Aberrant Pigmentation in a Schooling Cownose Ray (Rhinoptera bonasus) in Chesapeake Bay, Virginia, USA.

While pigmentation disorders such as albinism have been documented in a range of elasmobranch species, including the American cownose ray (Rhinoptera bonasus), the implications of these rare conditions for behavior, social dynamics, and fitness remain speculative and unverified. Here, we report a case of aberrant pigmentation in a single cownose ray observed schooling among conspecifics in the nearshore waters of Chesapeake Bay, Virginia, USA. The individual displayed pronounced white coloration against a notably dark dorsal surface of both pectoral fins, contrasting sharply with the otherwise uniform brown tones of the surrounding rays. The ray was fully integrated into the school and exhibited no abnormal behavior, suggesting that this pigmentation anomaly did not disrupt social dynamics. This observation augments the small but growing number of reports of pigmentation disorders in R. bonasus, suggesting that important social acceptances required for incorporation into the aggregation were unimpeded by the aberrant pigmentation.