Lieberman, Bruce S.Kurkewicz, RichardShinogle, Heather E.Kimmig, JulienMacGabhann, Breandán Anraoi2018-11-092018-11-092017-06-06Lieberman BS, Kurkewicz R, Shinogle H, Kimmig J, MacGabhann BA. (2017) Disc-shaped fossils resembling porpitids or eldonids from the early Cambrian (Series 2: Stage 4) of western USA. PeerJ 5:e3312 https://doi.org/10.7717/peerj.3312https://hdl.handle.net/1808/27287The morphology and affinities of newly discovered disc-shaped, soft-bodied fossils from the early Cambrian (Series 2: Stage 4, Dyeran) Carrara Formation are discussed. These specimens show some similarity to the Ordovician Discophyllum Hall, 1847; traditionally this taxon had been treated as a fossil porpitid. However, recently it has instead been referred to as another clade, the eldonids, which includes the enigmatic Eldonia Walcott, 1911 that was originally described from the Cambrian Burgess Shale. The status of various Proterozoic and Phanerozoic taxa previously referred to porpitids and eldonids is also briefly considered. To help ascertain that the specimens were not dubio- or pseudofossils, elemental mapping using energy dispersive X-ray spectroscopy (EDS) was conducted. This, in conjunction with the morphology of the specimens, indicated that the fossils were not hematite, iron sulfide, pyrolusite, or other abiologic mineral precipitates. Instead, their status as biologic structures and thus actual fossils is supported. Enrichment in the element carbon, and also possibly to some extent the elements magnesium and iron, seems to be playing some role in the preservation process.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.https://creativecommons.org/licenses/by/4.0/PorpitidHydrozoaCnidariaCambrianBurgess shale type fossilElemental mappingEldonidArticle10.7717/peerj.3312openAccess