Abstract
The giant armadillo (Priodontes maximus) is the largest living armadillo and is classified as Vulnerable by the International Union for Conservation of Nature. Little is known about the species biology and especially its reproduction. However, data such as the age at sexual maturity are employed for estimation of a species generation length, which is an important parameter for extinction risk assessment. Thus, the aim of this study is to estimate the age at sexual maturity for male P. maximus in the wild and to predict generation length for this species. During a long-term in situ study, eight male P. maximus were captured for reproductive evaluation considering both morphometric characteristics (e.g. body, penis and testes dimensions), and data on sperm production (assessed by electroejaculation). Based on observations of this study, it is estimated that male P. maximus reach sexual maturity at an age of 6.5–8 years. This is at least 5.5–7 years later than previously published. Consequently, generation length for P. maximus results in 11 years when applying standard formula including age at sexual maturity in males and an estimate of age at last reproduction of 20 years. However, the generation length is probably underestimated here as sexual maturity in females and age at last reproduction could be later than estimates used. Even these conservative estimates result in noticeable change for the timeframe used in extinction risk assessments for this species as it is 33 instead of 21 years. Thus, results from this study might affect the classification status of P. maximus particularly for regional assessments.
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Acknowledgements
We are grateful to the owners of the Fazenda Baía das Pedras for their hospitality, generous support, and permission to work on their land. This study is part of the Giant Armadillo Conservation Program, which benefited from multiple grants, mostly from Zoos in North America and Europe, listed at www.giantarmadillo.org. This study was performed under License No. 27587 (Chico Mendes Institute for Biodiversity Conservation) that granted permission to capture, immobilize, and manipulate armadillos and collect/store biological samples. We would like to thank two anonymous reviewers for their useful comments that help improve the manuscript. All procedures followed the Guidelines of the American Society of Mammalogists for the use of wild mammals in research (Sikes et al. 2016).
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Luba, C.N., Kluyber, D., Massocato, G.F. et al. Size matters: penis size, sexual maturity and their consequences for giant armadillo conservation planning. Mamm Biol 100, 621–630 (2020). https://doi.org/10.1007/s42991-020-00065-3
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DOI: https://doi.org/10.1007/s42991-020-00065-3