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oai:figshare.com:article/33995238 2026-09-25T13:01:17Z category_39 portal_316 item_type_3 month_year_09_2026

Supplementary file 1_Edrathina obditchia, an Ediacaran stem-group ctenophore from the Fermeuse Formation of Newfoundland.docx Heléna Muirhead-Hunt (25110102) Simon Rosse-Guillevic (25110105) Duncan McIlroy (2840594) Ecology Avalon Assemblage Ctenophora Ediacaran paleontology systematics <p>The Ediacaran fossil Edrathina obditchia gen. et sp. nov., is considered herein to be a large soft bodied metazoan with a bauplan that conforms most closely with that of the stem-group ctenophores. It is characterized by a broad holdfast disc and a subconical calyx, from the upper margin of which at least six stiff pinnulate limbs arise. Edrathina differs from the contemporaneous Rangeomorpha in lacking rangeomorph branches. The Ediacaran staurozoan cnidarian Haootia quadriformis is somewhat similar in having a calyx and stem, but the arms are flexible and define a tetraradial symmetry characteristic of the Staurozoa. The material presented herein comes from the Fermeuse Formation at the c. 551 Ma Inner Meadow Lagerstätte close to Upper Island Cove, Newfoundland, and is preserved as a positive moldic epirelief beneath a volcanic ash layer. 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> 2026-09-25T13:01:17Z Dataset Dataset 10.3389/fevo.2026.1882499.s001 https://figshare.com/articles/dataset/Supplementary_file_1_Edrathina_obditchia_an_Ediacaran_stem-group_ctenophore_from_the_Fermeuse_Formation_of_Newfoundland_docx/33995238 CC BY 4.0