Remarkable Cryptic Diversity of Paratylenchus spp. (Nematoda: Tylenchulidae) in Spain

Abstract

[Simple Summary] Paratylenchus spp. are vermiform organisms distributed throughout the world that can parasitize a wide variety of cultivated and wild plants. Some species are considered pathogenic in crops; therefore, correct identification is essential to design management strategies. However, the conserved morphology, similarity of morphometric characters and other factors as co-occurrence of more than one species of Paratylenchus in the same soil sample hinder identification to species level. In consequence, this identification should be carried out jointly with morphological, morphometrical and molecular data. The present research aims to provide morphological and molecular characterization of some Paratylenchus species found in Spain and the description of several new species.

In previous studies, fifteen species of Paratylenchus, commonly known as pin nematodes, have been reported in Spain. These plant-parasitic nematodes are ectoparasites with a wide host range and global distribution. In this research, 27 populations from twelve Paratylenchus species from 18 municipalities in Spain were studied using morphological, morphometrical and molecular data. This integrative taxonomic approach allowed the identification of twelve species, four of them were considered new undescribed species and eight were already known described. The new species described here are P. caravaquenus sp. nov., P. indalus sp. nov., P. pedrami sp. nov. and P. zurgenerus sp. nov. As for the already known described species, five were considered as first reports for the country, specifically P.enigmaticus, P. hamatus, P. holdemani, P. israelensis, and P. veruculatus, while P. baldaccii, P. goodeyi and P. tenuicaudatus had already been recorded in Spain. This study provides detail morphological and molecular data, including the D2-D3 expansion segments of 28S rRNA, ITS rRNA, and partial mitochondrial COI regions for the identification of different Paratylenchus species found in Spain. These results confirm the extraordinary cryptic diversity in Spain and with examples of morphostatic speciation within the genus Paratylenchus.