sentences:  He gave it the name "Trygon longa", in reference to the long tail, and designated a specimen from Acapulco, Mexico and another from Panama as the syntypes.Subsequent authors placed this species in the genus "Dasyatis".A 2001 phylogenetic analysis by Lisa Rosenberger, based on morphological characters, found that the southern stingray ("D. americana") of the western Atlantic is the sister species of the longtail stingray.