Research ArticlePALEONTOLOGY

Late Ediacaran trackways produced by bilaterian animals with paired appendages

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Science Advances  06 Jun 2018:
Vol. 4, no. 6, eaao6691
DOI: 10.1126/sciadv.aao6691
  • Fig. 1 Geological map and stratigraphic column.

    (A) Generalized geological map of the Yangtze Gorges area, showing the distribution of Ediacaran strata and the fossil location at Wuhe (triangle). Inset map shows the location of the Yangtze Platform in South China. (B) Stratigraphic column of the Ediacaran Doushantuo and Dengying formations, showing stratigraphic occurrences of fossils, including the trackways (triangle) reported in this paper. Mbr, Member; Fm, Formation; SSF, small shelly fossil; HMJ, Hamajing Formation. Zircon U-Pb ages from the work of Schmitz (40). Figure produced by S.X. using Adobe Illustrator.

  • Fig. 2 Trackways and burrows excavated in situ from the Shibantan Member.

    (A and B) Epirelief (top bedding surface) and hyporelief (bottom bedding surface), respectively. NIGP-166148. Trackways (TW1 and TW2) and undermat burrows (UB1 to UB3) are labeled. (C) Latex mold of (B), with trackways and burrows marked and labeled. (D) Enlargement of rectangle in (B), showing connection between TW2 and UB3 (marked). All photographs were taken with lighting from upper right. Scale bars, 2 cm. Figure produced by Z.C. and S.X. using Adobe Photoshop.

  • Fig. 3 Trackway TW1 under different lighting directions.

    (A to E) All are epireliefs. At least four sets of tracks [yellow lines in (E)] can be vaguely recognized, each consisting of two opposingly facing series that are at an acute angle to the midline. Discontinuous impressions along the midline and oblique scratches on the right side of the trackway are vaguely recognizable in (C) and (D), which are enlargements of top and bottom rectangles in (B), respectively. These faint structures are marked in green color in (E) to assist interpretation. The oblique scratches are marked by blue arrows in (C) and (D). Orange arrows identify lighting directions. Scale bars, 2 cm (A, B, and E); 1 cm (C and D). Figure produced by Z.C. and S.X. using Adobe Photoshop.

  • Fig. 4 Comparison between Shibantan and Paleozoic trackways.

    (A to C) Epirelief trackway TW2 under different lighting directions. Repeated track groups (yellow lines) and repeated small shallow dimples (red circles) are marked. Labels L1 to L6 denote different imprints or tracks presumably made by different locomotive appendages of the animal. Orange arrows identify lighting directions. (D) Early Devonian trackway Danstairia congesta from the Old Red Sandstone in Scotland. Courtesy of L. Buatois. Scale bars, 2 cm. Figure produced by Z.C. and S.X. using Adobe Photoshop.

  • Fig. 5 Possible trackways associated with trace fossils of the genus Lamonte from the Shibantan Member.

    (A) Positive hyporelief from the same bedding surface where trackways illustrated in Fig. 2 were found. Two species are recognized on the basis of size: L. trevallis (labeled as Lt) is narrower than Lamonte sp. (labeled as Ls). Note that Lamonte sp. consists of possible trackways (arrows; with poorly preserved imprints) transitioning into burrows (arrowheads). NIGP-166149 (catalog number for the entire slab). (B) L. trevallis from a different stratigraphic horizon of the Shibantan Member. Note burrows (arrowheads) and possible tracks (arrows) preserved as positive and negative epireliefs, respectively. Also illustrated in the study of Chen et al. (13). NIGP-154193. Figure produced by Z.C. and S.X. using Adobe Photoshop.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/6/eaao6691/DC1

    Geological setting

    fig. S1. Transmitted light microscopic images of petrographic thin sections.

    fig. S2. Schematic diagram showing expected differences between preservational variants of burrows and trackways.

    References (4150)

  • Supplementary Materials

    This PDF file includes:

    • Geological setting
    • fig. S1. Transmitted light microscopic images of petrographic thin sections.
    • fig. S2. Schematic diagram showing expected differences between preservational variants of burrows and trackways.
    • References (41–50)

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