Longidorid nematodes comprise more than 500 species, and Longidorus and Xiphinema are the most diversified, prevalent, and cosmopolitan genera within plant‐parasitic nematodes. This increases the risk of species misidentification. We conducted an integrative morphometric and genetic study on two longidorid species to elucidate the existence of new cases of cryptic speciation within the genera Longidorus and Xiphinema. Detailed morphological, morphometrical, multivariate, and genetic studies were carried out, and mitochondrial and nuclear haploweb analyses were used to differentiate species within the L. iliturgiensis and X. hispanum complexes. Species delimitation using multivariate and haplonet tools of L. iliturgiensis species complex clearly separated L. tabernensis sp. nov. from L. iliturgiensis and L. indalus, and X. subbaetense sp. nov. from X. hispanum and X. adenohystherum. D2‐D3, partial 18S, and partial coxI regions were used for inferring their phylogenetic relationships with other species in each genus. The present study provides new insights into the diversity of Longidorus and Xiphinema species detected in southern Spain, and new evidence of cryptic speciation in both genera. These results support our hypothesis that the biodiversity of Longidoridae in southern Europe is higher than previously supposed and is still not fully clarified.

Needle nematodes have an economic importance by causing damage to a wide range of natural and cultivated plants not only by directly feeding on root cells, but also by transmitting plant nepoviruses. Two new Longidorus nematodes, Longidorus oakcrassus n. sp. and Longidorus oakgracilis n. sp., are described and illustrated from populations associated with the rhizosphere of Pyrenean oak (Quercus pyrenaica Wild.) in southern Spain. The taxonomic position of both new species within the genus was assigned using an integrative approach. Morphologically, L. oakcrassus n. sp. is characterized by a female with a large and robust body size (9.2-12.2 mm), lip region anteriorly flattened to slightly rounded and almost continuous or slightly offset by a depression with body contour, ca 25.5-32.0 μm wide, amphidial fovea with slightly asymmetrical lobes, stylet composed by an odontostyle moderately long (110.0-133.5 μm) and odontophore weakly developed, pharynx short ending in a terminal pharyngeal bulb with normal arrangement of pharyngeal glands, tail short almost hemispherical shape. Longidorus oakgracilis n. sp. is characterized by having a moderately long and thin female body (5.4-7.9 mm in length), a bluntly-rounded lip region, set off from body contour by a slight depression, amphidial fovea funnel-shaped without lobe, odontostyle moderately long (94.0-106.0 μm), pharyngeal bulb with normal arrangement of pharyngeal glands, short tail, bluntly hemispherical. The presence of males is common in both species. Integrative diagnosis was based on molecular data using D2-D3 expansion domains of the 28S rRNA, 18S rRNA, ITS1 rRNA and partial coxI gene sequences and morphology. Although different gene markers show variations in the phylogenetic relationships, phylogeny indicated that L. oakcrassus n. sp. is phylogenetically related with several species described from the Iberian Peninsula, including L. oakgracilis n. sp., which is clustered with L. cf. olegi, L. lusitanicus and L. silvestris.