Although cone snails are among the most studied group of gastropods, new species are still regularly described. Here, we focus on Afonsoconus Tucker & Tenorio, 2013, a lineage that includes only two species from the Indo-Pacific Ocean. The analysis of molecular (partial mitochondrial cox1 gene sequences) and morphological (shell and radular tooth) characters revealed that the samples collected by dredging in deep water during a recent expedition carried out in the Mozambique Channel are different from the samples collected in the Pacific Ocean. We thus introduce here a new species, Afonsoconus crosnieri sp. nov., from the SW Indian Ocean including records from the Mozambique Channel, the Comoros and Glorieuses Islands, Madagascar, South Africa and Reunion Island.