Synlophe of Nematodirus odocoilei (Trichostrongyloidea) from deer and caribou in North America with comments on the evolution of Nematodirus spp. among the Cervidae (Artiodactyla)

• Published in: Canadian Journal of Zoology
• Main Authors: Hoberg, Eric P., Fruetel, Michael, Rickard, Lora G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1989
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; caribou; Rangifer tarandus
• Online Access: http://dx.doi.org/10.1139/z89-211; http://www.nrcresearchpress.com/doi/pdf/10.1139/z89-211

The synlophe for specimens of Nematodirus odocoilei from deer (Odocoileus hemionus) and woodland caribou (Rangifer tarandus caribou) is characterized. In the cervical region, at the level of the cervical papillae, there are 36–42 and 38–47 ridges of variable height in males and females, respectively. Sixteen ridges extend to the cephalic expansion. In males, 34–40 ridges occur at midbody, and the synlophe extends posteriad to within 50 μm of the prebursal papillae. In females, 36–42 ridges occur at midbody; the maximum number of ridges occurs posterior to the vulva (50) with a decrease again posteriad. The synlophe is continuous and extends to the caudal extremity of females. Based on concepts of parasite–host biogeography, both host switching and coevolution appear as determinants in the relationships of Nematodirus spp. and cervids. An evaluation of parasite morphology and host–parasite biogeography suggests that in the plesiomorphic condition the synlophe is composed of a high number of ridges as exemplified by Nematodirus spp. from cervids and neotropical camelids.