Abstract

The implementation of molecular tools in parasitology has led to the discovery of numerous cryptic species. However, detailed morphological studies are needed to evaluate the cryptic nature of such species, as well as to provide an appropriate and formal description. Recent phylogenetic analyses using mitochondrial and nuclear genes have revealed that the nematode Spauligodon atlanticus, parasite of lizards of the genus Gallotia that are endemic to the Canary Islands, consists of two highly divergent and unrelated lineages, one in the eastern islands and the other in the western ones. This study provides a detailed morphological analysis of the two S. atlanticus lineages characterised genetically, based on body measurements and scanning electron microscopy. This integrative approach revealed phenotypic differences between them, despite their overall similar morphology. As a result, the new species Spauligodon occidentalis sp. nov., from the formerly western lineage, is described. The morphological similarity between the two Spauligodon species may be explained on the basis of evolutionary convergence, since both species parasitize Gallotia lizards. In addition to delimiting the new nematode species, this study highlights the importance of combining genetic and morphological data with taxonomy in order to uncover the nature of cryptic species and decrease taxonomic uncertainty.