Limb amputation in lizards as revealed by radiography

Lizards are historically recognized for the ability to voluntarily amputate and regenerate their tails. However, while caudal autotomy has been extensively studied, other types of amputations in lizards remain scientifically underestimated. The present study aimed to assess the extent of knowledge about different types of amputations in lizards and, specifically, to describe anatomically the patterns of limb amputations in Neotropical lizards. We first carried out a systematic bibliographic research regarding the subject, in four academic databases. Moreover, we anatomically described the amputations of seven specimens housed in scientific collections, using external morphological analysis and radiographic techniques. The bibliographic survey revealed that most amputations are related to caudal injuries (67%), while limb amputations accounted for only 24% of the records. Most records mentioned amputations in pelvic limbs (68%), the majority of amputations were provoked by medical-therapeutic procedures (96%), and the main method applied to analyze these lesions were microscopy techniques (80%). Most of the injuries evaluated in museum specimens were also in the hind limbs (86%), mainly involving ruptures in the tibia and fibula and in the femorotibial joint. We also described in detail two rare cases of regeneration of tail-shaped appendages in amputated hind limbs for two species of Neotropical lizards. Our findings revealed that natural amputations in lizard limbs constitute a promising knowledge field for future research, and reinforced the importance of using different assessment methods to investigate body injuries. Thus, we have contributed to the understanding of the causes and consequences of the limb amputation process in lizards.