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Related Experiment Video

Updated: Dec 21, 2025

Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
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The smallest known Devonian tetrapod shows unexpectedly derived features.

Per E Ahlberg1, Jennifer A Clack2

  • 1Department of Organismal Biology, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden.

Royal Society Open Science
|May 21, 2020
PubMed
Summary

A new tiny Devonian tetrapod, Brittagnathus minutus, was discovered in East Greenland. This smallest-ever Devonian tetrapod provides insights into early tetrapod evolution before the end-Devonian extinction event.

Keywords:
DevonianGreenlandjawtetrapodvertebrate

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Area of Science:

  • Paleontology
  • Vertebrate Paleontology
  • Evolutionary Biology

Background:

  • The Devonian period witnessed the crucial transition of vertebrates from water to land.
  • Understanding early tetrapod diversity is key to reconstructing vertebrate evolutionary history.
  • Fossil discoveries continue to refine our knowledge of Devonian tetrapod lineages.

Purpose of the Study:

  • To describe a new genus and species of Devonian tetrapod, Brittagnathus minutus.
  • To analyze the phylogenetic position and paleoecological implications of this new taxon.
  • To investigate early tetrapod diversification and resilience during the Late Devonian.

Main Methods:

  • Description of a fossilized right lower jaw ramus from East Greenland.
  • High-resolution imaging using propagation phase contrast synchrotron microtomography for digital dissection.
  • Phylogenetic analysis to determine evolutionary relationships.

Main Results:

  • Discovery of Brittagnathus minutus, the smallest Devonian tetrapod described to date (jaw ramus length 44.8 mm).
  • Unique dental and jaw morphology distinguishing it from other Devonian tetrapods, including a fang pair and specific coronoid processes.
  • Phylogenetic placement suggests Brittagnathus is crownward to other Devonian tetrapods, near the Tournaisian genus Pederpes.

Conclusions:

  • Brittagnathus minutus represents a significant addition to the known diversity of early tetrapods.
  • The findings suggest that 'Carboniferous-grade' tetrapod diversification began before the end of the Devonian.
  • Early tetrapods may have been less impacted by the end-Devonian mass extinction than previously thought.