Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 17, 1998
Publication Date: N/A
Interpretive Summary: The Protostrongylidae is a group of nematodes that are lung and tissue dwelling parasites, many of which are serious pathogens causing significant pulmonary and neurological disease in wild and domestic ruminants. Control of these parasites is ultimately dependent on an understanding of parasite biology and definition of the relationship between parasites and hosts. Phylogenetic studies of the protostrongyles were undertaken for the first time as the basis for development of predictive classifications for these nematodes. The results of this analysis are significant in diagnosing generic level relationships for these nematodes. Deer are the ancestral hosts, and caprine bovids such as sheep and goats have been secondarily acquired as hosts. This phylogeny provides the context to understand the potential for host- switching by protostrongyles and the environmental and climatological factors that currently determine their distributions. Such data are critical to develop predictions and responses to global change through the transport of animals and through variation in climate.
The phylogeny of nematodes of the family Protostrongylidae (Nematoda: Metastrongyloidea) was reconstructed by cladistic analysis of 28 binary and multistate characters derived from comparative morphology. Analyses were hierarchical and examined: (1) relationships among genera, including 13 ingroup taxa and Metastrongylidae as an outgroup (single tree, 78 steps, CI=0.705); and (2) relationships among genera and species-groups, including 21 ingroup taxa and Metastrongylus apri as an outgroup (single tree, 76 steps, CI=0.582). In the species-level tree, Protostrongylidae was divided into two major clades, one containing the subfamilies Muelleriinae (including the recently described Umingmakstrongylus pallikuukensis), Elaphostrongylinae, and the Varestrongylinae (excluding Pneumocaulus kadenazii). The genus Varestrongylus was paraphyletic as it included Pneumostrongylus calcaratus. The second major clade consisted of a paraphyletic group containing Protostrongylus spp. and Spiculocaulus leuckarti and, basal to this subclade, several other individual protostrongylid lineages. The various subclades generally correspond to the subfamilial divisions of the Protostrongylidae. The Neostrongylinae, however, is not supported as Neostrongylus and Orthosrongylus are not sister groups. Artiodactyles of the family Cervidae are considered basal hosts for protostrongylids; secondary colonization in Caprini, Rupicaprini and among lagomorphs is postulated.