Large, robust Cruziana from the Middle Triassic of northeastern British Columbia; ethologic, biostratigraphic, and paleobiologic significance

Large (up to 9.5 cm wide) and robust Cruziana ichnofossils are present in the Middle Triassic (Ladinian) Toad and Liard formations in northern British Columbia, Canada. These trace fossils are the first definitive occurrences of large Cruziana from post-Paleozoic marine strata. These traces, assigned to a new ichnospecies (Cruziana seilacheri), are similar in many respects to traces from the Lower Paleozoic, including the Cambrian ichnotaxon Cruziana rusoformis and the Ordovician ichnotaxon Cruziana furcifera. The morphology and orientation of scratchmarks in these traces suggest that they may have been constructed by either stomatopod or decapod crustaceans. The similarity of the Toad-Liard Cruziana to lower Paleozoic forms and their presence in post-Paleozoic marine rocks demonstrate that care should be taken when utilizing these traces as indicators of either Paleozoic deposition or a specific tracemaker.