Interrelationships of the durophagous stingrays (Batoidea: Myliobatidae)

In the last few years, estimates of the patterns and timing of the evolution of the pelagic, durophagous stingrays (Myliobatidae) have improved through new comparative data from morphology, the fossil record, and DNA sequences. These recent studies are here reviewed and a conservative summary of myliobatid diversification and origins is presented. The interrelationships and morphological evolution of the durophagous stingrays are discussed, including the nature of devil rays as derived myliobatids. An exploration of myliobatid origins includes estimates of the timing of their diversification and an assessment of gymnurids as a possible sister group. The prevailing signal suggests that the most recent common ancestor of extant myliobatids was a Late Cretaceous oscillating swimmer with a pavement-like dentition. The devil ray lineage began the transition to planktivory by at least the Oligocene, with dentition gradually reduced from grinding plates of interlocking elements to long rows of homodont teeth. Finally, the validity of the genera Manta (Bancroft, 1829) and Pteromylaeus (Garman, 1913) are called into question.