Prevalence of Autotomy and Tail Regeneration in Teius teyou (Reptilia, Teiidae)
We analyzed the prevalence of tail autotomy and regeneration in Teius teyou with the use of 640 museum specimens. There is a marked difference in the prevalence of tail autotomy between juveniles (5.4%) and adults (23.9%); we found no significant differences in the prevalence between males and females. In contrast with the trends observed in other families, there exists an inverse relationship between the average size and the prevalence of autotomy among teiid species. We suggest that this could be explained by the important role played by the tail in locomotion, courtship, and defense of teiids. Alternatively, being a large species, these teiids may have an enhanced capacity for repelling attacks without losing their tails. Finally, we report a specimen that presented a bifid regenerated tail. Analizamos la prevalencia de la autotomía caudal y regeneración en Teius teyou utilizando 640 especímenes de museo. Hay una notoria diferencia en la prevalencia de la autotomía caudal entre juveniles (5.4%) y adultos (23.9%); no encontramos diferencias significativas en la prevalencia entre machos y hembras. En contraposición con lo observado en otras familias de saurios, hay una relación inversa entre el tamaño medio y la prevalencia de la autotomía entre las especies de teiidos. Sugerimos que esto podría deberse a que la cola de los teiidos juega un papel importante en la locomoción, el cortejo y la defensa. Alternativamente, al tratarse de especies grandes, pueden tener capacidad de repeler ataques sin sacrificar la cola. También encontramos un espécimen con la cola bifurcada.Abstract
Resumen
Length of the complete tail of Teius teyou discriminated in juveniles, females, and males. We found no significant differences among these groups, so we calculated a single regression line. Regression was performed with the use of logarithms to assess the presence of allometry (y = 0.14 × SVL1.14; r2 = 0.96).
Prevalence of autotomy in juveniles (gray bars), females (black bars), and males (white bars), taking into account their SVL. Solid line represents the average observed prevalence by size class, and dashed line represents the modeled prevalence.
Width of the tail base relative to SVL and discriminated by sex of adult specimens.
(A) Frequency of the relative position of breakage points (the position of the nonregenerated breakage point in relation to the theoretical tail). (B) Frequency of the relative position of autotomy scars (the position of scars in regenerated tails in relation to the theoretical tail). Both figures discriminate juveniles (gray), female adults (black), and male adults (white).
Proportion of the regenerated segment relative to the theoretical missing part and the size (SVL) of the specimens. Lower values of regeneration indicate recent autotomy events.
Above left: ventral view of FML 02611 showing a bifurcated tail. Right: Tomography. Bottom: Radiography of the same specimen.
Teius teyou specimen with a regenerated portion of the tail (red arrow) and a proximal tail breakage (green arrow), demonstrating that repeated autotomy is possible.
Prevalence of natural autotomy as a function of species size (i.e., Teiidae and non-Teiidae species). Non-Teiidae data from Van Sluys et al. (2002).
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