Zum Strongylus tetracanthus‐Problem und zur Systematik der Cyathostominea (Nematoda: Strongyloidea)

Abstract

On the Strongylus tetracanthus Problem and the Systematics of the Cyathostominea (Nematoda: Strongyloidea) The original specimens of the much debated cyathostomine Strongylus tetracanthus MEHLIS, 1831, the type species of Cyathostomum MOLIN, 1861, have been recovered in the Zoological Museum, Berlin. These specimens, collected from horses in Germany, could be shown to belong to 10 of the actually known cyathostomine species. Because none of the species hitherto proposed to be the ‘true’ S. tetracanthus is present in this material, the former Cyathostomum catinatum LOOSS, 1900 is decided to represent this species and a lectotype is selected for C. tetracanthum (MEHLIS, 1831) sensu novo. – Furthermore, the cephalic structures of all Central European cyathostomines have been studied comparatively. Basing on the results, a revised classification of the tribe Cyathostominea is given in form of an annotated key to the genera. Coronocyclus n. gen. is erected for Cyathostomum coronatum LOOSS, 1900 and for 3 further species formerly included in Cyathostomum MOLIN (in the sense of LICHTENFELS 1975); the latter genus is redefined. Parapoteriostomum n. gen. is erected for Cyathostoma mettami LEIPER, 1913 (= Cylicodoniophorus mettami) and for 2 further species formerly included in Cylicodontophorus IHLE (in the sense of LICHTENFELS 1975). Petrovinema ERSOV, 1943 is considered a valid genus. In addition, the identity of one genus as well as of three species and one variety with other taxa is pointed out.

The structure of the community of strongyloid nematodes of domestic equids

“…They argued from the pattern of the frequency distribution, derived from pooled data from several species of Equus, that congeners were not a major source of diversity within the community. As Kennedy & Bush (1992) correctly noted, the assessment of the importance of congeners in equids is complicated by the fact that a number of closely related genera exist within the Cyathostominae and that generic compositions are not entirely stable, as is indicated by comparing the taxonomic works of Lichtenfels (1975) and Hartwich (1986).…”

“…Using the results of Bucknell et al (1995) and the taxonomic arrangement of Hartwich (1986), the overall pattern for the Strongylidae is one in which five or six confamilial species constitute the most frequent type of infections. In arguing that congeners or confamilial species were of minor significance in contributing to community richness, Kennedy & Bush (1992) relied in part on frequency distributions in which singletons were the most frequent type of infection.…”

“…Only nematodes present in the large intestine belonging to the superfamily Strongyloidea were used in analyses. Species present, using the nomenclature of Hartwich (1986), their prevalence and mean intensity of infection (sensn Margolis et al, 1982) are presented in table 1. Nematodes previously identified as Cylicocychis brevicapsulatus by Bucknell et al (1995) have now been reidentified as C. ashworthi and a voucher specimen has been deposited in the United States National Museum Parasite Collection (85425).…”

“…The coexistence of numerous nematode species, particularly members of the family Strongylidae, also makes the nematodes of equids of particular interest from the aspect of helminth community ecology (Kennedy & Bush, 1992), although the possibility has been relatively little exploited. This is surprising since the species-level taxonomy of the strongyloid parasites of equids is relatively stable (Lichtenfels, 1975;Hartwich, 1986), a criterion which frequently does not apply to other parasite groups. Information on the life cycles of the parasites concerned and their localization within the large intestine is also available (Ogboume, 1976(Ogboume, , 1978Ogbourne & Duncan, 1977).…”

Phylogenetic analysis of the genus Cylicocyclus (Nematoda: Strongylidae) based on nuclear ribosomal sequence data

“…They are major pathogens of horses causing pica, anaemia, even death, and leading to significant economic losses (Krecek and Guthrie 1999). There are more than 70 species of equine strongylids belonging to 2 subfamilies, the Strongylinae (large strongyles) and the Cyathostominae (small strongyles or cyathostomes) (Lichtenfels 1975;Hartwich 1986;Zhang and K'ung 2002;Lichtenfels et al 2008).…”