Supplementary file 1_Edrathina obditchia, an Ediacaran stem-group ctenophore from the Fermeuse Formation of Newfoundland.docx

Affinities with the c. 10 Ma younger Cambrian stem-ctenophores of the epibenthic Dinomischidae are suggested by comparable morphologies, and supported by our phylogenetic analyses. Edrathina obditchia differs from the Cambrian dinomischids in having a broader basal disc—interpreted as an adaptation for anchoring on Ediacaran microbial matgrounds—and in having offset rather than opposite pinnules. This discovery, along with its likely stem-group ctenophore affinity, suggest an expansion of the stem-ctenophore record into the Ediacaran, supporting hypotheses that invoke a protracted period of metazoan evolution prior to the Cambrian radiation.</p>