodeidah University, Yemen Abstract. A total of 205 specimens of marine fish, belonging to four different species (60 Thunnus tanggol, 70 Sphyraena barracuda, 60 Lutjanus argentimaculatus,and15Carangiodes bajad) were examined for trematode parasites,especially Bucephalidae. Fishes were collected from local fish market in Hodeidah, during the period between September 2008 and July 2010. Three species of degenic trematodes were found, namely: 1- Bucephalus margaritae Ozaki and Ishibashi, 1934, belonging to Genus Bucephalus Baer, 1827.The digenetic trematode Bucephalus margaritae is described from the intestine and pyloric caecum of Sphyraena barracuda (English name: Barracudas) of family Sphyraenidae and from intestine of Carangoides bajad (English name: Jacks, Trevallies, and Scads) of family Carangidae. 2- Bucephalus varicus Manter, 1940. This parasite is described from the intestine of Carangoides bajad only. 3- Rhipidocotyle pentagonum (Ozaki, 1924) Eckmann, 1932 belonging to Genus Rhipidocotyle Diesing, 1858. The digenetic trematode Rhipidocotyle pentagonum is described from the stomach of fishes of family Scombridae (English name: Mackerels and tunas) Thunnus tanggol and Family of Lutjanidae (English name :Snappers/Jobfishes) Lutjanusargentimaculatus. 4- All species represent new records from the Red Sea,Yemen coastal water. 45 46 Ali B. Al-Zubaidy Introduction Fish parasites are important sentinels of environmental health (Arkoosh et al., 2004) because they can only thrive in systems with the proper suite of invertebrates to serve as intermediate hosts, the correct physical and chemical conditions, and the proper physiology in the final host. Parasites also can act to regulate aquatic populations (McCallum and Dobson, 1995) and may be as important as competition and predation in structuring animal communities (Minchella and Scott, 1991). Parasites have proven quite useful as natural tags in delineating fish stocks (Urawa et al., 1998), and can provide valuable information on the diet, feeding behavior, migration patterns, and systematic of fish populations (Marcogliese and Cone, 1997). During a lifetime, a fish parasite may pass through one or more intermediate hosts, one or more fish species, and often a final avian or mammalian host, making the parasite both a trophic marker and the top predator in the food web (Moles, 2007). Marine parasites are of immense ecological and economic importance. Almost groups of marine animals including the various invertebrates, fish, marine birds and reptiles, are hosts to parasites (Rohde, 2006). The parasite fauna of marine fishes and invertebrates is extremely rich and diverse and has the largest total biomass. Many parasites are highly pathogenic to their hosts, and may affect their number, reduce the quality of raw fish and fish products, or be harmful to a human (Korotaeva, 1973). Digenetic trematodes represent a large group of internal metazoan . Trematodes have complex life cycles, in which a mollusc serves as the first intermediate host and a vertebrate is usually the definitive host (Taskinen, 1998). According to Cribb et al. (2002) Digenea have over 100 families, well over 1000 genera and many thousands of species, many of them are of great importance to marine ecosystems (Korotaeva, 1973). Digeneids are important fish parasites with fishes serving both as intermediate and final hosts(about 5000 species of digeneans of fishes from 1115 genera). Adults range in size from <0.2 mm to >10 cm. They are permanent parasites in most marine fishes, and in many freshwater fishes, amphibians, reptiles, mammals and birds(Bray, 1984). Larval stages occur in a variety of invertebrates and vertebrates. Its usually Digenetic Trematodes (Bucephalidae: Bucephalus Bear, … 47 occur in either the intestine, stomach or mouth, or occasionally lungs and other organs, (Larval forms occur in almost any tissue). The epipelagic zone is a peculiar and very interesting biotope parasitologically. The most abundant of them are digeneids (Pozdnyakov, 1981). Trematodes of the families Bucephalidae; Allocreadiidae; Opecoelidae; Lepocreadiidae; and Fellodistomidae are not common for the pelagic zone, but are found there occasionally. Buron and Morand (2002) reported that 57% of metazoan parasites in waters deeper than 1000 meter were digeneans, 25% crustaceans (80% copepods), 10% cestodes, 4% acanthocephalans, 2% nematodes and 2% monogeneans. Protistans (in which they included the myxozoans) make up less than 17% of parasite records. The Red Sea, an important offshoot from the Indian ocean, has a very rich and varied fish fauna (Saoud and Ramadan, 1983). The Literature on the parasites of Red Sea fishes, particularly helminths, is relatively limited, several papers on the trematodes of the Red Sea fishes were published by (Nagaty, 1954; Nagaty and Abdel-Aal, 1962; Saoud and Ramadan,1983; Hassanine and Gibson, 2005 a & b; Al- Zubaidy, 2010, and Al-Jahdali, 2010 ). Materials and Methods A total of 205 specimens of marine fish, belonging to four different species (60 Thunnus tanggol, 70 Sphyraena barracuda, 60 Lutjanus argentimaculatus, and 15 Carangiodes bajad) were examined for trematode parasites, especially Bucephalidae. Fishes were collected from local fish market in Hodeidah, during the period between September 2008 and July 2010. Standard parasitological techniques were used to examine the alimentary canal of the fish. Trematodes were removed from their host fishes under a dissecting microscope and observed live under a compound microscope. Some worms were fixed in alcohol-formalin- acetic acid (AFA) under a slight cover slip pressure and preserved in 75% ethyl alcohol. Whole-mounts were stained in alum carmine, cleared in lactophenol and mounted in Canada balsam. Trematodes were identified to species level based on the keys of Skrjabin et al. (1964), Yamaguti (1971), Schell (1985), Gibson and Bray (2002), and With the help of Prof. Dr. Bray and Prof. Dr. Fabiana. 48 Ali B. Al-Zubaidy Results and Discussion Parasitological investigation of 205 specimens of four species of marine fishes (Thunnus tanggol, Sphyraena barracuda, Lutjanus argenti- maculates, and Carangoides bajad ) revealed 3 species of parasites: Bucephalus margaritae Ozaki et Ishibashi, 1934; Bucephalus varicus Manter,1940 and Rhipidocotyle pentagonum (Ozaki, 1924) Eckmann, 1932. Rhipidocotyle pentagonum (Ozaki, 1924) Eckmann, 1932 Bucephalus margaritae Ozaki et Ishibashi, 1934 Bucephalus varicus Manter,1940 . Classification: Infrakingdom: Platyzoa Cavalier-Smith,1998 Phylum: Platy helminthes Gegenbaur,1859 Subphylum: Neodermata (Ehlers,1985)Cavalier-Smith,1998 Infraphylum: Trematoda (Rudolphi,1808) Cavalier-Smith, 1998 Class: Trematoda Rudolphi 1808 Subclass: Digenea Carus 1863 Super order: Anepitheliocystidia La Rue, 1957 Order: Strigeatoidea La Rue, 1957 Suborder: Brachylaimata Super family: Bucephaloidea La Rue, 1926 Synonyms: Gasterostomatiformes Skrjabin et Schulz, 1937 Gasterostomata (Odhner, 1905) Skrajabin et Schulz, 1937 Alcicornata Skrjabin et Schulz, 1937 Family: Bucephalidae Poche, 1907 Subfamily: Bucephalinae Poche, 1907 Genus:Bucephalus Baer,1827 Synonyms: Gasterostomum Siebold, 1848 Eubucephalus Diesing, 1855 Labratrema Maillard, 1975 -Bucephalus margaritae Ozaki et Ishibashi, 1934 -Bucephalus varicus Manter,1940 . Genus: Rhipidocotyle Diesing, 1858 Synonyms: Nannoenteron Ozaki,1924 Nannoenterum Ozaki,1928 Pararhipidocotyle Kohn,1970 Digenetic Trematodes (Bucephalidae: Bucephalus Bear, … 49 Rhipidocotyle pentagonum (Ozaki, 1924) Eckmann, 1932 Bucephalus margaritae Ozaki et Ishibashi, 1934 Bucephalus varicus Manter,1940 . 1-Bucephalus margaritae Ozaki and Ishibashi, 1934 (Fig.1). 1.1. Description and Measurements (in µm) (base on 4specimens) Body: Its length varies from 343.0 to 834.5 (mean 533.7 ± 121.3) and 58.2 to 170.1(87.1 ± 18.1) width. Spined tegument, with small spines all over the body. Rhynchus: 112 in diameter, Funnel-like apical, with concave bottom and seven marginal tentacles, each one is divided in its basal part into two branches. Mouth: middle third of body. Oral sucker: post equatorial, circular, muscular, 349.5 ± 20.2 (229.3 – 556.1) from the anterior extremity. Pharynx: Small, rounded, 39-52(43± 2.1). Esophagus: Short, surrounded by glandular cells. Vitellaria: Numerous rounded, distributed in the median equatorial body region and laterally in two convergents camps, with 14 to 18 each side. Intestine: simple, sac shaped. Ovary: globular, rounded, 32.0± 9. 4 (24.5 – 46.1) long and 54.0 (36.0 – 117.3) wide. smooth edges, slightly right and located between the rear edge of the blind bowel and anterior testis. Glands: Mehlis gland and Laurer´s canal not evidenced. Uterus: Winding, which can reach the third front of the body and then reaches the region intertesticular. Uterine loops exceed the anterior limit of vitellaria and posteriorly reaches the body´s posterior extremity. Uterus final portion and partially involves the cirrus inside´s genital atrium. Testes: 2, rounded, smooth edges, posterior to oral sucker, one after the other or slightly oblique to each other, globular with 41.0 ± 9.7 (34.0 – 64.2) long and 26.7 ± 6.6 (20.2 – 44.1) wide (anterior) and 36.4 (22.3 – 82.2) long and 38.5