ABSTRACT
With the ready availability of genomic data from nearly any empirical system, molecular species delimitation has grown rapidly in popularity. The general lineage concept and coalescent theory offered a clear path forward to applying genetic data to infer species boundaries and quickly found traction in the taxonomic community. While these developments have proved valuable, there are several outstanding questions regarding best practices in molecular species delimitation. Here, we review practical and theoretical considerations in molecular species delimitation and highlight promising avenues of future research. We highlight computational advances that allow researchers to make inferences about the evolutionary processes that drove speciation using genomic data and emphasise the importance of using molecular data in combination with phenotypic and ecological data when inferring species boundaries. Finally, we discuss barriers to translating species delimited with molecular data into formally described species.
