Descriptive anatomy and three-dimensional reconstruction of the skull of the early tetrapod Acanthostega gunnari Jarvik, 1952

PLoS One. 2015 Mar 11;10(3):e0118882. doi: 10.1371/journal.pone.0118882. eCollection 2015.

Abstract

The early tetrapod Acanthostega gunnari is an iconic fossil taxon exhibiting skeletal morphology reflecting the transition of vertebrates from water onto land. Computed tomography data of two Acanthostega skulls was segmented using visualization software to digitally separate bone from matrix and individual bones of the skull from each other. A revised description of cranial and lower jaw anatomy in this taxon based on CT data includes new details of sutural morphology, the previously undescribed quadrate and articular bones, and the mandibular symphysis. Sutural morphology is used to infer loading regime in the skull during feeding, and suggests Acanthostega used its anterior jaws to initially seize prey while smaller posterior teeth were used to restrain struggling prey during ingestion. Novel methods were used to repair and retrodeform the skull, resulting in a three-dimensional digital reconstruction that features a longer postorbital region and more strongly hooked anterior lower jaw than previous attempts while supporting the presence of a midline gap between the nasals and median rostrals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Fossils
  • Jaw / anatomy & histology*
  • Skull / anatomy & histology
  • Vertebrates / anatomy & histology

Grants and funding

This work is funded by a Marie Curie International Incoming Research Fellowship (“Tetrapods Rising”, 303161, (http://cordis.europa.eu/projects/rcn/103929_en.html) to LBP. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.