 In a 2012 phylogenetic analysis based on mitochondrial and nuclear DNA , the plain maskray and the <unk> maskray ( N. <unk> ) were found to be the most basal members of Neotrygon . The divergence of the N. annotata lineage was estimated to have occurred ~ 54 Ma . Furthermore , the individuals sequenced in the study sorted into two genetically distinct clades , suggesting that N. annotata is a cryptic species complex . The two <unk> species were estimated to have diverged ~ 4 @.@ 9 Ma ; the <unk> event was likely the splitting of the ancestral population by coastline changes . 
