An additional example of the ichnogenus Zoophycos in Cambrian strata (Gallatin Formation; Wyoming, USA)

The ichnogenus Zoophycos is relatively rare in Cambrian-age sedimentary rocks, being far more commonly encountered in post-Devonian, and particularly post-Paleozoic, strata. A new occurrence of Zoophycos from the Upper Cambrian Gallatin Formation of the Bighorn Mountains, north-central Wyoming, USA, is reported herein. Material consists of a single specimen preserved within quartz silt representing the upper surface of a graded quartz arenite bed. The burrow is a relatively wide, curved, horizontally oriented lobe with a poorly visible marginal tube but well-developed internal lamellae. Discovery of this specimen contributes to the paleobiogeographic distribution of lower Paleozoic Zoophycos, adds to the literature suggesting that most Cambrian Zoophycos were horizontal and shallow-tier structures, and provides further support to the notion that relatively complex deposit-feeding behavior evolved earlier in the Phanerozoic than had long been recognized. (c) 2020 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved.

Automated summary

This study reports a new occurrence of Zoophycos from the Upper Cambrian Gallatin Formation of the Bighorn Mountains in north-central Wyoming, USA, contributing to the understanding of the paleobiogeographic distribution of lower Paleozoic Zoophycos and supporting the idea that most Cambrian Zoophycos were horizontal and shallow-tier structures.