Considering challenging insights from a taxonomic misidentification

Abstract

In a valuable and progressive contribution towards the knowledge on Caribbean living and fossil rodents (e.g., Turvey et al. 2010, 2012), Mistretta et al. (2021) recently offered the first detailed findings on cricetids from Grenada and Carriacou (Lesser Antillean islands). A new species of the giant Lesser Antillean endemic †Megalomys Trouessart, 1881, was extensively documented along with the oryzomyine Zygodontomys brevicauda (Allen & Chapman 1893) in late Holocene assemblages of Pearls (Grenada) and Sabazan (Carriacou). Our paleontological expertise identifying fragmented remains, enabled us to detect an illustrated material, referred to as Zygodontomys (Mistretta et al. 2021: fig. 7c), which showed differential traits from those of the other materials presented as Zygodontomys. Although it was correctly identified anatomically as a “right maxilla with M2” (Mistretta et al. 2021: fig. 7c, legend) it is neither a Zygodontomys nor a Sigmodontinae but a Muridae. This assertion is based on several features, but primarily on the typical molar pattern composed by separated cusps. In addition, considering the small size of the figured hemimaxillary (with an alveolar molar toothrow of about 4 mm) plus the general morphology of the zygomatic plate and the presence of a marked masseteric scar, it can be confidently referred to the genus Mus Linnaeus, 1758 (Fig. 1).