Postcranial evolution of the insular lineage of Nesiotites Bate, 1944 (Lipotyphla: Nectogalini) from Asoriculus to extinction

Abstract The Balearic shrew Nesiotites represents one of the most remarkable examples of insular evolution among Mediterranean mammals. While most previous studies have focused on its cranial anatomy, little attention has been paid to the postcranial skeleton and its evolutionary transformations through time. In this study, we analyze and compare postcranial elements—including humeri, ulnae, femora, tibiae, and pelves—across the entire temporal range of the Nesiotites lineage in Mallorca, from its earliest representative ( Asoriculus sp., earliest Pliocene, ~5.3 Ma) to the terminal species of the Holocene Nesiotites hidalgo , which survived until after 3,000 cal BC. Drawing on the most complete osteological series available for this lineage, we quantify changes in skeletal proportions and functional morphology to explore patterns of morphological differentiation and life history evolution in an insular context. Comparisons with extant Soricinae and Crocidurinae species provide additional insights into body size trends, limb allometry, and potential locomotor adaptations. We discuss these results in the framework of the “island syndrome”, evaluating the extent to which Nesiotites evolved under relaxed predation, resource limitation, and extended longevity. Our findings highlight the value of postcranial anatomy in reconstructing insular evolutionary trajectories and contribute new data to the paleobiology of extinct shrews.