Triassic stem caecilian supports dissorophoid origin of living amphibians

Funcusvermis gilmorei from the Norian upper Blue Mesa Member is a stem gymnophionomorph in the published analyses, extending the sampled caecilian total-group record to about 221 Ma without dating crown Gymnophiona.

At least 76 individuals represented by isolated three-dimensional Funcusvermis elements occur in a U–Pb-bracketed Norian bonebed and support a caecilian total-group record, but not crown Gymnophiona, one articulated animal or a global first appearance.

Funcusvermis gilmorei is represented by isolated elements from at least seventy-six individuals and was recovered as a stem gymnophionomorph outside crown Gymnophiona.

The represented Funcusvermis sample comes from the Thunderstorm Ridge bonebed in the upper Blue Mesa Member of Arizona; one bonebed does not establish global distribution.

The disarticulated bones permit limited functional inference but do not directly establish diet, burrowing behaviour, locomotor performance or habitat preference.

Three-dimensional jaws, vertebrae and femora preserve a character combination used to place Funcusvermis on the caecilian total-group stem.

The displayed 223.036–218.043 Ma interval is the U–Pb-bracketed Norian bonebed envelope and is not a crown-Gymnophiona or global lissamphibian FAD.

After documenting 4,200 corrected matrix cells and adding 56 terminal taxa, one expanded morphology analysis recovered a lepospondyl-origin tree as 9–10 steps shorter than constrained temnospondyl alternatives, while reporting generally low bootstrap support.

The Chinlestegophis analysis placed two Late Triassic skulls on the caecilian stem and drew stereospondyls into Lissamphibia, whereas the later Funcusvermis analysis recovered a dissorophoid gymnophionomorph stem and did not retain that stereospondyl-caecilian route.

The Amphibian fossil evidence route navigation entity is source-linked only to the named specimen, dataset and analysis dossiers already cited by its range ledger. Its displayed span is a study-bounded route or sample envelope, not a biological taxon, ancestor sequence, global FAD/LAD or exact origin interval.

Competing lissamphibian-origin hypotheses change which Paleozoic and Triassic fossils can bound the group, so the former 250 Ma–present composite is withheld pending a declared crown/total definition and hypothesis-specific calibration.