Morphological and molecular characterisation of Xiphinema ifacolum Luc, 1961 (Nematoda: Longidoridae) from Sri Lanka

Abstract

Summary Females and juveniles from a population of Xiphinema ifacolum from Sri Lanka are described based on morphology, morphometrics and molecular analyses. Morphologically, females and juveniles from Sri Lanka are similar to original descriptions and other reports from Brazil, Cameroon, Liberia, and São Tomé and Príncipe. The identity of the species was also confirmed by 18S rRNA gene sequences deposited in NCBI from Brazil (AY297826). Integrative diagnosis was completed with molecular data using D2-D3 expansion segments of 28S rRNA, ITS1 region, partial 18S-rRNA and the partial mitochondrial gene cytochrome c oxidase subunit 1 (coxI). This is the third molecular characterisation for a species of the X. non-americanum Group 4, after X. oleae and X. tica. The use of different ribosomal and mitochondrial markers in this study, particularly, D2-D3, ITS1 and partial coxI, provided a precise and unequivocal tool for the identification of X. ifacolum and contributes to a better knowledge of the diversity within Xiphinema. Morphospecies Group 4 appears to be a paraphyletic group within the X. non-americanum assemblage.