On the Discovery of the First Tetrapod Burrow from the Pennsylvanian-Age Clifton Formation, Stonehaven, New Brunswick, Canada

Reported trace fossils from the Clifton Formation, New Brunswick, Canada, are limited to a single occurrence of a temnospondyl trackway and invertebrate trackways identified in the Pennsylvanian continental strata. Our study builds on this with a description of a horizontal burrow interpreted to have been constructed by a fossorial tetrapod. Historically, limited focus has been placed on tetrapod burrow activity and its ichnotaxonomy, so our findings also have broader implications. We report on the first horizontal burrow collected from the Clifton Formation near the township of Stonehaven, with unique features that include transversely oriented angular mudstone intraclasts without a meniscate backfill. We propose a new ichnotaxon, Thrasmaichnus hindsi igen. et isp. nov., and interpret the trace as having been made by a fossorial tetrapod. Thrasmaichnus hindsi is the first described Pennsylvanian-age tetrapod burrow, whereas Pennsylvanian-age fossorial tetrapods are currently only known from body fossils.