Skip to main content
Giant Deep-Sea Protist Produces Bilaterian-like Traces
Current Biology
  • Mikhail V. Matz, University of Texas - Austin
  • Tamara M. Frank, Harbor Branch Oceanographic Institution
  • N. Justin Marshall, University of Queensland - Brisbane
  • Edith A. Widder, Ocean Research and Conservation Association
  • Sonke Johnsen, Duke University
Document Type
Publication Date
One of the strongest paleontological arguments in favor of the origin of bilaterally symmetrical animals (Bilateria) prior to their obvious and explosive appearance in the fossil record in the early Cambrian, 542 million years ago, is the occurrence of trace fossils shaped like elongated sinuous grooves or furrows in the Precambrian [1-5]. Being restricted to the seafloor surface, these traces are relatively rare and of limited diversity, and they do not show any evidence of the use of hard appendages [2, 6]. They are commonly attributed to the activity of the early nonskeletonized bilaterians or, alternatively, large cnidarians such as sea anemones or sea pens. Here we describe macroscopic groove-like traces produced by a living giant protist and show that these traces bear a remarkable resemblance to the Precambrian trace fossils, including those as old as 1.8 billion years. This is the first evidence that organisms other than multicellular animals can produce such traces, and it prompts re-evaluation of the significance of Precambrian trace fossils as evidence of the early diversification of Bilateria. Our observations also render indirect support to the highly controversial interpretation of the enigmatic Ediacaran biota of the late Precambrian as giant protists [7, 8].

©2008 Elsevier Ltd., All rights reserved

Additional Comments

National Oceanic and Atmospheric Administration Office of Ocean Exploration grant #: NA07OAR46000289

Citation Information
Mikhail V. Matz, Tamara M. Frank, N. Justin Marshall, Edith A. Widder, et al.. "Giant Deep-Sea Protist Produces Bilaterian-like Traces" Current Biology Vol. 18 Iss. 23 (2008) p. 1849 - 1854 ISSN: 0960-9822
Available at: