Gene sequences are provided for the D3 segment of the large subunit rRNA gene in Pratylenchus agilis, P . hexincisus, P . teres, and P . zeae. They were aligned with the closest comparable previously published molecular sequences and evaluated with parsimony, distance and maximum-likelihood methods. Different outgroups and more taxa in this study compared to a previous D3 tree resulted in improved phylogenetic resolution. Congruence of trees with thermal, vulval and lip characters was evaluated. A tropical clade of Pratylenchus with 2 lip annules was seen in all trees. Maximum-Parsimony and Quartet-Puzzling Maximum-Likelihood trees, with ambiguously-alignable positions excluded and Radopholus similis as an outgroup, had topologies congruent with species possessing 2, 3 or 4 lip annules. An updated sequence for Pratylenchus hexincisus indicated it was an outgroup of P . penetrans, P . arlingtoni, P . fallax and P . convallariae . Pratylenchus zeae was related to P . neglectus in a Neighbor-Joining tree, but was equivocal in others. The relatives of P . teres were P . neglectus and Hirschmanniella belli rather than morphometrically similar P . crenatus . The P . agilis sequence is more closely related to the nearly identical sequences of P . pseudocoffeae and P . brachyurus, than to that of P . scribneri, which is a species closely related morphologically.
