Much of the discussion and doubts about its taxonomy is related to the existence of two ecotypes of bottlenose dolphins in many part of its distribution. The two ecotypes of the common bottlenose dolphin within the western North Atlantic[19] are represented by the shallower water or coastal ecotype and the more offshore ecotype.[19] Their ranges overlap, but they have been shown to be genetically distinct.[19] They are not currently described, however, as separate species or subspecies.