Sex-Biased Dispersal Obscures Species Boundaries in Integrative Species Delimitation Approaches

Standardized nuclear markers advance metazoan taxonomy

“…Similar outcomes of over-splitting have also been reported in previous studies using the multispecies coalescent, even if only a few markers were used (58)(59)(60)(61)(62). The main difficulty to date, particularly in young species, is thus to distinguish population structure from speciation (58,59,62), a problem that seems to be more serious rather than alleviated in datasets with large numbers of loci, because population structure is more clearly resolved with more data (63,64).…”

Excluding spatial sampling bias does not eliminate oversplitting in DNA‐based species delimitation analyses

“…This particularly proved to be true in presence of incomplete lineage sorting and hybridization and if geographic bias is not excluded (match ratio <0.5; Dalstein et al, 2019). Extreme oversplitting has been reported for both mtDNA and nDNA, when sex-biased dispersal occurs, which also limits general dispersal (Eberle et al, 2019).…”

Is it time to describe new species without diagnoses?—A comment on Sharkey et al. (2021)

“…Its inaccuracy is due to widely distributed mitochondrial paraphyly of species, which increases with geographical upscaling and more extensive sampling of the analyzed data (Bergsten et al 2012), common sex-biased dispersal and thus biased patterns of COI divergence as well as ancestral polymorphism leading to false "cryptic" divergence (e.g., Ahrens et al 2013;Eberle et al 2019). The COI-inferred species number may in such cases exceed the true species number by up to ten times (Eberle et al 2019). This level of inaccuracy is too high to be acceptable for a robust and stable species delimitation and nomenclature.…”