Middle Cambrian priapulids and other soft-bodied fossils from Utah and Spain

The fossil priapulid worms Ottoia prolifica, Selkirkia willoughbyi n. sp., Selkirkia spencei, and Selkirkia sp. are illustrated from the Middle Cambrian of Utah. New records of O. profilica from the Spence Shale and Marjum Formation represent notable geographic and stratigraphic extensions of its previously unique occurrence in the Stephen Formation of British Columbia. O. prolifica has a range through much of the Middle Cambrian (?15 Ma), during which time it shows minimal morphological change. New records of S. spencei augment previous finds in the Spence Shale. S. willoughbyi n. sp. occurs in the Marjum Formation and Wheeler Formation. It differs from the type species S. columbia in details of tube size and degree of tapering, although the poorly known soft parts appear to be broadly similar. These occurrences extend significantly the stratigraphie range of Selkirkia, and are augmented by the discovery of Selkirkia sp. in the Wheeler Formation. A unique specimen of the possible annelid worm Palaeoscolex, P. cf. P. ratcliffei, is described from the Middle Cambrian of Spain, thereby extending the geographic range from previously known occurrences in England, Utah, and South Australia. Papillate ornamentation of various species of Palaeoscolex is compared, and the new class Palaeoscolecida is erected. These descriptions of soft-bodied organisms provide further information on the diversity of Cambrian life. The possibility that present information on soft-bodied and lightly skeletized biotas is biased toward deeper water, possibly conservative, forms is discussed. Brief descriptions of possible soft-bodied worms and trace fossils (burrows and questionable coprolites) from Utah are also given.