The larval and juvenile development was compared between Lefua echigonia and Lefua sp., both endemic and endangered species in Japan. L. echigonia larvae collected in sunny wetlands were planktonic and swam in the middle to upper layers in lentic waters, whereas L. sp. larvae swam with their abdomen facing toward the substrate along the river bottom in well shaded waters of mountain streams. Larvae and juveniles of both species have a distinct dark band on the lateral side of snout. L. echigonia larvae have melanophores on the dorsal body, gut region, and around the lateral midline, whereas melanophores distribute broadly on the body in L. sp. larvae. Eyes are located more dorsally in larvae of L. sp.: in the ventral view of the head, the eyes of L. echigonia larvae could be seen, but those of L. sp. larvae could not be seen. L. echigonia larvae and juveniles have relatively large eyes and eye diameters were larger than the snout lengths. Lefua sp. larvae and juveniles have relatively small eyes and eye diameters were smaller than the snout lengths. These characters of melanophore distribution, eye size, and eye location are concluded to show adaptation for each habitat.
The external morphology of two bucephalid digenean parasites of Conger conger (Linnaeus) (Congridae, Anguilliformes) caught northwest of the Iberian Peninsula, Prosorhynchus crucibulum (Rudolphi, 1819) Odhner, 1905 and P. aculeatus Odhner, 1905, were studied using scanning electron microscopy (SEM). SEM techniques elucidated new external morphological details, mainly relating to the tegument and protruding organs, such as, in P. crucibulum, a papilla-like structure associated with the pharynx and, in P. aculeatus, the cirrus. The tegument bears scale-like spines, which in both species are arranged quincuncially. The spines of P. crucibulum are wider than long and cover the major part of the body and rhynchus. However, no spines were found in either the central apical depression of the rhynchus or in the middle of the ventral indentation. Also, spines were rarely seen on the tegument around mouth, around the genital aperture or close to the excretory pore. P. aculeatus has spines of a different shape, as wide as they are long and with a rounded margin. They cover the whole body and almost the entire rhynchus, but none were found in the middle of the rhynchus or on its neck region.
Brachylecithum microtesticulatum Timon-David, 1955 (Digenea: Dicrocoeliidae) is recorded for the first time in the Black Sea region. The morphology and variability of the digeneans recovered from Larus argentatus in Bulgaria and the Ukraine are described and compared with the redescription of the species (Bartoli and Mas-Coma 1989). Lyperosomum lari Travassos, 1917 of Smogorzhevskaya (1976) is considered a synonym of B. microtesticulatum.
Human material of an African specimen of Bertiella studeri (Blanchard, 1891 ), a typical intestinal ceslode of monkeys, is described. Mature, postmaturc and gravid proglottides, and eggs, previously inadequately figured, are illustrated and photographed. The description of the species agrees with that provided by Stunkard (1940). A comparative study with other descriptions of the species is made in an attempt to clarify previous findings. The morphological differences reported in various earlier descriptions of the species suggest that B. studeri should be regarded as a “B. studeri species complex”. Improvements are required in the descriptions of new future findings in order to clarify the specific diagnosis of human bertiellosis. Evidence suggests that a generalised diagnosis exclusively based on egg size and geographical distribution is insufficient to differentiate B. studeri and Bertiella mucronata (Meyner, 1895), or additional species may be affecting humans.
The variability of morphological characters was studied in a population of spined loach from Klawój Lake karyologically identified as a pure diploid C. taenia (2n = 48). 24 metric features were used to calculate correlation coefficients and linear regressions to determine the relationships between metric features with total length. As regards 11 meristic features, females had more lateral and predorsal spots than males. Statistically significant differences between males and females were also found in mean values of 15 metric indices. Age variability in the shape of the lamina circularis of males was revealed.
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.
A new highly pathogenic muscle-infecting species of the genus Myxobolus Bütschli, 1882 is described from the Prussian carp, Carassius gibelio (Bloch, 1782) using spore morphology and SSU rDNA sequence data. Phylogenetic analyses elucidated relationship of the newly described Myxobolus lentisuturalis to other Myxobolus species and supported its position of an independent species.
During a survey on the myxosporean fauna of gibel carp Carassius auratus gibelio (Bloch) in China, a species of Myxobolus Bütschli, 1882 that did not conform to any known species was found. The species is characterised by the presence of round to ellipsoidal plasmodia of 2.6-4.0 mm in diameter in the palate of host. Mature spores are obovate in frontal view and lemon-shaped in lateral view, with the following range, mean and standard deviation of dimensions: 10.8-12.8 µm (11.7 ± 0.4 µm) long, 8.2-9.9 µm (8.9 ± 0.4 µm) wide and 6.0-7.5 µm (6.8 ± 0.3 µm) thick. Two polar capsules are pyriform, 4.0-5.5 µm (4.8 ± 0.3 µm) long by 2.9-3.6 µm (3.0 ± 0.2 µm) wide. Polar filaments are coiled, with 5 to 6 turns. A small proportion of spores possesses a short caudal process. Scanning electron microscopy revealed discoid spores with a low sutural ridge and middle bulge. The small subunit ribosomal DNA sequence of this species did not match any available sequences in GenBank. Phylogenetically, this species is sister to M. nielii (Nie et Li, 1973) and M. hearti Chen, 1998 in a Henneguya-Myxobolus clade with robust support. Given the morphological and molecular differences between this species and other Myxobolus species, we propose the name Myxobolus oralis sp. n. for this parasite from gibel carp.
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.
Based on molecular markers (COII and ITS1-ITS2) and morphological data, we describe three new Neotropical species of Gyrodactylus von Nordmann, 1832 from Scleromystax barbatus (Quoy et Gaimard) and Scleromystax macropterus (Regan) from southern Brazil. The three new species can be distinguished from each other by sequences of both molecular markers and morphology of hooks and anchors. Gyrodactylus bueni sp. n. is characterised by having hook with shaft curved, heel straight, shelf straight, toe pointed, anchor with superficial root slender, elongate and male copulatory organ armed with two rows of spinelets. Gyrodactylus major sp. n. presents hook with shaft, point curved, proximal shaft straight, heel convex, shelf convex, toe concave, anchor with superficial root robust and male copulatory organ armed with two rows of spinelets. Gyrodactylus scleromystaci sp. n. presents hook with shaft, point recurved, heel convex, shelf convex, toe pointed, anchor with superficial root curved and male copulatory organ armed with two rows of spinelets. These species appear to be closely related to other species of Gyrodactylus known from other species of Callichthyidae. These new species, however, differ by the comparative morphology of the haptoral hard structures and molecular data. Comparative analysis of sequences from these species of Gyrodactylus suggests that the COII gene may represent an important marker for the taxonomy of species of Gyrodactylidae and, perhaps, for species of other lineages of Monogenoidea.