Variation in Allometric Shell Growth and Relationship with Sexual Size Dimorphism in Repatriated Indian Star Tortoises (<I>Geochelone elegans</I>) (Reptilia: Testudinidae)

Abstract

This study assesses the rate and pattern of variation of allometric shell growth in Indian star tortoise Geochelone elegans. Morphometric measurements of 83 Indian star tortoises were taken over 6 months. The anal notch measurements correctly classified the sex of the individuals based on the results of multiple regression analysis and chi-square test. Discriminant analysis clustered the growth rates into three age groups. The shell growth across sexes varied with age and morphometric measurements of the shell characters (length in males; width in females). The increase in straight carapace width and plastron length (PL) was significantly different across sexes (females > males and males > females respectively) in 5-7 years age class only. A pronounced increase in PL in males and overall width in females only in the age class of 7-9 years may indicate the influence of sexual selection. The difference in allometric shell growth (in males and females) may thus lead to sexually dimorphic adults.