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


Affiliations
1 No. 48, Ayodhya Nagar, Gaulkhed Road, Shegaon, District Buldhana 444 203, India
 

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.

Keywords

Geochelone elegans, Morphometric Differentiation, Sexual Dimorphism, Shell Growth.
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  • Variation in Allometric Shell Growth and Relationship with Sexual Size Dimorphism in Repatriated Indian Star Tortoises (Geochelone elegans) (Reptilia: Testudinidae)

Abstract Views: 421  |  PDF Views: 110

Authors

Abhishek Narayanan
No. 48, Ayodhya Nagar, Gaulkhed Road, Shegaon, District Buldhana 444 203, India

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.

Keywords


Geochelone elegans, Morphometric Differentiation, Sexual Dimorphism, Shell Growth.

References





DOI: https://doi.org/10.18520/cs%2Fv110%2Fi2%2F206-213