A Reassessment of the Taxonomic Validity of Dynamoterror dynastes (Theropoda, Tyrannosauridae)

Abstract

Associated fragmentary materials of tyrannosaurid theropod, Dynamoterror dynastes McDonald et al., 2018, were reported in 2018 from the Upper Cretaceous Menefee Formation of New Mexico. However, two originally proposed autapomorphies (i.e. prefrontonasal and prefrontolacrimal processes separated by a shallow notch; subrectangular caudal postorbital suture separated from the rostral part by a deep groove) for Dynamoterror are present in other tyrannosaurids, and the poorly preserved nature of the holotype frontal makes it uncertain whether these features are even comparable to other tyrannosaurids. Thus, the combination of inadequacy of autapomorphies and the highly fragmentary nature of the holotype means that the taxonomic name should be regarded as a nomen dubium.