1. Triassic stem caecilian supports dissorophoid origin of living amphibians  Nature.com
  2. 'Funky Worm' Fossil Helps Explain The Mysterious Origins of Amphibians  ScienceAlert
  3. One wormy Triassic fossil could fill a hole in the evolutionary story of amphibians  Popular Science
  4. New geosciences study shows Triassic fossils that reveal origins of living amphibians  Phys.org
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Living amphibians (Lissamphibia) include frogs and salamanders (Batrachia) and the limbless worm-like caecilians (Gymnophiona). The estimated Palaeozoic era gymnophionan–batrachian molecular divergence1 suggests a major gap in the record of crown lissamphibians prior to their earliest fossil occurrences in the Triassic period2–6. Recent studies find a monophyletic Batrachia within dissorophoid temnospondyls7–10, but the absence of pre-Jurassic period caecilian fossils11,12 has made their relationships to batrachians and affinities to Palaeozoic tetrapods controversial1,8,13,14. Here we report the geologically oldest stem caecilian—a crown lissamphibian from the Late Triassic epoch of Arizona, USA—extending the caecilian record by around 35 million years. These fossils illuminate the tempo and mode of early caecilian morphological and functional evolution, demonstrating a delayed acquisition of musculoskeletal features associated with fossoriality in living caecilians, including the dual jaw closure mechanism15,16, reduced orbits17 and the tentacular organ18. The provenance of these fossils suggests a Pangaean equatorial origin for caecilians, implying that living caecilian biogeography reflects conserved aspects of caecilian function and physiology19, in combination with vicariance patterns driven by plate tectonics20. These fossils reveal a combination of features that is unique to caecilians alongside features that are shared with batrachian and dissorophoid temnospondyls, providing new and compelling evidence supporting a single origin of living amphibians within dissorophoid temnospondyls. Analysis of fossils of the oldest known caecilian provide insights into the origin and morphological and functional evolution of caecilians.Nature - Analysis of fossils of the oldest known caecilian provide insights into the origin and morphological and functional evolution of caecilians.

Triassic stem caecilian supports dissorophoid origin of living amphibians | Nature

Paleontologists from Virginia Tech, the U.S. Petrified Forest National Park, and other institutions have found the first clear Triassic-era caecilianPaleontologists from Virginia Tech, the U.S. Petrified Forest National Park, and other institutions have found the first clear Triassic-era caecilian

Triassic Breakthrough: First-Ever Caecilian Fossils Found in Arizona Reveal Origins of Living Amphibians