Enigmatic Creature #1 from Cambrian Utah (Halkeriid?)
From a Burgess Shale-like Laggerstatt

Description: This fine problematic creature looks something like a Brachiopod, but is most unusual. My best guess is that t is related to a putative Brachipod precursor called a Halkeriid. The Halkeriids have been described as “armored slugs’ having a Brachipod-like shell at each end. Whatever its true identity, it is a most unusual creature!

The House Range of Utah has several formations that exhibit Burgess Shale-like preservation of soft tissues, and yield fossils of creatures closely allied with the Burgess Shale biota. Interestingly, the formations are normally found in alternating biofacies. Some are rich in trilobites lacking soft bodied organisms, while adjacent ones lack trilobites but preserve soft bodied organisms in the form of kerogenized carbon films. Gaines (2004) has studied the taphonomy of House Range soft tissue preservation, hypothesizing a taphonomic pathway much like the Burgess Shale with delayed decay facilitating rapid diagenesis in an anoxic zone lacking benthic bioturbators. While soft bodied organisms are far rarer and generally not so exquisitely preserved as in the Burgess Shale, some scientists believe the House Range biota might be even more diverse. Many fossils found are enigmatic as to their taxonomic placement. Unfortunately, the numerous sites are much understudied, while mining operations are resulting in wholesale destruction of a potentially rich portion of the Cambrian fossil record.

Related: Soft-bodied Cambrian Explosion Biota from Utah

References:

• Briggs D.E.G., and R.A. Robison. 1984. Exceptionally preserved non trilobite arthropods and Anomalocaris from the Middle Cambrian of Utah. University of Kansas Paleontological Contributions, Paper 111:1-24.
• Gaines, Robert R.; Kennedy, Martin J. Droser, Mary L. 2004. A new hypothesis for organic preservation of Burgess Shale taxa in the middle Cambrian Wheeler Formation, House Range, Utah. Palaeo, 220:193-205.
• House Range Fossils: Wheeler Shale, Marjum Formation, and Weeks Formation, The Virtual Fossil Museum (www.fossilmuseum.net).