"Galeus" was suggested to be the sister group of "Apristurus" in a 2005 phylogenetic study based on mitochondrial and nuclear DNA gene sequences, by Samuel Iglésias and colleagues.The affinity between "Galeus" and "Apristurus" was also upheld, albeit weakly, in a 2006 phylogenetic analysis based on three mitochondrial DNA genes, by Brett Human and colleagues.