New Cambrian vermiform organisms from Burgess Shale-type deposits of the western United States

We report new occurrences of scalidophorans, enteropneusts, and other soft-bodied taxa in several middle Cambrian (Miaolingian) formations of the western United States. Among these are the first occurrence of the tubicolous priapulid worm Selkirkia Walcott, 1911 from the Ophir Formation of Utah and possibly from the Bright Angel Formation of Arizona (both Glossopleura Assemblage Biozone, Wuliuan). We document additional Selkirkia willoughbyi Conway Morris & Robison, 1986, S. columbia Conway Morris, 1977, and possible S. spencei Resser, 1939, from the Drum Mountains Wheeler fauna (Wheeler Formation of Utah; Bolaspidella Zone, Drumian). Selkirkia spencei occurs in the Spence Shale Member of the Langston Formation of Idaho (Wuliuan), from which we also describe more specimens. The enteropneust tube Margaretia Walcott, 1931 is quite common at some levels of the Wheeler Formation in the Drum Mountains of Utah, and new Margaretia specimens are also illustrated from the Wheeler Formation in the House Range and the Spence Shale in the Wellsville Mountains. The Wheeler Formation in the Drum Mountains also contains a Spartobranchus-like enteropneust, other possible enteropneusts, and additional undetermined worm-like organisms gen. et sp. indet. Several other taxonomically enigmatic organisms, burrows, or coprolites also occur in the Wheeler faunas of the Drum Mountains and House Range. These occurrences hint at greater diversity of scalidophorans and enteropneusts in the Wheeler ecosystems than has been previously documented, and extend the geographic distribution of the scalidophorans to the Ophir and possibly the Bright Angel formations in western Laurentia.

Automated summary

We report new occurrences of scalidophorans, enteropneusts, and other soft-bodied taxa in several middle Cambrian formations of the western United States. These findings expand the geographic distribution of scalidophorans and suggest a greater diversity of scalidophorans and enteropneusts in the Wheeler ecosystems.