First record case of free-living xanthism in the nurse shark Ginglymostoma cirratum (Bonnaterre, 1788) from Caribbean Sea

Abstract

Xanthism, characterized by yellow pigmentation, is rare in marine species and has not been previously reported in cartilaginous fishes in the Caribbean. Here, we document the first xanthic nurse shark, Ginglymostoma cirratum (Bonnaterre, 1788), recorded in Costa Rican waters. The specimen was captured during a sport fishing trip near Tortuguero National Park, at a depth of 37 m and a water temperature of 31.2 °C. The adult shark, approximately 200 cm in total length, exhibited intense yellow-orange pigmentation and white eyes, indicating a condition known as albino-xanthochromism. This unique finding suggests that xanthism does not hinder survival in this species. Compared to previous reports of abnormal pigmentation in G. cirratum, such as albinism, piebaldism, and hypomelanosis, this is the first scientifically documented case of total xanthism in the species and the first record from the Caribbean Sea. Further research is needed to explore potential genetic or environmental factors influencing this rare pigmentation anomaly in sharks.