New Morphological Characters for Identifying Individual Specimens of Haemonchus spp. (Nematoda: Trichostrongyloidea) and a Key to Species in Ruminants of North America

Redescriptions of Haemonchus mitchelli and Haemonchus okapiae (Nematoda: Trichostrongyloidea) and Description of a Unique Synlophe for the Haemonchinae

“…Statistical treatment of measurements was not done. Previous studies have shown that samples much larger than those available for this study are required (Lichtenfels et al, 1986(Lichtenfels et al, , 1988Jacquiet et al, 1997) to demonstrate significant size differences among species of Haemonchus.…”

“…Measurements were made with a calibrated ocular micrometer. For determining the percentage of the body length covered by the synlophe, the prebursal body in males and the prevulvar body in females were considered to be 100%, and the length of the synlophe is reported as a percentage of that portion of the body (Lichtenfels et al, 1986). Nematode taxa above genus level follow the system of Durette-Desset (1983).…”

“…Terminology for the synlophe follows Lichtenfels et al (2001) and Lichtenfels and Pilitt (2000), except that 1 ridge on each side of the dorsal and ventral fields (previously counted as part of those fields) is now considered to be part of the lateral field. With this modification, the 26-ridge system of H. horaki Lichtenfels et al (2001) has 6 ridges in each lateral field and 7 ridges in each of the dorsal and ventral fields.…”

“…With this modification, the 26-ridge system of H. horaki Lichtenfels et al (2001) has 6 ridges in each lateral field and 7 ridges in each of the dorsal and ventral fields. This change is proposed to correlate the position of the sublateral cords (Lichtenfels and Wergin, 1994) with the separation of lateral fields from dorsal and ventral fields.…”

“…They are among the most economically important parasites of cattle, sheep, and goats, causing significant production losses because of morbidity, mortality, cost of treatment, and suboptimal use of contaminated pastures (Gibbs and Herd, 1986). State of the art descriptions using the most sensitive character for identification of species, i.e., the pattern of surface cuticular ridges, the synlophe (Desset, 1964), is available for only 4 of the 12 species (Lichtenfels et al, 2001) of Haemonchus. A phylogenetic classification of the species is lacking.…”