AB 2:255-268 (2008)  -  DOI: https://doi.org/10.3354/ab00055

Biology of shallow marine ichnology: a modern perspective

Murray K. Gingras1,*, Shahin E. Dashtgard2, James A. MacEachern2, S. George Pemberton1

1Department of Earth and Atmospheric Sciences, 1-26 Earth Science Building, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
2Department of Earth Sciences, Simon Fraser University, Burnaby V5A 1S6, British Columbia

ABSTRACT: This study considers the construction and functionality of biogenic structures made by marine, vermiform nemerteans, polychaetes and hemichordates; marine crustaceans; motile bivalves; motile echinoderms; and sponges and sea anemones. We report on a range of modern biogenic structures similar to several known ichnogenera. Vermiform animals dominantly occupy vertical burrows that range from simple through helical shafts to Y- and U-shapes. Horizontal traces made by worms range in form, but are dominated by branching and variably sinuous to meandering burrows. Crustaceans primarily excavate open burrow systems that possess a range of architectures that are similar to either Thalassinoides or Psilonichnus. Smaller crustaceans, such as amphipods, mix the sediment. Bivalve traces vary in form, but generally preserve evidence of vertically oriented filter or interface-deposit feeding from a stationary location, rapid vertical escape, or horizontal grazing. Echinoderms dominantly preserve body impressions and motility traces, such as Asteriacites. An important class of biogenic structure, Scolicia and Bichordites, are made by urchins. Finally, sea anemones can generate large, penetrative, conical biogenic structures. Large, open horizontal networks serve as domiciles and deposit-feeding structures for crustaceans, but with worms similar burrow types are used more for passive carnivory and establishing an interface-feeding network. We report that the trace fossil Gyrolithes potentially represents mechanical ramps for shrimp, but is used as a sediment holdfast when made by worms. Finally, Y-shaped burrows are used for filter feeding in shrimp, and interface-deposit feeding in worms. These examples emphasize that inferences of behavior in the rock record are interpretive.

KEY WORDS: Ichnology · Neoichnology · Traces · Crustacea · Vermiforms · Bivalves · Echinoderms · Anemones

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Cite this article as: Gingras MK, Dashtgard SE, MacEachern JA, Pemberton SG (2008) Biology of shallow marine ichnology: a modern perspective. Aquat Biol 2:255-268. https://doi.org/10.3354/ab00055

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