Abstract:
The histology and growth of reptilian and crocodilian claws (ungues) have been
extensively studied; however, Nile crocodile (Crocodylus niloticus) claws have not
received adequate attention. Furthermore, age estimations for reptilian claws remain
unexplored, despite Nile crocodile claws being used in long‐term dietary
reconstruction studies, assuming certain age‐related patterns. In this study, we
investigate the histology and growth patterns of Nile crocodile claws, aiming to infer
axes for sampling cornified material for radiocarbon dating and establish age
estimations for crocodilian claws. Our findings reveal that Nile crocodile claws
exhibit growth patterns similar to other reptilians, presenting as modified scutes/
scales with an age profile along the sagittal plane. This profile starts at the basal germ
matrix and progressively expands in thickness and age dorsoventrally towards the
apex or “tip.” Consequently, the oldest corneous material is concentrated at the most
dorsal point of the claw's apex. To validate previous dietary reconstruction
assumptions, we conducted radiocarbon dating on this region of the claw, which
supported the idea that retained corneous material in the claws is typically relatively
young (5–10 years old) due to abrasion. Our study contributes insights into the
histology and growth dynamics of Nile crocodile claws, shedding light on their use in
dietary reconstruction studies and emphasizing the significance of considering agerelated
assumptions in such investigations.
