The palaeobiology of two crown group cnidarians: Haootia quadriformis and Mamsetia manunis gen. et sp. nov. from the Ediacaran of Newfoundland, Canada

Haootia preserves repeated aligned impressions in a tetraradial body, interpreted as muscle bundles and compared with Staurozoa, but fibre identity and detailed homology have competing primary assessments.

Haootia preserves repeated aligned impressions in one Ediacaran holotype, but muscle identity, orientation and staurozoan comparison have competing primary interpretations; the specimen does not set a Staurozoa or Cnidaria range.

Haootia is displayed at approximately 560 Ma only as the age estimate for its type material used by competing muscular-cnidarian interpretations; it is not a crown-Staurozoa FAD, direct ancestor or global genus duration.

Haootia quadriformis is retained as an Ediacaran cnidarian candidate because the holotype was described in a muscular-cnidarian framework, while later primary studies dispute the staurozoan comparison and keep its precise placement open.

The Haootia holotype NFM F-994 comes from the Fermeuse Formation on the Bonavista Peninsula of Newfoundland, Canada; this named occurrence does not establish a complete geographic distribution or origin centre.

The Haootia holotype preserves a roughly quadrate body impression with repeated aligned internal structures; muscle identity and their orientation remain competing interpretations rather than observed histology.