Follow named specimens, CT datasets, character matrices and living experiments while keeping anatomy, topology, function, crown membership and time explicitly separate.
Each step names its evidence claims, with references below. Interactive Explorer states are available in the full application; the narrative remains an editorial synthesis.
ROM VP 83326 records striking neural-spine elongation in a referred early synapsid. Missing surrounding anatomy prevents the specimen from fixing whole-body proportions, function or a lineage-wide first appearance.
A referred bone, a reconstructed body outline and a proposed sail function are three different evidence levels.
claim:event:echinerpeton-neural-spine-specimenThe partial snout IVPP V15424 was recovered beside the remaining sampled therapsids in one 71-character analysis. That topology is reproducible evidence, not direct ancestry or a precisely dated origin event.
The paper itself warns that the Dashankou sequence lacks reliable radiometric dates.
claim:event:raranimus-basal-therapsid-snoutRiograndia has dentary–squamosal contact while the nine-specimen Brasilodon sample lacks it. The distribution supports iterative acquisition, and contact alone neither creates a crown mammal nor proves modern joint function.
The 225.42 ± 0.37 Ma value is a maximum depositional age, not a direct fossil date.
claim:event:riograndia-brasilodon-jaw-joint-homoplasyCT anatomy and wear from MCZ7/95A–B and MCZ10/G95 reshaped a published matrix that placed Haramiyavia outside crown Mammalia. The placement belongs to that analysis, while the jaw surface only indirectly supports auditory anatomy.
A matrix placement, a crown calibration and an anatomical observation are not interchangeable.
claim:event:haramiyavia-ct-crown-boundaryDianoconodon and Feredocodon preserve different jaw–ear combinations across two formations and times. Their comparison supports a load shift, but it is not a continuous transformation series or an ancestor–descendant pair.
Preserved contacts support, but do not directly measure, biting and hearing performance.
claim:event:jurassic-mammaliaform-jaw-ear-load-shiftIVPP V16051 preserves ectotympanic and malleus elements separated from direct dentary contact yet connected by ossified Meckel's cartilage. One articulated skeleton documents a mosaic, not a universal evolutionary stage.
Anatomical connection is observed; stabilization and auditory effects remain functional inference.
claim:event:liaoconodon-ossified-meckel-linkMouse genetics and opossum inhibition experiments show that disrupting clast-cell activity can retain a jaw–ear cartilage connection. They illuminate a possible mechanism without replaying a particular fossil or proving its ancient cause.
COL26.8 assigns zero accepted species directly to mammal-origins because living Mammalia route to order-specific or other-mammals packages and Synapsida lacks a reliable materialized species root. Zero is a routing boundary, not evidence of no living synapsids, no nomenclatural coverage or complete dossier maturity.
claim:event:meckel-cartilage-clast-experiment