The rapid evolution of lungfish durophagy

Area of Science:

• Paleontology
• Evolutionary Biology
• Marine Ecology

Background:

• Hard prey consumption innovations drove marine ecosystem shifts in the mid-Paleozoic.
• Lungfishes are the earliest vertebrate lineage with durophagy (hard prey feeding), but their feeding specializations' origins are unknown.

Purpose of the Study:

• To investigate the origin and evolution of the specialized lungfish feeding mechanism.
• To analyze the feeding adaptations in the Early Devonian lobe-finned fish Youngolepis.

Main Methods:

• Examination of exceptionally preserved Youngolepis fossils.
• Analysis of cranial morphology, including palate restructuring and dentition.
• Bayesian tip-dating analyses incorporating morphological data.

Main Results:

• Youngolepis fossils exhibit a radically restructured palate and radiating entopterygoid tooth rows, similar to lungfish toothplates.
• The presence of marginal dentition and blunt coronoid fangs suggests a crushing function for prey.
• Morphological data indicate the rapid evolution of lungfish feeding specializations within approximately 7 million years.

Conclusions:

• The specialized lungfish feeding mechanism originated in the Early Devonian, as evidenced by Youngolepis.
• This rapid evolutionary innovation contributed to the diversification of bony fishes during their initial radiation.