Probable deinonychosaur tracks from the Upper Cretaceous Wapiti Formation (upper Campanian) of Alberta, Canada

Abstract

Late Cretaceous tracks attributable to deinonychosaurs in North America are rare, with only one occurrence of Menglongipus from Alaska and two possible, but indeterminate, occurrences reported from Mexico. Here we describe the first probable deinonychosaur tracks from Canada: a possible trackway and one isolated track on a single horizon from the Upper Cretaceous Wapiti Formation (upper Campanian) near Grande Prairie in Alberta. The presence of a relatively short digit IV differentiates these from argued dromaeosaurid tracks, suggesting the trackmaker was more likely a troodontid. Other noted characteristics of the Wapiti specimens include a rounded heel margin, the absence of a digit II proximal pad impression, and a broad, elliptical digit III. Monodactyl tracks occur in association with the didactyl tracks, mirroring similar discoveries from the Early Cretaceous Epoch of China, providing additional support for their interpretation as deinonychosaurian traces. Although we refrain from assigning the new Wapiti specimens to any ichnotaxon because of their relatively poor undertrack preservation, this discovery is an important addition to the deinonychosaur track record; it helps to fill a poorly represented geographic and temporal window in their known distribution, and demonstrates the presence of a greater North American deinonychosaur ichnodiversity than has previously been recognized.

Exploring possible ontogenetic trajectories in tyrannosaurids using tracks from the Wapiti Formation (upper Campanian) of Alberta, Canada

“…The Boreal Alberta Dinosaur Project (BADP) revisited the locality (henceforth renamed Tyrants Aisle; Fig. 1) in August 2018, identifying several isolated tyrannosaurid tracks and two possible tyrannosaurid trackways, associated with numerous hadrosaurid and small theropod tracks (Enriquez et al, 2020). Combining the two best preserved examples from Tyrants Aisle, an additional natural cast of a pes track discovered in 2019 from Red Willow Falls, and previously reported examples from nearby localities within the same stratigraphic unit (Fig.…”

The dinosaur tracks of Tyrants Aisle: An Upper Cretaceous ichnofauna from Unit 4 of the Wapiti Formation (upper Campanian), Alberta, Canada

“…Thus, each size class does not necessarily pertain to a distinct trackmaker. In addition to the tridactyl footprints, a collection of small, didactyl tracks from Tyrants Aisle are probably those of troodontid theropods [ 37 ].…”

“…E , interpretive map illustration of trackway area. Images and outlines in A–B and D–E were modified from Fig 3 of Enriquez et al [ 37 ]. Scale bars = 10 cm, unless otherwise indicated, while the physical scale shown in C = 8.2 cm.…”

“…After an additional brief visit by the TMP in 2003, it was noted that the site “requires some salvage efforts and research attention before the prints are lost forever” [ 8 p. 9] owing to its position within the channel of the modern-day Redwillow River and high seasonal discharge. More recently, a collection of theropod footprints identified at the locality—renamed Tyrants Aisle—were studied by Enriquez et al [ 35 – 37 ], although the majority of the tracksite remains undescribed. Therefore, the purpose of this paper is to provide the first detailed description and palaeobiological synthesis of the whole locality, which remains the largest in-situ tracksite known from the Wapiti Formation to date.…”

Taphonomy and taxonomy of a juvenile lambeosaurine (Ornithischia: Hadrosauridae) bonebed from the late Campanian Wapiti Formation of northwestern Alberta, Canada

“…Unlike its more famous southern counterparts, which are interrupted by marine transgressions of the Bearpaw Formation, the Wapiti Formation is a continuous package of terrestrial sediments (Eberth & Getty, 2005;Fanti & Catuneanu, 2009;Eberth & Braman, 2012). Although the Wapiti Formation was originally only for a single ceratopsian site, the Pipestone Creek Bonebed (Currie, Langston & Tanke, 2008b), fieldwork over the past 10-15 years has uncovered abundant vertebrate ichnofossils , articulated skeletons with skin impressions (Bell et al, 2014a;Bell et al, 2014b;Enriquez et al, 2021;Enriquez et al in press), microfossil sites (Fanti & Miyashita, 2009), and macrofossil bonebeds (Tanke, 2004;Currie, Langston & Tanke, 2008b;Fanti, Currie & Burns, 2015) (Fig. 1).…”