Fig 1.
Views of the Skyline Tracksite (TMP L2467) shortly after discovery (A) and following excavation (B).
A) The sediment displacement rim (white arrows) of what turned out to be the first ceratopsid track (C1.1) was all that was visible when the site was first discovered, view looking west. The inner part of the track was already partly exposed at the time the photo was taken. A tyrannosaurid track (black arrow, T1.2) had also been exposed in the foreground. B) View, looking southeast of the Skyline Tracksite following two days of excavation, note C1.1 and T1.2 indicated by white and black arrows, respectively.
Fig 2.
Schematic line drawing of Skyline Tracksite showing relative position and morphology of the mapped traces as of 2024.
A) All mapped traces. B) Traces likely pertaining to ornithischian dinosaurs. C) Traces likely pertaining to theropod dinosaurs. Dashed lines in B indicate possible track series and left/right pairs. Grid scale = 1 m.
Fig 3.
Diagram showing morphometric measurements taken for each vertebrate trace.
Measurements largely follow Therrien and colleagues [12] and Salisbury and colleagues [13]. Image modified from Therrien and colleagues [12].
Fig 4.
Geological context for Skyline Tracksite.
A) Regional geological context for Skyline Tracksite (star) within the Dinosaur Park Formation and the Prosaurolophus maximus-Styracosaurus albertensis dinosaur megaherbivore faunal zone. Grey bar indicates the extent of the stratigraphic column in B. B) Stratigraphic section through Skyline Tracksite in the Dinosaur Park Formation. Trackway located at 8.4 m above base of section.
Fig 5.
Photogrammetrically generated digital elevation model with heat map showing elevation of the Skyline Tracksite (A) and select individual prints (B–D).
A) Model of excavated portion (as of 2024) of main trackway, with heatmap showing absolute elevation. Insets show location of B–D. B) Model of two adjacent traces, C1.1 (left) and T1.2 (right), with relative elevation heatmap. C) Model of C3.1, with relative elevation heatmap. D) Model of A1.1, with relative elevation heatmap. All models in plan view. Elevation legend in A, only pertains to A, as B–D are relative elevation only.
Fig 6.
Examples of the abundant invertebrate trace fossils found in the lower 30 cm of the mudstone overlying the vertebrate trace bearing horizon of the Skyline Tracksite.
A and B) U-shaped marginal tubes of c.f. Rhizocorallium, both without (A) and with (B) spreiten. C) vertical burrows of Skolithos. Scale = 8 cm.
Table 1.
Skyline Tracksite footprint data.
Fig 7.
Individual tracks of Ceratopsipes isp.
A and B) trace C1.1 in photograph (A) and digital model (B). C) Photograph of trace C2.1. D) Photograph of trace C4.1. Scale = 8 cm. Roman numerals indicate interpreted digits.
Fig 8.
Single track of possible ankylosaurid (A1.1).
(A) photograph. (B) digital model. Scale = 10 cm. Roman numerals indicate interpreted digits.
Fig 9.
Individual tracks of tyrannosaurids.
A and B) trace T1.2 in photograph (A) and digital model (B). C) Photograph of trace T1.1. D) Photograph of trace T2.1. Scale = 8 cm. Roman numerals indicate interpreted digits.
Fig 10.
Single potential small theropod footprint (ST1) from the Skyline Tracksite.
Scale = 5 cm.
Fig 11.
Additional trackways found in the Dinosaur Park Formation subsequent to Skyline Tracksite discovery.
A–C) ‘Cathedral Tracksite’ after initial discovery with minimal excavation (A) Sept 9, 2024, and following moderate excavation, Sept 12, 2024 (B), with track interpretation (C) showing a probable ceratopsian track (ce) and a large theropod track (t). Black arrows in A, B indicate the same sediment displacement rim for reference. D) Unexcavated isolated tridactyl print (‘Mueller Tracksite’ Aug 11, 2024, photo credit Andre Mueller). E) Unexcavated potential trackway (‘Lambert Tracksite’, Oct 25, 2024, photo credit Dawson Lambert).