New evidence of cryptic speciation in the family Longidoridae (Nematoda: Dorylaimida)

Abstract

Longidorid nematodes comprise more than 500 species, and Longidorus and Xiphinema are the most diversified, abundant and cosmopolitan genera, which 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, morphometric, multivariate and genetic studies were carried out, as well as mitochondrial and nuclear haploweb analyses, to differentiate species within the L. iliturgiensis- and X. hispanum-complexes. Species delimitation using haplonet tools of L. iliturgiensis-species complex clearly separated L. tabernensis sp. nov. from L. iliturgiensis and L. indalus. Similarly, the haploweb analysis of X. subbaetense sp. nov. showed it as a unique and separate species from X. hispanum and X. adenohystherum. D2-D3 expansion domains of 28S rRNA, partial 18S rRNA, and partial coxI region were used for inferring phylogenetic relationships. 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.