Capillaria appendigera n. sp. (Nematoda: Capillariidae) from the goldbanded jobfish Pristipomoides multidens (Day) (Lutjanidae) and new records of other intestinal capillariids from marine perciform fishes off Australia

A new nematode of the family Capillariidae identified in Cairina moschata (Linnaeus) on Marajó Island in the Brazilian Amazon

Capillaria Zeder, 1800, parasitizes the organs and tissues of several hosts, including the domestic duck Cairina moschata (Linnaeus). This article describes a new species of Capillaria in domestic ducks identified based on morphological studies and molecular analyses of the ribosomal RNA gene. Thirty-eight specimens of C. moschata from the municipality of Soure, Marajó Island, Pará, Brazil. The organs of the birds' digestive tract were analyzed under a stereomicroscope to confirm the parasitic infection, after which the collected nematodes were identified by light microscopy, scanning electron microscopy, and molecular analysis. Capillariids parasitized the intestine and cecum of the examined birds. These parasites had three bacillary bands and a pair of elongated precloacal papillae on the tail. Phylogenetic analysis indicated that the new species formed a sister clade with Capillaria spinulosa (Linstow, 1890), as described in Indonesia and Japan. Based on morphological distinctions and molecular data, Capillaria cairina n. sp. can be considered a new parasite species of C. moschata in the Brazilian Amazon.

Additional morphological characters of the nematode Capillostrongyloides fritschi (Travassos, 1914) Moravec, 1982 (Nematoda: Capillaridae) from Bagrus spp. (Bagridae) inhabiting Damietta Branch of the River Nile, Egypt with a special reference to evaginated cirrus

The catfish Bagrus bajad (Forsskål) and B. docmak (Forsskål) (Siluriformes: Bagridae) are well distributed in the River Nile and have an economic value with good marketing and use in aquaculture. Collected specimens of Capillostrongyloides fritschi (Travassos 1914) were redescribed using a phase-contrast microscope and scanning electron microscope. The most remarkable finding was the unique structure of the evaginated cirrus, being composed of a proximal long tube, a middle spherical bulb packed with mature spermatozoa, and a distal funnel-shaped structure. All regions of the cirrus are provided with longitudinal and transverse muscles and covered with transverse cuticular folds. The mechanism of cirrus emergence was discussed based on available musculature data. Other important findings are the short stylet of the mouth, the two lateral oral lobes, 6-10 buried cephalic papillae and the bacillary bands that lack elevations. Stichosome is formed of 35-44 stichocytes that were differentiated into black and white forms, each containing dense granules and translucent vacuoles. The intestine showed a convoluted part at its anterior region. The vulvar lips are slightly elevated, many mature eggs are cleaved, and their shells are 3-layered. The anus was found in a groove bounded by two unequal lobes.

Description of Pseudocapillaria (Discocapillaria) trilobularis n. sp. (Capillariidae) and redescription of Heliconema alatum (Majumdar, 1965) (Physalopteridae), two nematodes parasitising synbranchiform fishes in India

One new and one already known species of nematodes are described based on specimens collected from synbranchiform fishes of the River Ganga, India, in 2021 and 2022. Pseudocapillaria (Discocapillaria) trilobularis n. sp. (Capillariidae) from the intestine of cuchia Monopterus cuchia (Hamilton) (Synbranchidae) is mainly characterised by the presence of the large ventral postcloacal lobe in the male, the spicule length 351 µm, eggs size 60-69 × 30-36 µm (with protruding polar plugs) and by the body length (male 10.50 mm, females 11.02-12.44 mm). It is the fourth species of this genus recorded from fishes in India. The species Heliconema alatum (Majumdar, 1965) (Physalopteridae) is resurrected. This nematode is redescribed from specimens collected from the intestine of zig-zag eel Mastacembelus armatus (Lacepède) (Mastacembelidae). The examination by SEM revealed some previously not reported morphological features in this nematode species, e.g., the presence of cephalic papillae or a lateroterminal depression and two inner flat dorsoventral teeth on each pseudolabium. Based on these findings, H. monopteri Moravec, Chaudhary & Singh, 2019 is considered a junior synonym of H. alatum.

Huffmanela cf. huffmani (Nematoda: Trichosomoididae) infecting swim bladder, peritoneum, and gonad of variable platyfish, Xiphophorus variatus (Cyprinodontiformes: Poeciliidae) and eastern mosquitofish, Gambusia holbrooki (Poeciliidae) in Florida; taxonomy, phylogenetic analysis, and pathological changes

Variable platyfish, Xiphophorus variatus (Meek, 1904) (Cyprinodontiformes: Poeciliidae) and eastern mosquitofish, Gambusia holbrooki Girard, 1859 (Poeciliidae) from earthen ponds in west central Florida were examined for parasitic infections. At necropsy, we observed myriad nematodes (adults and eggs), which we identified as Huffmanela cf. huffmani, infecting the swim bladder, gonad, and visceral peritoneum. Nucleotide sequences (small subunit ribosomal DNA, 18S) of H. cf. huffmani from variable platyfish and eastern mosquitofish were identical; likewise for newly obtained 18S sequences of Huffmanela huffmani Moravec, 1987 from the swim bladder of red breast sunfish, Lepomis auritus (Linnaeus, 1758) (Centrarchiformes: Centrarchidae) and warmouth, Lepomis gulosus (Cuvier, 1829) from the San Marcos River (type locality for Huffmanela huffmani Moravec, 1987), Texas. The sequences of H. huffmani and H. cf. huffmani differed by 7 (1%) nucleotides. Pathological changes comprised proliferation of the tunica externa of the swim bladder in low-intensity infections in addition to inflammation, proliferation, and tissue necrosis of swim bladder, peritoneum, and gonad in high-intensity infections. The lesion was severe, affecting the cellular constituents of the swim bladder wall and reducing the size of the swim bladder lumen; potentially reducing swim bladder physiological efficiency. The present study is the first record of a freshwater species of Huffmanela Moravec, 1987 from beyond the San Marcos River, first record of a species of Huffmanela from a livebearer, first nucleotide sequences and phylogenetic analysis for Huffmanela, and first evidence that an infection by a species of Huffmanela causes pathological changes that could impact organ function.

Eucoleus contortus (Nematoda: Capillariidae), a parasite of Cairina moschata domestica (Anseriformes: Anatidae) on Marajó Island, Pará State, in Brazilian Amazon

Abstract The family Capillariidae is one of the most important in the superfamily Trichinelloidea, with 27 genera and more than 300 species parasitizing vertebrates. This study considers the morphology, morphometry and prevalence of Eucoleus contortus parasitizing the Muscovy duck Cairina moschata domestica esophagus from Marajó Island, in State of Pará, Brazil. Morphologically the nematodes had a filiform body, with transversely striated cuticle, long esophagus, divided into two parts, one muscular and another consisting of stichocytes, spicule weakly sclerotized, spiny sheath and pseudobursa present in males. Females had a pre-equatorial vulva, barrel-shaped eggs and were bioperculated. In the northern region of Brazil, the Muscovy duck is an abundant bird, and one of the items in the food supply for human communities. The occurrence of E. contortus adds data to the biodiversity of parasites described in Anseriform birds of the Brazilian Amazon, especially those used as source of protein by human communities of Marajó.

Description of Piscicapillaria bursata sp. nov. (Capillariidae) and Redescription of Parascarophis sphyrnae Campana-Rouget, 1955 (Cystidicolidae), Two Nematode Parasites of Hammerhead Sharks (Sphyrna spp.) off Australia

PURPOSE

Data on helminth parasites in hammerhead sharks are scarce and, therefore, new examinations of these hosts are needed to recognize the species composition of their parasites, including nematodes.

METHODS

Helminthological examinations of hammerhead sharks, Sphyrna lewini (Griffith et Smith) (209 specimens) and Sphyrna mokarran (Rüppell) (57 specimens) (Sphyrnidae, Carcharhiniformes), from off the northern coast of Australia revealed one new and one insufficiently known species of intestinal nematode parasites. These were studied with the use of light and scanning electron microscopy.

RESULTS

Both nematode species are described. Piscicapillaria bursata sp. nov. (Capillariidae) from S. mokarran (type host) and S. lewini differs from its congeners mainly in the spicule length (330 µm), body length of gravid females 12.80-21.26 mm and in possessing a subterminal female anus. The specimens of Parascarophis sphyrnae Campana-Rouget, 1955 (Cystidicolidae) (type species of Parascarophis Campana-Rouget, 1955) collected from S. lewini made it possible to redescribe the female and, for the first time, to describe the male; the same species was also found in S. mokarran. Amended diagnosis of Parascarophis is provided. Parascarophis is mainly characterized by the presence of lateral alae, a unique feature within the Cystidicolidae, and by the cephalic structures (presence of a cuticular hood and a pair of anterolateral plate-like structures in the mouth).

CONCLUSIONS

In addition to the discovery of a new nematode species, Pi. bursata sp. nov., the finding of Pa. sphyrnae in Australian waters represents a new geographical record of this parasite outside the Atlantic Ocean. The species of Parascarophis previously described from teleosts, P. bharatii Agrawal, 1965, P. oteroi Arya, 1992 and P. mulloidi Imam, Tawfik et Abdel Hady, 1982, are designated as species inquirendae and incertae sedis. The finding of P. sphyrnae in Australian waters represents a new geographical record of this parasite outside the Atlantic Ocean. Pa. sphyrnae had not been reported previously from beyond the Atlantic Ocean.

Rasheedia n. nom. (Nematoda, Physalopteridae) for Bulbocephalus Rasheed, 1966 (a homonym of Bulbocephalus Watson, 1916), with description of Rasheedia heptacanthi n. sp. and R. novaecaledoniensis n. sp. from perciform fishes off New Caledonia

The nematode genus Bulbocephalus Rasheed, 1966 (Nematoda, Physalopteridae) was found to be a homonym of Bulbocephalus Watson, 1916 (Apicomplexa) and, therefore, a new name, Rasheedia n. nom., is proposed to substitute it. Based on light and scanning electron microscope studies of specimens collected from the digestive tract of perciform fishes off New Caledonia, two new species of Rasheedia are described: R. heptacanthi n. sp. from the Cinnabar goatfish Parupeneus heptacanthus (Mullidae) (type host) and Dentex fourmanoiri (Sparidae), and R. novaecaledoniensis n. sp. from the Indian goatfish Parupeneus indicus (Mullidae). These new species are mainly characterized by the number of anterior protrusible oesophageal lobes (two in R. heptacanthi and four in R. novaecaledoniensis), structure of the oesophagus and the lengths of spicules. An amended diagnosis of Rasheedia and a key to species of this genus are provided. Three previously described congeneric species are transferred to Rasheedia as R. deblocki (Le-Van-Hoa, Pham-Ngoc-Khue & Nguyen-Thi-Lien, 1972) n. comb., R. inglisi (Rasheed, 1966) n. comb. and R. pseudupenei (Vassiliadès & Diaw, 1978) n. comb. Cestocephalus Rasheed, 1966 [genus inquirendum], including C. serratus Rasheed, 1966 and C. petterae (Le-Van-Hoa, Pham-Ngoc-Khue & Nguyen-Thi-Lien, 1972) n. comb., should be considered to be separate from Rasheedia. The names Pseudomazzia Bilqees, Ghazi & Haseeb, 2005 and P. macrolabiata Bilqees, Ghazi & Haseeb, 2005, established for a nematode somewhat resembling Rasheedia spp., should be considered nomina dubia. Rasheedia heptacanthi n. sp. and R. novaecaledoniensis n. sp. are the first representatives of the Physalopteridae recorded from fishes in New Caledonian waters.