Estimating the age of the tataruga (Podocnemis expansa) from femur bones in the Iténez River, Beni, Bolivia

Abstract

The South American river turtle or tataruga (Podocnemis expansa), distributed throughout the Amazon basin, is one of the largest turtle species in the world. It faces several threats that could put its populations at risk. Its distribution, abundance, and diet are well described, but not much is known about its population structure. To understand the growth pattern of this species, we investigated the relationship between carapace length and age in the turtles through a skeletochronological study. Femur samples were obtained from subsistence hunting in the community of Versalles, on the Iténez River in Bolivia. Incisions were made, and an annuli count was performed to determine the age of the turtles. A von Bertalanffy growth curve was then constructed relating age to carapace length. A total of 20 femurs were analyzed, and a higher growth rate was found during the first years of life in female turtles from the study population. Skeletonchronology is shown to be useful for assessing the growth and population structure of the turtles. However, the population range needs to be expanded to obtain more information on juveniles and mature males.