A new nematode species (Neoascarophis mariae n. sp.) is described based on specimens collected from the Argentine goatfish Mullus argentinae (Hubbs et Marini) from coastal waters off the state of Rio de Janeiro, Brazil. In the genus, the new species belongs to the group of species with females that have the vulva near the posterior end of the body. Only males of Neoascarophis longispicula Moravec et Klimpel, 2009 are known and can be distinguished from those of the new species by their larger body, developed and somewhat dorsoventrally expanded flat inner part of the pseudolabia, bifurcate deirids and larger spicules (the left one with a rounded tip) with a different length ratio. Other species with females that have the vulva near the equatorial region are N. yarihige Machida, 1976 and N. bathygadi Machida, 1976. Both males and females of N. yarihige are longer than those of the new species and have a shorter vestibule; males have shorter spicules with a different length ratio. Neoascarophis bathygadi is the only member of the genus that shares the presence of a cephalic vesicle with the new species, which, however, is shorter and arises at 40 µm from the anterior end instead from the deirids, as in the new species. Both males and females of N. bathygadi are also longer than those of the new species and have a shorter vestibule; males have a larger left spicule, but shorter right spicule and a different length ratio. Ascarophis upeneichthys Johnston et Mawson, 1945, a parasite of a mullid host, is transferred to Neoascarophis Machida, 1976 and is distinguished from the new species by having a shorter vestibule in females and shorter spicules (left spicule with a pointed tip) with a different length ratio in males.
In most amoeboid cells, the main protein involved in motility is actin. Nematode sperm are an exception, and their amoeboid motility is based on major sperm protein (MSP). We have studied the localization of actin and MSP in spermatids and spermatozoa of Graphidium strigosum (Dujardin, 1845), a species which has elongate male germ cells in which organelles are easily identified. Electrophoreses of G. slrigosum sperm proteins indicate that the main protein band, about 15 kDa in molecular weight, is specifically recognized by an anti-MSP polyclonal antibody developed against MSP of Caenorhabditis elegans (Burke and Ward 1983). Actin is present in small quantities. Immunocytochemical observations reveal that actin and MSP have an identical localization in precise areas of the male germ cells. Spermatids are labelled as dots around a central unlabelled zone, and spermatozoa are labelled only at the level of the anterior cap. Observations in G. strigosum are similar to that previously obtained in Heligmosomoides polygyrus (Mansir and Justine 1996). Co-localization of actin and MSP in the anterior cap of the spermatozoon, the region associated with pseudopod production, does not demonstrate directly that actin is involved in amoeboid movements, but shows that the role of actin in the cytoskeleton of nematode sperm should be re-investigated.
A new nematode species, Guyanema longispiculum sp. n. is described from the abdominal cavity of the freshwater armoured catfish, Loricariichthys hrunneus (Hancock), from two localities in western Venezuela. It differs from all hitherto known members of the genus in having unusually long spicules (0.480-0.609 mm) and from individual species also by other morphological and biometrical features. It is characterized by the presence of eight cephalic papillae arranged in two circlets, localization of deirids anterior to the nerve ring, a conical, undivided tip of the tail in both sexes, four pairs of preanal and six pairs of postanal papillae in the male, and a markedly elevated vulva in the female. A key to species of Guyanema is presented.
Eggs of Huffmanela markgracei sp. n. infected one of three Atlantic sharpnose sharks, Rhizoprionodon terraenovae (Richardson) (Carcharhiniformes: Carcharhinidae) captured by bottom long-line in the northwestern Gulf of Mexico off Padre Island, Texas. Eggs in the skin formed sinuous tracks (1-8 eggs wide; 1-4 eggs deep; 150 eggs/mm2) occupying a swath of the skin 22 cm × 2 cm on the tongue, branchial arches and the dorsal surface of the buccal cavity. Eggs had transverse eggshell ridges (branching and non-branching), had shells that were clear, amber or brown, and measured 90-113 µm (x = 102 ± 4; n = 190) long, 38-54 µm (43 ± 3; 190) wide, 3-5 µm (4 ± 0; 190) in eggshell thickness with protruding polar plugs 8-12 µm (10 ± 1; 190) wide. Apparently fully developed larvae in eggs were 255-335 µm (299 ± 26; 30) long, 8-10 µm (9 ± 1; 30) wide, and in-folded 5-6 (6 ± 0; 30) times. Some of these larvae were emerging from eggs in the skin. The new species differs from congeners by the combination of having a large, spindle-shaped egg, transverse eggshell ridges, an envelope that is smooth, tightly-apposed to the eggshell and surrounds the entire eggshell inclusive of the polar plugs, and a large larva. This is the first report of a species of Huffmanela Moravec, 1987 from a chondrichthyan in the Gulf of Mexico and from a shark not assigned to Carcharhinus.
A new nematode genus and species, Lucionema balatonense gen. et sp. п., is described from the swimbladder of the European pikeperch, Stizostedion lucioperca (L.), from Lake Balaton in Hungary; a new dracunculoid family Lucionematidae fam. n. is established to accommodate it. The hitherto monotypie family Lucionematidae shows affinities with the families Skrja-billanidae and Daniconematidae, differing from them mainly in having simple oesophagus without external oesophageal glands and the vulva situated near the middle of body; from the first family also in the absence of the buccal capsule and the bursa-like caudal alae in the male. The genus Lucionema gen. n. is characterized mainly by the presence of 8 cephalic papillae in two circlets, absence of spicules, presence of the copulatory plate, only 2 pairs of postanal papillae in the male, and by the distal part of the monodelphic uterus forming a posteriorly directed coil. The body length of L. balatonense females is 1074-1782 pm, that of the only available male 770 pm. A key to the families of the Dracunculoidea is presented.
Adult females of Strongyloides robustus Chandler, 1942, a parasite of sciurids in North America, were found in the duodenal mucosa of 30 of 32 red squirrels (Tamiasciurus hudsonicus (Erxleben)) collected in Cape Breton Island, Nova Scotia, Canada. The parasitic female is illustrated and redescribed; characteristics include: body 3.8-8.0 mm long, cephalic extremity with X-shaped mouth and 8 circumoral lobes, ovaries spiralling around intestine, and tail bluntly rounded. Eggs in fresh feces contained tadpole-stage larvae. In fecal cultures, eggs hatched and larvae invariably developed to the filariform infective third stage; i.e. a free-living generation did not occur and is probably absent in S. robustus in Cape Breton and possibly other parts of North America. It is hypothesized that homogonically developing S. robustus might be more fecund or more efficiently transmitted than species of Strongyloides that exhibit both homogonic and heterogonic development. Larvae of S. robustus in fecal cultures, i.e. homogonic larvae, are described in detail. Intestinal walls of second- and third-stage larvae, as well as the lateral chords of young third-stage larvae, contained numerous round bodies, likely nutrient stores. Third-stage larvae were present within 2 days in cultures maintained at 30°C, 4 days at 20°C, and 7 days at 15°C. They lived for at least 33 and 30 days at 15° and 20"C, respectively. Third-stage larvae probably die when their nutrient stores are exhausted.
The genus Maxvachonia Chabaud et Brygoo, 1960 (Ascaridomorpha: Cosmocercidae) is a poorly known group of parasitic nematodes. Species of Maxvachonia are native to Madagascar-Australo-Papuan Region, where they are known to parasitise frogs, snakes and skinks. Unfortunately, most of Maxvachonia species have been inadequately described. In the present study, we report the native species Maxvachonia chabaudi Mawson, 1972 from the intestine of the invasive marine toad Rhinella marina (Linnaeus) in Australia for the first time. We speculate that the marine toads infected with M. chabaudi are likely related to their eating skinks or the similarity in diet/habitat/ecology between the toad and the skinks. The detailed morphology of M. chabaudi was studied using light microscopy and, for the first time, scanning electron microscopy, based on the newly collected specimens. Some characters important for the specific diagnosis of M. chabaudi are reported for the first time, including each lip with distinct inner flanges, the location of vulva varying from anterior to posterior of the oesophageal bulb and the presence of single medio-ventral precloacal papilla. An identification key to the species of Maxvachonia is provided.
The life cycle of Hedruris spinigera Baylis, 1931 (Nematoda: Hedruridae) is determined here with the first formal identification of the parasite's intermediate host: the crustacean amphipod Paracorophium excavatum Thomson. Adult H. spinigera are redescribed from specimens collected from the stomach of fishes, Retropinna retropinna (Richardson) and Aldrichetta forsteri (Valenciennes), from Lake Waihola, New Zealand. Immature adults of the parasite collected from intermediate hosts (P. excavatum) are also described for the first time. The prevalence, abundance and intensity of infection of H. spinigera in several fish species are quantified along with the occurrence of P. excavatum, the parasite's intermediate host, in fish stomach contents. Although H. spinigera's transmission mode (trophic transmission) and fish diet potentially expose all fish species to infection, some level of host specificity must exist as parasite prevalence, abundance and intensity of infection vary greatly between potential definitive host species. We suggest here that the anatomy of the fish digestive tract and especially that of the stomach plays an important role in host suitability for H. spinigera. While P. excavatum is the only intermediate host in Lake Waihola, H. spinigera was found in six different fish species: Aldrichetta forsteri, Galaxias maculatus (Jenyns), Retropinna retropinna, Rhombosolea retiaria Hutton, Perca fluviatilis Linnaeus and Salmo trutta Linnaeus; although typical hedrurid attachment and mating positions were observed only in R. retropinna and A. forsteri. The limited distribution of H. spinigera is most likely due to that of its different host species (intermediate and definitive), all inhabitants of coastal fresh and brackish waters.