Upper Ordovician Thalassinoides burrows are common in carbonate rocks in the eastern Great Basin. The unidentified bulldozers that caused these burrows behaved much like the Cretaceous-Recent shrimp, Callianassa, as is seen by the similarity of their burrows. Ordovician Thalassinoides formed burrow galleries that reached a depth of up to one meter. Suggestions that organisms were not capable of burrowing deeper than 6 cm in open marine, soft substrata until the end of the Paleozoic must be revised.--Modified journal abstract.

You do not currently have access to this article.