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Updated: May 30, 2026
07:26
Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
Published on: August 22, 2022
Archaeocete-like jaws in a baleen whale
1Museum Victoria, Melbourne, Victoria, Australia. eiluned.pearce@anthro.ox.ac.uk
Biology Letters
|August 19, 2011
Summary
Baleen whales evolved large mouths before filter feeding. Early mysticetes had a sutured jaw, suggesting suction feeding on prey, not plankton, drove initial skull changes.
Area of Science:
- Paleontology
- Marine Biology
- Evolutionary Biology
Background:
- Baleen whales (Mysticeti) possess unique skull morphology for bulk feeding, including an elastic mandibular symphysis.
- The evolutionary transition from the sutured symphysis of ancestral archaeocetes to the elastic symphysis of modern mysticetes remains poorly understood.
Purpose of the Study:
- To investigate the early evolution of mysticete cranial morphology and its relation to feeding strategies.
Main Methods:
- Analysis of mandibular fossils of Janjucetus hunderi, an Oligocene toothed mysticete.
- Comparative morphological analysis with archaeocetes and later mysticetes.
Main Results:
- Janjucetus hunderi exhibits an archaeocete-like sutured mandibular symphysis.
- This archaic jaw structure was combined with a wide rostrum, characteristic of later baleen whales.
- Rostral widening for increased oral capacity predates the evolution of the elastic mandibular symphysis.
Conclusions:
- The initial evolution of large mouths in mysticetes was likely driven by enhanced suction feeding on individual prey.
- This contrasts with the prevailing hypothesis linking early mysticete cranial evolution directly to filter feeding on plankton.
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