Nematodirinae (Nematoda : Trichostrongyloidea) chez l'Oreamnos americanus en Alberta, Canada, description du Nematodirus becklundi sp. nov.

Two Nematodirus parasites from Oreamnos americanus from Alberta, Canada, were studied, namely Nematodirus maculosus and Nematodirus becklundi n.sp. Nematodirus becklundi is characterized by the length of the cephalic vesicle being less than double the width, the number of denticles on the corona radiata less than 40, the absence of narrow lateral longitudinal ridges in the anterior part of the body, the absence of a notch between the dorsal and lateral bursal lobes, and the spicules' fused parts (shafts excluded) being shorter than their shafts. Opposite features characterize N. maculosus with which it was probably confounded. In contrast with recent data from the literature, the synlophe of N. maculosus is characterized by a variable number of ridges at the level of the deirids, but always greater than 16.