Morphological and molecular characterisation of Neothada olearum sp. nov. (Nematoda: Tylenchidae) from Spain.

Abstract

During nematode surveys conducted to investigate the biodiversity of plant-parasitic nematodes in Mediterranean olive groves with different management strategies (organic and conventional), a nematode population of the genus Neothada was detected in southern Spain. Application of integrative taxonomical approaches clearly demonstrated that it is a new species described herein as Neothada olearum sp. nov., also representing the first report of the genus in Spain. The new species is amphimictic, characterised by a short body (563-774 μm); cuticle widely annulated (2.5-3.0 μm); total number of body annuli 214-226; 16 longitudinal ridges giving a tessellate body surface; stylet without distinct basal knobs (9.0-11.0 μm); and tail elongate-conoid, with tip bluntly rounded. The results of molecular analysis of D2-D3 28S rRNA, ITS rRNA, partial 18S rRNA, and cytochrome oxidase c subunit 1 (COI) gene sequences support for the new species status and clearly separated from N. major and other species within Neothada. Phylogenetic analyses of ribosomal and mitochondrial markers of this study suggested that Neothada is a monophyletic genus, clearly separated from Thada.