The histology and growth rate of Nile crocodile (Crocodylus niloticus) claws

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Authors

Myburgh, Albert
Myburgh, Jan G.
Steyl, Johan Christian Abraham
Downs, Colleen T.
Botha, Hannes
Robinson, Liam
Woodborne, Stephan

Journal Title

Journal ISSN

Volume Title

Publisher

Wiley

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.

Description

DATA AVAILABILITY STATEMENT : The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Keywords

Age estimation, Dietary reconstruction, Growth patterns, Radiocarbon dating, Reptilian claw, Nile crocodile (Crocodylus niloticus), SDG-03: Good health and well-being

Sustainable Development Goals

SDG-03:Good heatlh and well-being

Citation

Myburgh, A., Myburgh, J., Steyl, J., Downs, C. T., Botha, H., Robinson, L., & Woodborne, S. (2023). The histology and growth rate of Nile crocodile (Crocodylus niloticus) claws. Journal of Morphology, 284, e21634. https://DOI.org/10.1002/jmor.21634.