Pojetaia runnegari shell sections preserve laminar inner fabric comparable to foliated aragonite, while undisputed nacre and broader evolutionary precursors remain interpretive.
claim:taxon:pojetaiaPojetaia runnegari
More than fifty Pojetaia runnegari shell specimens from probably Botomian Ajax Limestone and lowermost Botomian Erkeket Formation preserve a laminar inner fabric comparable to foliated aragonite; the paper does not identify undisputed Cambrian nacre.
Represented range514.5–506.5 Ma
Content packagemolluscs-brachiopods
PBDBtxn:65583
Evidence boundary
Automated checks cover structure, identifiers, translations and links only; maintainer and external expert review are not complete.
Claim ledger
More than fifty Pojetaia specimens from probably Botomian Ajax Limestone and lowermost Botomian Erkeket Formation units support a Cambrian Stage 4 sample envelope of 514.5–506.5 Ma; this is not an exhaustive global genus FAD or LAD.
claim:taxon:pojetaia:source-bounded-range-rc50Vendrasco et al. treat the studied shell material as Pojetaia runnegari; the profile retains that species-level identification while keeping bivalve-wide evolutionary placement conditional.
claim:taxon:pojetaia:taxonomyThe documented Pojetaia runnegari shell sample is bounded to the Ajax Limestone and Erkeket Formation of South Australia; these localities do not establish the complete geographic distribution of the genus.
claim:taxon:pojetaia:biogeographyPojetaia shell sections document mineralized shell microstructure but do not directly preserve feeding, locomotion, body size or ecological guild; any shallow-marine setting is limited to the sampled formations.
claim:taxon:pojetaia:ecologyKnown limits
- A missing branch or fossil occurrence does not imply biological absence. Internal nodes are not calibrated divergence estimates.
References
- Shell microstructure of the early bivalve Pojetaia and the independent origin of nacre within the MolluscaVendrasco, M.J.; Checa, A.G.; Kouchinsky, A.V. · 2011 · DOI 10.1111/j.1475-4983.2011.01056.x
- International Chronostratigraphic Chart v2026/06Cohen, K.M.; Harper, D.A.T.; Gibbard, P.L.; Car, N. · 2026 · DOI 10.18814/epiiugs/2025/025001
- Open Tree of Life web servicesOpenTreeOfLife Project
- The Paleobiology Database application programming interfacePeters, S.E.; McClennen, M. · 2016 · DOI 10.1017/pab.2015.39
- Denormalized occurrence and taxon tables of the Paleobiology DatabaseThe Paleobiology Database Community; Kocsis, Á.T. · 2026 · DOI 10.5281/zenodo.21620933