Gravid females of the little-known dracunculoid nematode Mexiconema liobagri Moravec et Nagasawa, 1998 (Daniconematidae), a parasite of the rare endemic catfish Liobagrus reinii Hilgendorf (Amblycipitidae), were found in the body cavity of this fish from two new localities in Japan: the Takami River at Kotsugawa, Higashiyoshino, Nara Prefecture and the Tenryu River at Ina, Nagano Prefecture, representing the second record of this nematode species since its original description. Light and scanning electron microscopical examinations of these specimens enabled us to supplement the original description of M. liobagri and to recognise biometrical variability in this species. Details of the cephalic structure of M. liobagri (presence of the small triangular mouth armed with six denticles, surrounded by a pair of large lateral amphids and four submedian pairs of small cephalic papillae) are described for the first time. In addition to M. liobagri, another specific nematode parasite, Rhabdochona japonica Moravec, 1975, was recorded in the intestine of L. reinii from the Takami River.
Two little-known nematode species of the family Camallanidae, intestinal parasites of marine perciform fishes, are reported from off New Caledonia: Procamallanus (Procamallanus) annulatus Yamaguti, 1955 from the goldenlined spinefoot Siganus lineatus (Valenciennes) (Siganidae) and Procamallanus (Spirocamallanus) monotaxis (Olsen, 1952) from the longspine emperor Lethrinus genivittatus Valenciennes and the slender emperor Lethrinus variegatus Valenciennes (both Lethrinidae). Detailed light and electron microscopical studies (the latter used for the first time in these species) revealed some taxonomically important, previously not observed features, such as the presence of deirids, six crescent-shaped elevations surrounding the mouth, three poorly developed protuberances on the female tail tip and circumcloacal papillae and phasmids on the male tail in P. annulatus, and the presence of a circumoral flange, only 12 (instead of 14 reported) cephalic papillae, the shape of deirids and similar numbers (14–17 and 14–15) of spiral ridges in the male and female buccal capsules in P. monotaxis. The fourth-stage larva of P. annulatus is described for the first time. Firststage larvae of both species were found to possess several digital processes at the tail tip. The present findings represent new host and geographical records of these parasite species.
Based on light and scanning electron microscopical studies, a new gonad-infecting species of Philometra Costa, 1845, P. dissimilis n. sp. (Nematoda: Philometridae), is described from the marine fish (Belanger’s croaker) Johnius belangerii (Cuvier) (Sciaenidae, Perciformes) in the Bay of Bengal, off the eastern coast of India. The species is mainly characterized by the body length of male 2.73 – 3.37 mm and that of gravid female 145 – 171 mm, needle-like, equal spicules 96 – 120 μm long, length of the gubernaculum 75 – 90 μm, distal end of the gubernaculum with lamellar structures forming a simple dorsal protuberance and by the V-shaped male caudal mound. Philometra dissimilis is the seventh known gonad-infecting species of this genus parasitizing sciaenid fishes. Moreover, an additional two species of Philometra (only females) were recorded from fishes in the Bay of Bengal: P. lobotidisMoravec, Walter et Yuniar, 2012 from the abdominal cavity of Lobotis surinamensis (Bloch) (Lobotidae, Perciformes), which is a new geographical record, and Philometra sp. from the ovary of Platycephalus indicus (Linnaeus) (Platycephalidae, Scorpaeniformes), representing probably an undescribed species.
A new nematode species, Raphidascaris (Ichthyascaris) arii sp. n. (Anisakidae), is described from male and female specimens found in the intestine of two species of marine siluriform fishes, the spotted catfish Arius maculatus (Thunberg) (Ariidae) (type host) and the striped eel catfish Plotosus lineatus (Thunberg) (Plotosidae) from the coastal region of the Gulf of Thailand, Thailand. Based on light and scanning electron microscopy examinations, the new species differs from other nine representatives of the subgenus Ichthyascaris Wu, 1949 mainly in the length of spicules (210–333 μm), body length of gravid females (10–17 mm), and in the presence of small cuticular spines or protuberances on the tail tip of both sexes and 21–30 pairs of preanal and 8 pairs of postanal papillae in the male. This is the first species of this subgenus reported from fishes of the order Siluriformes and the first species of the subgenus Ichthyascaris Wu, 1949 recorded from the Gulf of Thailand.
A male specimen of Dracunculus (Nematoda: Dracunculidae), collected in 1973 from the lung of the Papuan olive python Apodora papuana (Peters et Doria) and now deposited in the helminthological collection of the Natural History Museum in London, is identified as Dracunculus mulbus Jones et Mulder, 2007, a species recently described from the water python Liasis fuscus Peters in northern Australia. Apodora papuana is a new host record for D. mulbus and Papua New Guinea is apparently a new geographical record.
F. Moravec, A. Halajian, S. Tavakol, I. Nyagura and W. J. Luus-Powell
A new nematode species, Philometroides khalili n. sp. (Philometridae), is described from female specimens recovered from the operculum of the freshwater cyprinid fish Labeo rosae Steindachner (Cyprinidae, Cypriniformes) caught in the Bubi River, Zimbabwe. Based on light and scanning electron microscopical examination, the new species mainly differs from the only other African congeneric species P. africanus Moravec et Van As, 2001 in the body shape (filiform), length of gravid female (56 - 71 mm), in possessing a large oesophageal gland with a conspicuously large cell nucleus and in the shape (transversely oval), size (up to 33 - 36 μm high) and distribution of cuticular bosses. From other congeners it differs by a combination of morphological and biometrical features
A new nematode species, Buckleyella ornata n. sp. (Philometridae), is described from female specimens found in the abdominal cavity (mesenteries) of the talang queenfish Scomberoides commersonnianus Lacepède (Carangidae, Perciformes) caught in Darwin Harbour, northern Australia. Based on light and scanning electron microscopical examination, the new species mainly differs from the only other congeneric species B. buckleyi Rasheed, 1963 in having a markedly shorter oesophagus (2.04–2.75 mm long), by the absence of a cephalic mound around the mouth aperture, by the presence of four submedian cephalic papillae of the inner circle, and by a somewhat different arrangement of cuticular ornamentations on the body surface. Three protruding oesophageal teeth and large, dome-shaped cephalic papillae of the external circle present in the smallest gravid female of B. ornata are atrophied in larger conspecific gravid females. Buckleyella ornata is the first known nominal species of a philometrid parasitizing carangid fishes in Australian waters.
F. Moravec, H. Taraschewski, D. Appelhoff and O. Weyl
A new species of ascaridoid nematode, Hysterothylacium anguillae sp. n. (family Anisakidae), is described based on specimens recovered from the stomach and intestine of the giant mottled eel Anguilla marmorata Quoy et Gaimard from the Mngazi River, South Africa, collected in March–April 2011. It is characterized mainly by poorly developed lateral alae, a very short intestinal caecum and a long ventricular appendix, spicules 1.11–2.14 mm long (representing 5.2–5.8 % of body length), number of caudal papillae (19–21 pairs of preanals, 2 adanals and 5 postanals), presence of a median precloacal papilla (= ventromedian organ), tail tips of both sexes covered by minute spines, and by the shape and structure of lips. This is the first nominal species of Hysterothylacium described from an African freshwater fish and the second species of this genus reported from freshwater eels of the family Anguillidae. The following Indian congeneric species are considered species inquirendae: Hysterothalacium aetobathum Lakshmi, 2005, H. carutti Lakshmi, Rao et Shyamasundari, 1993, H. channai Lakshmi, 1995, H. fossillii Lakshmi, 1996, H. japonicum Rajialakshmi, 1996, H. kiranii Lakshmi, 1993, H. longicaecum Lakshmi, Rao et Shyamansundari, 1993, H. narayensis Lakshmi, 1997, H. nellorensis Lakshmi, 1996, H. neocornutum Rajialakshmi, Rao et Shyamasundari, 1992 and H. punctati Lakshmi, 1995. Of them, H. japonicum and H. neocornutum are transferred to Iheringascaris Pereira, 1935 as I. japonica (Rajialakshmi, 1996) comb. n. and I. neocornuta (Rajialakshmi, Rao et Shyamasundari, 1992) comb. n.
A new nematode species, Heliconema monopteri n. sp. (Physalopteridae), is described from the stomach and intestine of the freshwater fish Monopterus cuchia (Hamilton) (Synbranchidae) in Bijnor district, Uttar Pradesh, India. It is mainly characterized by the lengths of spicules (468 – 510 µm and 186 – 225 µm), the postequatorial vulva without elevated lips, the presence of pseudolabial lateroterminal depressions and by the number and arrangement of caudal papillae. This is the first representative of the genus reported from a synbranchiform fish. Another new congeneric species, Heliconema pisodonophidis n. sp. is established based on a re-examination of nematodes previously reported as H. longissimum (Ortlepp, 1922) from Pisodonophis boro (Hamilton) (Ophichthidae) in Thailand; ovoviviparity in this species is a unique feature among all physalopterids. Heliconema hamiltonii Bilqees et Khanum, 1970 is designated as a species dubia and the nematodes previously reported as H. longissimum from Mastacembelus armatus (Lacépède) in India are considered to belong to H. kherai Gupta et Duggal, 1989. A key to species of Heliconema Travassos, 1919 is provided.
M. Bruňanská, H. Fagerholm, F. Moravec and Z. Vasilková
The fine structure of the buccal capsule of the adult female nematode Anguillicoloides crassus (Spirurina) was studied for the first time. Results are based on serial section (longitudinal and transverse) light and transmission electron microscopy. The buccal capsule of A. crassus is a cuticular-lined structure. It can be divided into three main parts: cheilostom, gymnostom and stegostom. The cheilostom is the anterior region of the buccal capsule with the cuticular lining continuous with the body wall cuticle and underlain by epidermal syncytia. The gymnostom is a cuticular region with portions of it very electron dense and underlain by arcade syncytia. A dense circumoral cylinder together with the circumpharyngeal ring represent the prominent characters of the gymnostom. The stegostom is formed by anterior pharyngeal cuticle underlain by muscular radial cells and epithelial marginal cells. The cephalic cuticle of A. crassus makes a direct contact with the pharyngeal cuticle at the base of the circumoral cylinder, within a circumpharyngeal ring containing projections of pharyngeal muscular and marginal cells. The circumoral cylinder, circumpharyngeal ring and pharynx are connected to the body epidermis by junctional complexes. The buccal capsule includes occasionally 3 projections of the pharynx evidently observed in serial cross sections. These ultrastructural characters may provide useful data for comparative, functional as well as evolutionary studies within the Chromadorea.