Integrative taxonomy of two known dagger nematodes of the genus Xiphinema (Nematoda: Longidoridae) from the Amazon basin in South America, including the first report of X. brasiliense Lordello, 1951 from Colombia and Ecuador

Abstract Three populations of dagger nematodes ( Xiphinema spp.), one recovered from a cassava field ( Manihot esculenta ) in northern Ecuador and two other from a maize field ( Zea mays ) in southern Colombia, were characterized through an integrative approach using morphological data and molecular phylogenetic analysis based on the D2–D3 expansion segments of the 28S and ITS1region of the ribosomal RNA (rRNA) and the partial mitochondrial gene cytochrome c oxidase subunit 1 (COI mtDNA) sequences. Integrating morphological hypotheses with genetic data, the pseudomonodelphic population from Colombia was identified as X. krugi and the monodelphic populations from Colombia and Ecuador were identified as X. brasiliense . Bayesian inference (BI) trees for these three molecular markers allowed establishing phylogenetic relationships highlighting the importance of using phylogenetic data for accurate dagger nematode identification at the species level. To our knowledge, this is the first report of X. brasiliense from Ecuador and Colombia, and the first record of X. krugi in a southerly Colombian region, extending the geographical distribution of these species within South America. In this work, morphological information has been updated to distinguish among Xiphinema species within morphospecies Group 1 and 2. New molecular markers were generated and new knowledge on the genetic diversity, molecular evolution and the geographic distribution of monodelphic Xiphinema species is revealed. This research is one of the first systematic studies for Xiphinema detection in Colombia and Ecuador by an integrative taxonomy.