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Bilaterian Burrows and Grazing Behavior at >585 Million Years Ago

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Science  29 Jun 2012:
Vol. 336, Issue 6089, pp. 1693-1696
DOI: 10.1126/science.1216295

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  1. Fig. 1

    Detailed stratigraphic section of the Tacuarí Formation with labeled trace-fossil horizon. Asterisks on the section indicate detrital zircon sampling sites (fig. S1). The U-Pb concordia diagram displays the LA-MC-ICPMS (narrow ellipses) and SHRIMP analyses of zircon grains from the granite intruding into the trace fossil–bearing strata.

  2. Fig. 2

    Photographs of the Tacuarí trace fossils. (A) Typical bilobate furrow with beaded backfill/meniscae visible (black arrows). (B) Irregular trace fossil showing the collapsed top part of the burrow. (C) Sinuous trail illustrating the typical amplitude and wavelength. (D) Well-developed bilobate furrow with circular indentations (black arrow, inset) and raised burrow margins (white arrow). (E) Bilobate furrow showing departure from and return to the plane of preservation. (F) Later burrow intersecting and following a preexisting burrow. (G) Close-up of bedding plane (top view), clearly showing the bilobate furrow that is preserved in many of the burrows. (H) Close-up of the Ediacaran burrow-maker's trail, showing serial indentations along the furrow margin. Scale bars, 1 cm.