The Review of the Autotomy of Agamid Lizards with Considerations about the Types of Autotomy and Regeneration.

Natalia Borisovna Ananjeva,Dmitry Vyacheslavovich Korost,Dmitry Anatolyevich Gordeev

doi:10.3390/jdb9030032

Abstract

We present a review of the data on the intervertebral autotomy and regeneration of agamid lizards based on an analysis of information obtained over a 35-year period after the publication of thorough reviews (Arnold, 1984, 1988 and Bellairs, Bryant, 1985). It is supplemented by our own studies of 869 specimens of agamid lizards (Sauria, Agamidae) stored in the herpetological collections of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg, Russia) and the Zoological Museum of the Moscow State University (Moscow, Russia), represented by 31 species of 16 genera. The manifestations of the ability for autotomy and regeneration in phylogenetic lineages within the family—Leiolepidinae, Amphibolurinae, Agaminae, Draconinae—are considered. A comparative morphological analysis of the structure of the caudal vertebrae was carried out using the Computer Microtomography Methods (micro-CT) in the following ecomorphological types of agama: (1) with developed abilities to caudal autotomy and regeneration, (2) with the ability to caudal autotomy but without regeneration and (3) without the ability to autotomy. The phenomenon of intervertebral autotomy (urotomy) in snakes is considered too. Possible ways of evolution of the ability to caudal autotomy as a defense strategy against predators are discussed in the phylogenetic context.

Highlights

Published: 16 August 2021Fredericq [1], who described the reflex severance of an appendage, originally introduced the term autotomy
Caudal autotomy has traditionally been considered as a defensive strategy in many lizards and some snakes
An important aspect for understanding the role of autotomy and pseudoautotomy is recording the place of rupture, which depends on a number of factors

Summary

Introduction

Fredericq [1], who described the reflex severance of an appendage, originally introduced the term autotomy. This phenomenon is widespread in the Animalia kingdom and is characteristic, for example, of some mollusks, echinoderms [2], many arthropods [3]. The new tail can measure over 40 cm in length and the segmented vertebrae of the amputated tail are replaced with a calcified rod of cartilage. The frequency of this phenomenon in crocodilians is not exactly known, but it seems to be very low. The caudal vertebrae were replaced by a ventrally located non-segmented endoskeleton and skeletal musculature was absent, instead consisting of fibrous connective tissue composed of type

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Conclusion