Correction: The first pterosaur pelvic material from the Dinosaur Park Formation (Campanian) and implications for azhdarchid locomotion (FACETS(2018)2(559–574)Doi: 10.1139/facets-2016-0067)

Abstract

UALVP 56200, originally identified as a partial pelvis of an azhdarchid pterosaur, is a badly broken tyrannosaurid squamosal. Previous conclusions presented about pelvic myology and locomotion in azhdarchids are unsubstantiated and should be disregarded. UALVP 56200 is briefly redescribed here as a squamosal, and provides insights on the extent of cranial pneumaticity in tyrannosaurids Introduction Funston et al. (2017) recently described UALVP 56200, a badly broken, pneumatic bone, as a partial pterosaur pelvis. Shortly after publication it was suggested by T. Carr that the specimen could be a tyrannosaurid squamosal. Further examination confirmed this identification. The specimen shows extensive pneumatic excavation, including enclosed pockets not yet described in tyrannosaurids. Description UALVP 56200 is the medial portion of a left squamosal (Fig. 1). Its anatomical orientation is similar to that described by Funston et al. (2017) except that the lateral surface is actually the medial surface, and vice versa. Anterior and dorsal directions, however, were determined correctly. In articulation, the morphology of a tyrannosaurid squamosal is partly obscured by the parietal, quadrate, and postorbital (Brochu 2003; Currie 2003), which partly accounts for the erroneous identification. The feature interpreted by Funston et al. (2017) as the “acetabulum” is actually the quadrate cotylus (Currie 2003), a deep cavity obscured by the quadrate in articulated specimens. The structure interpreted as the “preacetabular process of the ilium” is the parietal (medial) process, and the so-called “muscle scar” on its anterodorsal surface is the facet for the paroccipital process (Brusatte et al. 2012). The curved edge that was interpreted as the anterior junction of the “sacral rib” and “preacetabular process” is the posteromedial corner of the supratemporal fenestra.(figure presented).