Enigmatic organisms preserved in early Ordovician macroborings, western Utah, USA

Macroborings in the Lower Ordovician Fillmore Formation, western Utah, USA, occasionally contain fossil remains of enigmatic organisms. In the most complete specimens a common morphology can be observed. The calcified body wall of the animal is vase-shaped, mimicking the shape of the boring itself. An ovoid body leads up to a neck that contains either a single or double cylinder near the aperture of the boring. The incomplete preservation of the specimens is not sufficient to identify the biological affinity of the organism at this time, but a review of potential groups is warranted. While such groups as barnacles, bivalves, mitrates, and a host of worm-like forms are potential boring inhabitants, none fit what is known of the morphology of the specimens from Utah. Regardless, recognition and future identification of these animals will lead to a greater understanding of complex hardground trophic systems during the Ordovician Bioerosion Revolution.