Examinations of nematodes collected from some marine fishes off the southwestern coast of Java, Indonesia in 2000 and 2001 revealed the presence of the following six species: ascaridoids Ichthyascaris grandis sp. n. from the intestine of Lophiomus setigerus (Vahl), I. cf. longispicula Li, Liu, Liu et Zhang, 2012 from the intestine of Conger cinereus Rüppel, Ichthyascaris sp. from the body cavity of Lobotes surinamensis (Bloch), and Raphidascaroides halieutaeae Yin, 1983 from the intestine of Halieutaea stellata (Vahl), and philometrids Philometra ivaschkini Parukhin, 1976 from the stomach wall of Trichiurus lepturus Linnaeus and P. psettoditis Moravec, Walter et Yuniar, 2012 from the body cavity (liver) of Psettodes erumei (Bloch et Schneider). Descriptions of these nematodes based on light and scanning electron microscopical studies are provided. The new species I. grandis sp. n. is mainly characterised by large body measurements (males and females up to 41.8 mm and 73.6 mm long, respectively), the length of spicules (0.99-1.05 mm), the tail tip usually without rudimentary spines and by the presence of 44-53 pairs of caudal papillae, eight to twelve of which being postanals. In addition to new data on the morphology of R. halieutaeae and other nematodes recorded, the 11 species of Raphidascaroides Yamaguti, 1941 poorly described from marine fishes in South Asia and reviewed in the monograph of Sood (2017) are considered species inquirendae and incertae sedis.
Based on light and electron microscopical studies, a new nematode parasite, Echinocephalus inserratus sp. n. (Spirurida: Gnathostomatidae), is described from the spiral valve of the broad cowtail stingray Pastinachus ater (Macleay) (Dasyatidae, Myliobatiformes) from off New Caledonia. The new species is morphologically and biometrically most similar to Echinocephalus overstreeti Deardorff et Ko, 1983, differing from it mainly in the absence of serrations on the posterior parts of pseudolabia and on interlabia, and in having a longer gubernaculum (150-299 µm long). Morphologically unidentifiable, mostly encapsulated larvae of Echinocephalus spp. were recorded from the following six species of teleost fishes collected in New Caledonian waters, serving as paratenic hosts: Perciformes: Acanthopagrus berda (Forsskål) (Sparidae) and Nemipterus furcosus (Valenciennes) (Nemipteridae); Tetraodontiformes: Abalistes stellatus (Anonymous), Pseudobalistes fuscus (Bloch et Schneider) (both Balistidae), Lagocephalus sceleratus (Gmelin) (Tetraodontidae) and Aluterus monoceros (Linnaeus) (Monacanthidae). Co-parasitising larvae of Ascarophis sp. and Hysterothylacium sp. were also collected from P. fuscus. All these findings represent new host and geographical records. A key to valid species of Echinocephalus Molin, 1858 is provided.
Recent examinations of some marine fishes from off the southern coast of Iraq revealed the presence of five species of Philometra Costa, 1845 (Nematoda: Philometridae): Philometra arabiensis sp. n. (males and females) from the ovary of the shrimp scad Alepes djedaba (Forsskål) (Carangidae, Carangiformes), Philometra psettoditis Moravec, Walter et Yuniar, 2012 (females) from the body cavity of the Indian halibut Psettodes erumei (Bloch et Schneider) (Psettodidae, Pleuronectiformes), Philometra terapontis Moravec, Gopalakrishnan, Rajkumar, Saravanakumar et Kaliyamoorthy, 2011 (female) from the ovary of the jarbua terapon Terapon jarbua (Forsskål) (Terapontidae, Centrarchiformes), Philometra sp. (females) from the ovary of the Arabian blackspot threadfin Polydactylus mullani (Hora) (Polynemidae, Carangariformes) and Philometra sp. 2 of Moravec et al. (2016a) (females) from the ovary and body cavity of the bartail flathead Platycephalus indicus (Linnaeus) (Platycephalidae, Perciformes). Philometra arabiensis sp. n. is mainly characterised by the length of spicules (198-243 µm) and gubernaculum (75-99 µm), the gubernaculum/spicule length ratio (1 : 2.33-2.79), the structure of the gubernaculum distal portion and the male caudal end, and the body length of males (1.86-2.73 mm). The present findings of P. psettoditis and P. terapontis in fishes of the Arabian Gulf represent new geographical records for these parasites.
Two new species of philometrid nematodes (Philometridae) from needlefishes (Belonidae) in Florida are described based on morphological and genetic characteristics: Philometra aequispiculata sp. n. (males and females) collected from the ovary of Strongylura marina (Walbaum) (type host) and Strongylura notata (Poey), and Philometra notatae sp. n. (females) from the swimbladder of S. notata. Both species are described and illustrated based on light and scanning electron microscopical examinations. Morphologically, P. aequispiculata sp. n. differs from all congeners mainly in the unique structure of the distal tip of the gubernaculum, whereas P. notatae sp. n. is mainly characterised by the presence of eight markedly large cephalic papillae of the outer circle in gravid and subgravid females, the body length of the gravid female (54 mm) and by the absence of caudal projections. Molecular characterisation of the new species was assessed from phylogenetic analysis of mitochondrial cytochrome c oxidase I (COI) and SSU rRNA small-subunit ribosomal RNA (SSU) sequences among closely related philometrids by way of Bayesian inference. Phylogenetic reconstructions based on COI and SSU sequences show each of the new species comprise discrete ancestor-descendent lineages.
Adult specimens of five little-known species of spiruridan nematodes (Spirurida) were collected during occasional examinations of some fishes from the Poonch River in Jammu and Kashmir, India: Procamallanus (Spirocamallanus) bilaspurensis Gupta et Duggal, 1973 in Mastacembelus armatus (Lacépède) (Mastacembelidae, Synbranchiformes), Rhabdochona (Rhabdochona) indica Moravec, Scholz, Ash et Kar, 2010 in Crossocheilus latius (Hamilton) (Cyprinidae, Cypriniformes), Rhabdochona (Rhabdochona) turkestanica (Skryabin, 1917) in Schizothorax richardsonii (Gray) (Cyprinidae, Cypriniformes) and both Rhabdochona (Rhabdochona) hospeti Thapar, 1950 and Rhabdochona (Globochona) cf. chodukini Osmanov, 1957 in Tor putitora (Hamilton) (Cyprinidae, Cypriniformes); besides these, unidentifiable physalopterid larvae were recorded from M. armatus and T. putitora. Their detailed light and electron microscopical studies revealed some taxonomically important, previously not observed features and made possible their redescription. Fourth-stage larvae of P. (S.) bilaspurensis and R. (R.) turkestanica are described for the first time. The latter is resurrected as an independent species. The following are considered to be species inquirendae: a total of nine poorly described species of Rhabdochona Railliet, 1916 from T. putitora in Balochistan, Pakistan, all listed in the monograph of Kakar et al. (2011), plus an additional 15 species of the genus reported from cyprinids and a catfish in the same region (Balochistan) by the same authors. Also three congeneric species from India (R. nemacheili Rautela et Malhotra, 1982, R. putitora Kaur et Khera, 1991 and R. tori Gupta et Srivastava, 1982) and one from Pakistan (R. charsaddiensis Siddiqi et Khattak, 1984) should be considered as species inquirendae due to their poor descriptions. The names of Rhabdochona putitori Anjum, 2013, R. indusi Soofi, Birmani et Dharejo, 2017 and R. sindhicus Soofi, Birmani, Dharejo, Abbasi et Ghachal, 2020 are invalid according to the International Code of Zoological Nomenclature.