Two of 98 native littleneck clams, Protothaca staminea Conrad, from Cooper’s Cove, Sooke Basin were infected with an eimeriorin coccidian parasite. Merogonic, gamontogonic and sporogonie development were observed in renal tubular epithelial cells. Sporulation of the oocysts occurred within the host. Mature oocysts were spherical mean 41 pm (range 30-44), and contained about 32 subspherical sporocysts (9 x 10 pm), each of which contained 4 sporozoites. Spherical 19 pm (18-20), cyst-like structures and smaller multinucleate bodies, some of which resembled sporocysts, were also seen.A review of the coccidian parasites of bivalves led to the erection of the new genus, Margolisiella (family Eimeriidae Minchin, 1903) to accommodate M. kabatai sp. n., the parasite in Protothaca staminea described herein. Four previously described monoxenous species (Pseudoklossia patellae Debaisieux, P. chitonis Debaisieux, P. tellinovum Buchanan and P. halintis Friedman, Gardner, Hedrick, Stephenson, Cawthom et Upton) were also transferred to the new genus. The 2 remaining possibly heteroxenous species (P. pelseneeri Léger and P. glomerata Léger et Duboscq) were retained in the genus Pseudoklossia Léger et Duboscq (family Aggregatidae Labbé, 1899).
Two Stomylotrema Looss, 1900 species were found in storks and grebes in Cuba. Five specimens of Stomylotrema bijugum Braun, 1901 were recovered from the roseate spoonbill, Ajaia ajaja (Allen, 1942) (Ciconiiformes) while six Stomylotrema vicarium Braun, 1901 were found in the little blue heron, Egretta (syn. Florida) caerulea (L.) (Ciconiiformes) and the least grebe Podiceps dominicus dominicus (I,.) (Podicipediformes). The taxa represent new host and geographical records. The problem of morphological variation within the genus Stomylotrema is briefly analysed in the discussion.
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.
Four trypanorhynchs, Kotorella pronosoma (Stossich, 1901), Nybelinia cf. bisulcata (Linton, 1889), Nybelinia scoliodoni (Vijayalakshmi, Vijayalakshmi ct Gangadharam, 1996), and Dasyrhynchus pacificus Robinson, 1965 are reported for the first time from the Gulf, which is now known to harbour at least 34 different species. In addition to the range extension for the trypanorhynchs listed above, 21 new host records are reported involving 13 cestode species. Characters of the genus Kotorella Euzet et Radujkovic, 1989 are emended, Nybelinia narinari MaeCallum, 1917 is considered a junior synonym of Kotorella pronosoma (Stossich, 1901), and Heteronybelinia palliata (Linton, 1924) comb. n. is redescribed. The usefulness of the bulb ratio as a means to distinguish different tentaculariid species is discussed, and the importance of shallow water localities for the life cycle of trypanorhynch ccstodes is emphasised.
A new species of Nybelinia Poche, 1926, N. queenslandensis sp. n. (Cestoda: Trypanorhyncha) is described from sharks, Carcharhinus melanopterus (Quoy et Gaimard, 1824) from the coast of northeastern Queensland, Australia. Morphological features of the 46 known species of Nybelinia Poche, 1926 are tabulated and the new species is differentiated from all known taxa that are adequately described on the basis of having a homcomorphous armature, metabasal hooks 20-25 pm long, tentacles 0.07-0.09 mm in diameter, short bulbs (0.38-0.45 mm) and craspedote segments with the testes encircling the female genital complex. The fine structure of the scolex microtriches, frontal and rhynchodeal glands, tentacles and hooks, sheath and retractor muscle is described and compared with that of other trypanorhynchs.
Spirocamallanus rebecae sp. n. is described from freshwater cichlids in some lakes of Southeast Mexico. It has 14 spiral bands in the buccal capsule, similar unequal spicules 503-544 and 281-297 long, 3 precloacal and 6 postcloacal pairs of papillae, vulva situated in the middle part of the body. An updated list of the species of the genus is presented.
The erythrinid fish Hoplias malabaricus in Paraguay harbour two species of proteocephalid cestodes, Proteocephalus regoi sp. n. and Nomimoscolex matogrossensis Rego et Pavanelli, 1990. The former species differs from most South American members of Proteocephalus from fishes by: 1) presence of a small apical organ, 2) distribution of vitellaria, which do not reach to posterior margin of segment and 3) posterior position of vagina. Nomimoscolex matogrossensis is redescribed on the basis of type and recent material, with emphasis given to the morphology of genital organs and scolex, which possesses an apical organ. Both species possess a dense network of osmoregulatory canals in the postacetabular region of both scolex and neck. Proteocephalus regoi sp. n. is the first representative of the subfamily Proteocephalinae parasitizing erythrinid fish.
Results of a study on trypanorhynch ccstodes of fishes from Indonesian coastal waters are presented. A new species, Dasyrhynchus thomasi sp. n., is described, and five species are recorded which all represent new locality records: Tentacularia coryphaenae Bose, 1797; Nyhelinia africana Dollfus, 1960; Nybelinia scoliodoni (Vijayalakshmi, Vijayalakshmi et Gangadharam, 1996); Sphyriocephalus dollfusi Bussieras et Aldrin, 1968; and Otobothrium penetrans Linton, 1907, Their known ranges of distribution are extended to the East-Indian Ocean. Scanning and transmission electron microscopy was used to clarify details of the tentacular armature and surface morphology of T. coryphaenae, D. thomasi and O. penetrans. In T. coryphaenae, hook-like microtriches along the bothridial tegument are embedded in the distal cytoplasm, sometimes showing a split base. The solid tentacular hooks are embedded into a fibrillar, highly ordered tentacular wall. D. thomasi is distinguished by its characteristically shaped bothridia and a triple chainette with winged hooks on the external surface of the tentacle. Tufts of microtrichcs with ciliated sensory receptors arc regularly arranged on the bothridial surface of O. penetrans. They show similarities to sensory receptors reported from other trypanorhynch cestodes. Otobothrium pephrikos Dollfus, 1969 is considered a junior synonym for O. penetrans, and the variability of the scolex within trypanorhynch cestodes is emphasised.