Morphological and molecular characterisation of Pratylenchus araucensis n. sp. (Pratylenchidae), a root-lesion nematode associated with Musa plants in Colombia

Abstract

Abstract Pratylenchus araucensis n. sp., a root-lesion nematode from Musa plants in Colombia, is described and illustrated. The new species is characterised by a combination of the following features: female small to medium sized (376-511 μm) with slender body, lip region with two lip annuli, sometimes an incomplete third annulus, face view characterised by complete fusion of the lip sectors to each other and to oral disc, resulting in a plain and smooth face, anterior surface of the oral disc may be low-conical or flat with rounded edges, short and robust stylet (mean 15.3 μm), short pharyngeal glands (mean 24.2 μm), lateral field with four parallel, non-equidistant lines and middle ridge narrower than outer ones, outer lines with partial areolation and lines converging posterior to the phasmid which is located at mid-tail, vulva located at 78% of total body length and lips well developed, often protruding, posterior uterine sac short (mean 18.1 μm), oval to slightly round spermatheca filled with round sperm, tail clearly conoid in half of population but subcylindrical (25%) or continuous grading from conical to subcylindrical in rest of population, tail terminus variable in shape, mostly conical rounded or rounded; males abundant, spicule 19 μm long. The sequence comparison of the D2D3 rDNA expansion region clearly separates in different clades the new species from P. jaehni, P. loosi and P. coffeae, the only three described species of Pratylenchus that also reproduce by amphimixis and which have lip regions with two lip annuli and a smooth face. Clear autapomorphic characters were present in the D2D3 expansion region of 28S rDNA in all specimens analysed and for both clades of P. araucensis n. sp. and its sister species P. jaehni.