An enigmatic univalve macromollusc from the lower Cambrian (Series 2, Stage 3) Heatherdale Shale, South Australia

Sarah Jacquet, James B. Jago, Glenn A. Brock

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


Fossils have been reported sporadically throughout the lower Cambrian Heatherdale Shale (Normanville Group), Fleurieu Peninsula, South Australia, but there has been little taxonomic documentation of faunas. Problematic cap -shaped fossils from the lower member of the formation originally attributed to Helcionella are herein formally described as a new genus and species, Tribelopoma amygdala gen. et sp. nov. The asymmetric valves with accretionary growth and probable calcium carbonate composition support a molluscan affinity, and comparisons with other enigmatic cap -shaped taxa suggest a possible helcionelloid affinity. Taphonomic processes related to early diagenesis provide evidence of a rigid shell, prone to brittle fracture during compaction.

Original languageEnglish
Title of host publicationCambro-Ordovician studies VI
EditorsJ. R. Laurie, I. G. Percival, J. B. Jago, J. R. Paterson, G. A. Brock
Place of PublicationCanberra
PublisherAustralasian Paleontologists
Number of pages10
ISBN (Print)9780949466471
Publication statusPublished - 2016

Publication series

NameAustralasian Palaeontological Memoir
PublisherAustralasian Paleontologists
ISSN (Print)2205-8877


  • Mollusca
  • cap-shaped
  • Fleurieu Peninsula
  • Normanville Group
  • Helcionelloida
  • taphonomy

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