Enhancing knowledge of species diversity in the genus Paratylenchus (Nematoda: Tylenchulidae): three new pin nematode species and additional insights into a known species from Florida, USA

Abstract

This study expands knowledge on diversity of pin nematodes, Paratylenchus spp. in Florida, USA, by providing integrative descriptions of three new species: Paratylenchus gladensis sp. n., Paratylenchus hodgesi sp. n., and Paratylenchus syngonii sp. n. The new taxa were recovered from natural and agricultural ecosystems, including commercial operations for the production of ornamental plants to be exported to national and international markets. Morphological and morphometric analyses were combined with molecular data from the D2-D3 expansion segments of the 28S rRNA, ITS rRNA, and mitochondrial COI genes to delimit species and infer phylogenetic placement. Comparative diagnoses demonstrated clear distinctions from closely related species, while also highlighting intrapopulation variability in Paratylenchus hawaiiensis, which shows lip region polymorphism. This characteristic was confirmed by the results of molecular analyses using DNA sequences of a polymorphic population of this species. These findings underscore both the high diversity and the taxonomic complexity of Paratylenchus in Florida and emphasize the value of integrative approaches for resolving species boundaries within this challenging genus.