Résumé
The Anomaluromorpha are one of the five suborders of rodents and include three different families: the Pedetidae, Anomaluridae, and Zenkerellidae. As their name suggests, anomaluromorphs —which include scaly-tailed flying squirrels and springhares— are extremely puzzling rodents. They evolved independently over long periods of time and present very disparate cranial morphologies. In order to investigate how their masticatory apparatus was shaped over time, we first described and then compared the anatomy of the masticatory muscles of all extant anomaluromorph genera (n = 4; Pedetes, Anomalurus, Idiurus, and Zenkerella). We used diffusible iodine-based contrast-enhanced computed tomography (diceCT) methods as they offered the opportunity to accurately and non-destructively dissect specimens from historical museum collections and combined it with traditional dissection when possible. Our observations indicate that the infraorbital part of the zygomaticomandibularis muscle shows an orbital division, which is uncommon for rodents. Moreover, the morphology of the masseter profundus muscle of Zenkerella illustrates the importance of the taxa in understanding the progressive reduction of its relative size to the benefit of the zygomaticomandibularis muscle. In conclusion, the study of the masticatory muscle anatomy can provide valuable informations regarding the evolution and relationships of anomaluromorph rodents as well as to infer ancestral muscle morphologies within the group and compare them to the existing fossil record.