A comparison of cuticular ridge patterns and other morphological characters of Mazamastrongylus odocoilei and Mazamastrongylus pursglovei (Nematoda: Trichostrongyloidea) from white-tailed deer Odocoileus virginianus

The synlophes of Mazamastrongylus odocoilei (Dikmans, 1931) and M. pursglovei (Davidson & Prestwood, 1979) from Odocoileus virginianus were described to provide characteristics for their differentiation from related species in domestic and wild ruminants. The synlophes of M. odocoilei and M. pursglovei were identical. Both had single continuous dorsal, ventral and lateral ridges. Other ridges in the lateral fields in the anterior third of the body angled posteriorly ending adjacent to the single lateral ridge. The ridge system in Mazamastrongylus spp. appears to be unique in lacking the continuous subventral and subdorsal ridges present in all previously studied medium stomach worms from domestic ruminants. Only two characters, spicule length and structure, are known to be useful for differentiating males of M. odocoilei and M. pursglovei, and females cannot be differentiated. Evidence that M. odocoilei and M. pursglovei are separate species include: (1) the two species are frequently found together in the same individual host, but each is also found in the absence of the other; (2) no overlap in spicule size or intergrades in shape have been found although numerous populations have been sampled; and (3) the two species have overlapping, but different, geographical ranges in eastern North America. No differences in the synlophe were found between these two species. The importance of this finding is that the absence of differences in the synlophe is not an unequivocal indicator that nematodes are conspecific.