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Keywords:

  • Conulariids;
  • Paraconularia;
  • scyphozoans;
  • clonal building;
  • conulariid paleobiology;
  • conulariid affinities;
  • Pennsylvanion

Monospecific conulariid clusters have been interpreted as products of gregarious behavior or as clonal colonies, with members of a colony originally inclined at a high angle to the substrate and connected to each other at their apices. However. individuals in all previously documented clusters are preserved parallel, or nearly parallel, to bedding, and their apices are not preserved. We describe a cluster of three Paraconularia crustula (White) (Pennsylvanian of Missouri, USA) in which the individual specimens exhibit an original steeply inclined orientation. The individuals in this cluster converge adapically on an extremely thin. crumpled sheet of apatitic material that is similar to conulariid test material. The conulariids and associated sheet bear a striking resemblance to regenerated, clonal colonies of polypoid coronatid scyphozoans. Such colonies arise from a thin, periderm-covered sheet of non-differentiated soft tissue, produced following severance of a single parent polyp. We suggest that the conulariid cluster originated through a similar process. Should this interpretation be corroborated by the discovery of better preserved conulariid clusters, it would provide strong additional evidence for the hypothesis of a scyphoroan affinity for conulariids