Early internal-shell characters are used to infer relationships near the origin of sampled Ceratitida; this comparative inference is not a directly observed ancestor or a complete global first appearance.
claim:taxon:ceratitidaAtlas home / References / Origin of the Ceratitida (Ammonoidea) inferred from the early internal shell features
References / paperOrigin of the Ceratitida (Ammonoidea) inferred from the early internal shell features
Shigeta, Y.; Zakharov, Y.D.; Mapes, R.H.
Year2001
Source roleprimary-study
DOI / ID10.2517/prpsj.5.201
Fitness and scope
taxonomy · topology · morphology · range
Comparative internal-shell analysis infers ceratitid relationships and explicitly states an Early Permian–end-Triassic order range; inferred ancestry and continuous occupancy remain unclaimed.
Claim ledger
Shigeta et al. explicitly state that Ceratitida ranged from the Early Permian to the end of the Triassic; the atlas converts those named period bounds to 298.9–201.4 Ma with ICS v2026/06 without implying direct dates, continuous preservation or ancestry.
claim:taxon:ceratitida:source-bounded-range-rc50