A Review of Reproductive Cycling in Batoid Dentition Morphology with New Data on Two Dasyatid Stingrays from the Western North Atlantic

A Review of Reproductive Cycling in Batoid Dentition Morphology with New Data on Two Dasyatid Stingrays from the Western North Atlantic

Alvin Sherman Library

Elasmobranchs continuously replace their teeth throughout their lifespan, allowing changes in tooth morphology associated with feeding and reproduction to occur. In many batoid species, males will bite females during pre-copulatory behavior, placing male dentition under selective pressure to meet the demands of both diet and grasping of females. Previous research has documented sexual dimorphism and seasonal dentition changes in several species of batoids, suggesting that this phenomenon is widespread. Much of this research is observation-based, and quantitative studies of dentition are limited, particularly in pelagic species. Pelagic Stingray (Pteroplatytrygon violacea) specimens were previously collected by commercial fishermen, and Bluntnose Stingray (Hypanus say) specimens were collected monthly in collaboration with the Florida Fish and Wildlife Conservation Commission (FWC). Teeth from the functional position of the jaw was extracted, imaged, and analyzed using landmark-based 2D geometric morphometrics. Procrustes-based statistical analyses tested for sexual dimorphism and seasonal variation in tooth shape. Pelagic Stingrays exhibited significant sexual dimorphism (p<0.001), but no significant change in male tooth shape between sample months (October, November, and February; p=0.29). Bluntnose Stingrays displayed significant sexual dimorphism (p<0.001). Males exhibited significant variation in tooth shape between reproductive and non-reproductive seasons (p<0.001), while female tooth shape remained stable. This data can provide cues to reproductive seasonality, feeding ecology, and serves as an important consideration for the identification of batoid species based on dentition.