Quantifying the cranial variation of Tschudi’s pygmy rice rat, Oligoryzomys destructor (Tschudi, 1845) (Rodentia: Cricetidae) in Peru using geometric morphometrics: ecomorphology and taxonomic insights
Serrano-Villavicencio J.E.; Vendramel R.L.; Pacheco V. · Zoological Journal of the Linnean Society (2026) · DOI: 10.1093/zoolinnean/zlag047
Resumen
Abstract Tschudi’s pygmy rice rat (Oligoryzomys destructor) is a widely distributed cricetid across the Peruvian Andes and Yungas. Two subspecies, O. d. destructor and O. d. spodiurus, have been proposed, mainly based on morphology and their separation by the Marañón River; however, overall cranial shape variation within the species has not been thoroughly evaluated. To explore the influence of the environment on cranial traits, we analysed 252 adult skulls of O. destructor using 2D geometric morphometrics, considering lateral and ventral skull views, as well as the lateral mandible. Specimens were categorized by geographic, ecoregional, and Marañón Riverbank groups. Populations from the eastern Marañón and the Puna presented larger skulls than those from the western and Yungas regions. Principal component analysis of ventral skull shape indicated some differences between the Centre and South groups and between the Puna and Yungas. ANOVA tests showed that southern populations had larger skulls than those of the northern and central groups. Partial least squares analysis identified altitude as the primary factor driving cranial variation, with higher-altitude populations having bulkier skulls and mandibles, probably due to tougher diets. Our results suggest that cranial variation in O. destructor is a plastic response to local ecological conditions, with altitude acting as the key driver of adaptive cranial morphology. © The Author(s) 2026. Published by Oxford University Press on behalf of The Linnean Society of London. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.
Instituciones: Universidad Nacional Mayor de San Marcos