Systematics has been formally implemented for about 250 years. In the last decades it has suffered great intellectual change, with the embrace of phylogenetic theory and the availability of molecular information. Here we conduct a systematic revision of Bonnetina, a group of tarantulas endemic to Mexico. Species delimitation is mainly conducted from the integration of morphological and molecular information. The mitochondrial cytochrome c oxidase subunit I (COI) marker is used as molecular barcode, and two formal molecular delimitation methods are employed: Hard-Gap barcoding and Poisson Tree Process. In a few cases, we used geographic distribution modelling for predicting the potential distribution of species. We also make a deeper than usual integration of the molecular information in the taxonomy of the group, by providing combined morphological and molecular diagnoses of the species. From our data, we provide a new diagnosis of Bonnetina and recognize the existence of 17 solidly supported species in the genus, 10 of which are newly described. We provide a COI reference alignment to ease future molecular identifications of Bonnetina species. Our work highlights the importance of using several sources of evidence to the species delimitation problem, because any single view is prone to give biased results.