Fig 1.
Location and stratigraphy of the Highlands region in the main Karoo Basin of South Africa.
A. Simplified geological map of the main Karoo Basin (modified from [9]). B. Generalized stratigraphic column of the Drakensberg Group (modified from [10] with dates from [11], p. 758, 762). C. Simplified geological map and cross-section of the Highlands region in the eastern Free State of South Africa (modified from [12]). Figs A, B and C modified and republished from [9, 10, 12] under a CC BY license, with permission from the Council for Geoscience and Geological Society of South Africa, original copyright 2008, 2009 and 1984, respectively.
Fig 2.
Schematic diagram showing the various track and trackway parameters measured.
(A) Measurements taken on individual footprints. (B) Manus and pes trackway widths (MTW, PTW). (C) Trackway measurements. (D) Parameters used to quantify trackway gauge recommended by Romano et al. [71]. See methods text for a full list of abbreviations used.
Fig 3.
Position of the width measurements taken from the pes and manus trackways.
(A) Highlands trackway A. (B) Chewore trackway. Chewore trackway modified and republished from Lingham-Soliar and Broderick [74] under a CC BY license, with permission from Taylor & Francis, original copyright 2000. Triangular arrows point away from the trackway midline.
Fig 4.
Geological context of the Highlands ichnosite.
(A) Geological map of the vicinity of the Highlands ichnosite. (B) View of the interbed units and basalts to the NE and (C) to the SW from the track-bearing surface. Base map in A is a portion of 2828AD topographic map of the Chief Directorate of the National Geospatial Information (South Africa). This base map was republished under a CC BY license, with permission to reproduce under the Government Printer’s Authorization #11806 of 10 December 2018, original copyright 2001.
Fig 5.
Sedimentary features associated with the sandstone interbeds on Highlands.
(A) Horizontally laminated sandstone interbed unit overlying the basalt with a sandstone-filled fissure and a sharp but non-erosional contact. (B) Ropy-surface texture of pahoehoe lava flows preserved as a natural cast on the underside of a massive sandstone bed. These casts of the ropy-basalt surface suggest that the deposition of the sandstone interbeds occurred in non-erosive, and possibly rapid sedimentation events. (C) Casts of fine desiccation cracks and interference ripple marks (in the inset). (D) Casts of coarse desiccation cracks. (E) Large-scale trough cross-bedding in a 40-cm-thick medium-grained sandstone layer. (F) Planar cross-bedding with tangential, moderately inclined foresets in a ~ 120-cm-thick medium- to fine-grained sandstone layer. (G) Side-view of the track-bearing massive sandstone layer and underlying horizontally laminated sandstone bed. (H) Close-up of portion of G. Abbreviations: Sh–horizontally laminated sandstone; Sm–massive sandstone; Sr–ripple marks or ripple cross-laminated sandstone; St–trough cross-bedded sandstone; Sp–planar cross-bedded sandstone; Ds–desiccation cracks.
Fig 6.
Trackways at the Highlands ichnosite.
(A) Orthophotograph of the palaeosurface. (B) Interpretive outline map of the palaeosurface indicating the trackway patterns, invertebrate trails and desiccation cracks. Trackway A–blue; Trackway B–green; Trackway C–purple. Arrows show locomotion directions.
Fig 7.
Details of individual manus-pes sets tracks in trackway A at Highlands.
(A) Photograph of track A5. (B) Interpretive outline of track A5. (C) False-colour depth model of track A5. (D) Contour map of false-colour depth model of track A5. Contour-line intervals not regular. (E) Photograph of track A6. (F) Interpretive outline of track A6. (G) False-colour depth model of track A6. For relative position of tracks A5 and A6 within trackway A, see Fig 6. Depth scale in centimetres. Tridactyl outlines of manus tracks A5 and A6 are clearly seen in outcrop, although not apparent in 3D images, a difference due to lack of relief in the manus tracks.
Fig 8.
Trackway patterns of tridactyl quadrupeds from southern Africa.
(A) Photograph, (B) False-colour depth model. (C) Interpretive outline of Highlands trackway A (holotype). (D) Photograph and interpretive outline of the Chewore trackway (paratype). Depth scale in centimetres. Locomotion direction toward top of the page in both trackways. Chewore trackway modified and republished from Lingham-Soliar and Broderick (2000) under a CC BY license, with permission from Taylor & Francis, original copyright 2000.
Fig 9.
Analysis of the mesaxony of the Highlands tracks A and C as well as other selected Jurassic tridactyl tracks.
(A) Bivariate plot of the footprint length to footprint width ratio (FL/FW) against the anterior angle length to footprint width ratio (ATL/FW). (B) Explanatory sketch of the measurements of AT used in (A). Data are from this study, Ellenberger [54], Lingham-Soliar and Broderick [74], Lockley [79], Dalman and Weems [80] and Abrahams et al. [81]. For raw data on the Highlands and Chewore ichnosites, see S1 Table.
Table 1.
Ichnological measurements of Delatorrichnopodidae trackways.
Fig 10.
Details of track B2 and trackway B at Highlands.
(A) Photograph of track B2. Note that shadow obscures the toe marks (compare to F). (B) False-colour depth model of track B2 (depth map). (C) Contour map of the false-colour model of track B2. (D) Photograph of trackway B. (E) False-colour depth model of trackway B. Possible manus tracks are labelled ?M. Depth scale shown in C is applicable to B as well. For relative position of track B2 within the trackway, see D and E. For relative position of trackway B within the palaeosurface, see Fig 6. Green arrow shows the locomotion direction. Depth scales in centimetres. (F) Photograph of the silicon rubber cast with inferred tiny circular digit marks and arc (see text explaining the tentative nature of these features).
Table 2.
Ichnological measurements of trackways B, D and E at Highlands.
Fig 11.
Comparison of Early Jurassic trackway patterns from southern Africa.
(A) Schematic illustration of Highlands trackway B from the lower Lesotho Formation, Drakensberg Group (south of Bethlehem, South Africa). (B) Eotetrapodiscus cursor from the upper Elliot Formation, Stormberg Group (zone B1, lower Moyeni, Lesotho). Fig B modified and republished from Ellenberger ([54], fig 72) under a CC BY license, with permission from the Geological Society of South Africa, original copyright 1970.
Fig 12.
Details of tracks C1–6 at Highlands.
Each row shows from left to right: photograph; interpretive outline from photograph; false-colour depth model and contour map superimposed on false-colour depth model. Depth scale in millimetres; for clarity, contour-line intervals not regular. Odd numbers (C1, C3, C5) are left footprints, even numbers (C2, C4) are right footprints. C6 belongs to a different trackway, and has clearer discrete digital pad traces compared to C1–5. For relative position of tracks within main the trackway, see Fig 6.
Table 3.
Ichnological measurements of trackway C at Highlands.
Fig 13.
Palaeoenvironmental reconstruction of the Highlands ichnosite at the Pliensbachian–Toarcian boundary.
See text for details. Heterodontosaurid silhouette is courtesy of Viktor Radermacher.