Revisiting the thermoregulation hypothesis of osteoderms

Subtitle:a study of the crocodilian **Paleosuchus palpebrosus** (Crocodilia: Alligatoridae)

The functional significance of osteoderms-ossified bony structures in the dermis-has been a topic of discussion for many years in biological sciences. Although a protective function has received significant attention in the past, evidence is accumulating that osteoderms might play an important role during physiological activities, specifically thermoregulation. Previous studies have shown that, in crocodilians, the temperature of the skin overlying the osteoderms differs from that of the non-ossified skin during basking. The direction of these differences, however, appears to vary among studies, warranting the re-evaluation of a potential thermoregulatory function. In this study, we explored the thermal benefits of osteoderm expression in dwarf caimans (Paleosuchus palpebrosus). We compared the difference in dorsal and lateral skin temperatures (Delta T) between individuals with fully developed osteoderms and those devoid of any osteoderms, under three different temperature gradients. Our results show that although significant differences in Delta T are present between individuals and between temperature gradients, they do not relate to the expression of osteoderms. The findings of the present study question the thermoregulatory role that osteoderms play in P. palpebrosus, and vertebrates in general, and we put forward a series of alternative (physiological) hypotheses explaining their enigmatic nature.

Publication year:2022

Keywords:A1 Journal article

Accessibility:Closed