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PubMed2004

A redescription of Cylicocyclus adersi Boulenger, 1920 (Nematoda: Strongyloidea: Cyathostominae) parasitic in equids.

As part of a revision of the systematics of the Cyathostominea of equids, we determined that the single type-specimen of Cylicocyclus adersi Boulenger, 1920 is missing and a modern description of this rare species parasitic in donkeys Equus asinus L. and zebras E. burchelli (Gray) and E. zebra L. is not available. Systematists at a workshop on the systematics of the Cyathostominea of horses, convened on August 11, 1997 in Sun City, South Africa, listed C. adersi as a species inquirenda . Herein, we provide a redescription of C. adersi and propose a neotype for the species. The distinctive shape of the buccal capsule of C. adersi , with a relatively tiny 'hoop-like thickening' at its base, a relatively small oesophageal funnel with a thick cuticular lining, and a short, but distinct, dorsal gutter readily distinguishes this species from other large species of Cylicocyclus Ihle, 1922.

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PubMed1981

[Peramelistrongylus Mawson, 1960 and Profilarinema n. gen., trichostrongyloid nematodes apparently transitional between the Strongyloidea and the atypical genus Filarinema Mönnig, 1929 (author's transl)].

Peramelistrongylus skedastos Mawson, 1960, type species of the genus Peramelistrongylus Mawson, 1960 is redescribed. Also described is Profilarinema hemsleyi n. gen., n. sp. from Trichosurus vulpecula in Western Australia. The new genus, which is similar to Filarinema, differs from it essentially by the absence of the complex buccal armature which characterizes the latter genus. The genera Batrachostrongylus Yuen, 1963, parasitic in amphibians, Peramelistromgylus, parasitic in perameloid and dasyuroid marsupials, Profilarinema parasitic in phalangerid marsupials and Filarinema Mönnig, 1929, parasitic in macropodid marsupials, seem to us to constitute a homogeneous evolutionary line distinct from the other Australian trichostrongyloids.

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PubMed1986

[Type identity of the swine parasites Globocephalus longemucronatus and G. urosubulatus (Nematoda, Strongyloidea)].

On the basis of a critical analysis of the literature and of our own investigations, it is pointed out that the two hookworm species known from European swine, namely Globocephalus longemucronatus Molin, 1861 and G. urosobulatus (Alessandrini, 1909), are identical. All the differences hitherto used to distinguish these species are shown to be due to incorrect descriptions of the taxonomic characters or to misinterpretations of statements made by former authors. Accordingly, only one species of Globocephalus occurs in Europe, which has to be named G. longemucronatus Molin, 1861, with Crassisoma urosubulatum Alessandrini, 1909 as its junior synonym. A short diagnosis of this species is given.

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PubMedDate not supplied

[Mechanism of distribution of Strongyloidea larvae among ungulate animals at pasture].

The problem of dissimilation of larvae of strongylates of ruminants in pasture biocoenosis is discussed. A new form of their migration in horizontal direction on the basis of negative geotaxis is suggested. As a result of alternation of vertical migration of larvae on the tilting leaves of the grass and their subsequent washing off with rain or dew down on the ground proceeds their distribution on the pasture. The description of corresponding experiments is given.

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PubMed1997

A redescription of Cylicocyclus triramosus (Nematoda: Strongyloidea): a parasite of the zebra, Equus burchelli antiquorum.

Cylicocyclus triramosus, a rare species of Cyathostominae from the southern African Burchell's zebra (Equus burchelli antiquorum) is redescribed, and a neotype is proposed. The external leaf-crown of the species consists of 30 elements and the internal leaf-crown numerous small and clear elements. The buccal capsule is cylindrical, oval in cross section, and approximately 3 times as wide as deep. The thin walls of the buccal capsule taper anteriorly from a large ringlike, hoop-shaped thickening around the posterior margin. The dorsal gutter is nipple-shaped. The mouth collar is notched dorsally and ventrally. The dorsal ray of the copulatory bursa is slightly elongate and distinctly set off from the lateral lobes. The branches of the dorsal ray have auxiliary branches. Appendages of the genital cone consist of 2 separated, large, semilunar plates with finger-shaped processes on the margins. The vulva-to-anus distance is greater than the tail length. The species is most similar to Cylicocyclus radiatus. Cylicocyclus triramosus differs from all similar species in the presence of dorsal and ventral notches in its mouth collar. In addition, C. triramosus also has a distinctive form of male genital cone appendage. Cylicocyclus radiatus differs further from C. triramosus in lacking a dorsal gutter and having a more elongate dorsal ray and a female tail nearly equal in length to the vulva-to-anus distance.

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PubMed1976

Eucyathostomum webbi sp. n. (Strongyloidea: Cloacinidae) from white-tailed deer (Odocoileus virginianus).

The new species is described from white-tailed deer of McIntosh County, Georgia, and Pushmataha County, Oklahoma. Eucyathostomum webbi sp. n. differs from E. longesubulatum (type) in possessing more internal leaf crown elements, unbarbed spiculte tips, variability in the configuration of the dorsal ray of the male bursa, and shorter vagina and ovejectors; from E. copulatum in being much larger and not having males and females permanently united; from E. spinulosum in the origin of the externo-dorsal ray of the male bursa; and from E. dentatum in having more internal leaf crown elements, shorter spicules, a distinct cephalic vesicle, no dorsal gutter, and a pectinated flange posterior to the vulva. Problems in the taxonomy of the genus Eucyathostomum are discussed. Specimens previously identified as E. longesubulatum from southeastern white-tailed deer were reexamined and found to be conspecific with E. webbi.

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PubMed1990

Extrusion of the residual body in spermatids of Ancylostoma caninum (Nematoda, Strongyloidea).

Transmission electron microscopy reveals that the spermatocytes of the hookworm Ancylostoma caninum contain an abundance of Golgi complexes, ribosomes, specialized membranous organelles, and long strands of smooth endoplasmic reticulum. These organelles remain abundant until the early spermatid stage of sperm development, when they reach their maximum abundance and maturity and the production of new ones ceases. Golgi complexes, ribosomes, and excess SER, which are not functional after this stage, become segregated and confined to the posterior portion of the spermatid in a polar lobe. Later, the polar lobe together with excess cytoplasmic matrix is bound by a membrane and dissociated from the spermatid as a residual body. The spermatid is then devoid of Golgi complexes and ribosomes. Formation of residual bodies as sperm cells mature may be considered a type of cell excretion.

Ancylostoma↗
PubMed1996

Strongylus asini (Nematoda, Strongyloidea): genetic relationships with other Strongylus species determined by ribosomal DNA.

Genomic DNA was isolated from adult Strongylus asini collected from zebra. The second ribosomal transcribed spacer (ITS-2) was amplified and sequenced using polymerase chain reaction (PCR) based techniques. The DNA sequence was compared with previously published data for 3 related Strongylus species. A PCR-linked restriction fragment length polymorphism method allowed the 4 species to be differentiated unequivocally. The ITS-2 sequence of S. asini was found to be more similar to those of S. edentatus (87.1%) and S. equinus (95.3%) than to that of S vulgaris (73.9%). This result confirms that S. Asini and S vulgaris represent separate species and supports the retention of the 4 species within 1 genus.

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PubMed1999

Molecular separation of Oesophagostomum stephanostomum and Oesophagostomum bifurcum (Nematoda: Strongyloidea) from non-human primates.

The ITS-2 sequences for adult specimens of Oesophagostomum stephanostomum from the common chimpanzee and Oesophagostomum bifurcum from the Mona monkey were determined. For both species, the length and GC content of the ITS-2 sequences were 216 bp and 43%, respectively. While there was no unequivocal sequence difference among individual worms representing each of the two species, five (2.3%) interspecific nucleotide differences were detected. These differences were associated with the presence of unique restriction sites in the ITS-2 sequence of 0. stephanostomum for multiple endonucleases of diagnostic value for the differentiation of the two taxa by restriction analysis. Pairwise comparisons of the ITS-2 sequences of O. stephanostomum and O. bifurcum with published ITS-2 sequences for five different congeners indicated that these species from the subgenus Conoweberia are closely related, in accordance with previous morphological studies.

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