A new filarial nematode, Litomosa vetuni Pikula, Bednarikova & Řehulková n. sp. (Nematoda: Onchocercidae), from the parti-coloured bat Vespertilio murinus in Europe: An integrative species description

A new filarial nematode, Litomosa vetuni n. sp. (Onchocercidae), is described from the parti-coloured bat, Vespertilio murinus , in the Czech Republic. Adult worms were recovered from the abdominal, thoracic and uterine cavities. The new species is the fourth species of Litomosa reported from this host and the first characterised using an integrative approach combining morphology, molecular data ( cox 1 and 12S rDNA) and scanning electron microscopy (SEM). SEM observations provide the first available surface images for a species of Litomosa , showing the position of the amphids and prominent cephalic papillae at the anterior extremity, as well as the arrangement of three caudal lappets in both sexes. Litomosa vetuni n. sp. is distinguished from morphologically similar congeners by the shape and proportions of the segmented buccal capsule, the morphology of the spicules, and the absence of an area rugosa . Both cox 1 and 12S rDNA sequences from the holotype, paratype and their microfilariae formed a well-supported, internally consistent lineage within Litomosa . However, due to the extremely limited availability of reference sequences and the lack of morphological vouchers for other published Litomosa haplotypes, broader phylogenetic placement of the new species within the genus remains unresolved. The study highlights inconsistencies in published morphological descriptions and the scarcity of molecular data for Litomosa spp., emphasising the need for a comprehensive taxonomic revision of bat-associated filarial nematodes using integrative approaches. • A new cavity-dwelling filarial nematode, Litomosa vetuni n. sp., described from Vespertilio murinus in the Czech Republic. • This is the first description of a species of Litomosa using light and scanning electron microscopy. • Phylogenetic analyses based on cox 1 and 12S rDNA sequences confirmed the distinct species status of L. vetuni n. sp. • The taxonomy of bat-associated filarial parasites needs an integrative revision.