Bat fly-associated Laboulbeniales were discovered in the 1850s, although at that time known as acanthocephalan worms (Kolenati, 1857). By 1932, the year that marks the death of Roland Thaxter who described hundreds of species of Laboulbeniales, five species of Laboulbeniales from bat flies were described. Twenty years later, Merola (1952) described a sixth species, and it took another 65 years for any taxonomic contributions in this system (Haelewaters et al., 2017b). To date, 18 species in four genera are known to parasitize bat flies (Haelewaters et al., 2021a; Liu et al., 2020; Van Caenegem et al., 2023; W. Van Caenegem and D. Haelewaters, unpublished data): four species of Arthrorhynchus , two species of Dimeromyces, ten species of Gloeandromyces, and two species of Nycteromyces (Fig. 8). In addition, Haelewaters et al . (2020) revealed that Arthrorhynchus eucampsipodae is a complex of at least two species segregated by host genus. Given that A. eucampsipodae has been reported on flies in four genera (de Groot et al., 2020), it could very well be a complex of four species, possibly more.