Early Triassic marine biotic recovery: the predators' perspective

Area of Science:

• Paleontology
• Marine Biology
• Geological History

Background:

• The end-Permian mass extinction was Earth's most severe biotic crisis.
• Ecosystem recovery dynamics, particularly of apex predators, offer insights into recovery patterns.
• Previous models suggest a slow, stepwise biotic recovery lasting millions of years into the Triassic.

Purpose of the Study:

• To investigate the trophic structure of marine ecosystems following the end-Permian mass extinction.
• To assess the recovery tempo and pattern by analyzing marine predatory vertebrates.
• To evaluate the height of trophic pyramids in the Early Triassic and Anisian periods.

Main Methods:

• Surveying the global distribution and body size spectra of Early Triassic and Anisian marine predatory vertebrates (fishes, amphibians, reptiles).
• Compiling maximum standard lengths for fishes and estimated total sizes for tetrapods.
• Qualitative assessment of tetrapod distribution and size spectra due to preservation challenges.

Main Results:

• No significant increase in predator body size was observed from the Early Triassic to the Anisian.
• Evidence suggests the existence of marine ecosystems with multiple trophic levels from the earliest Early Triassic.
• A significant taxonomic shift in predatory guilds occurred within two million years post-extinction, moving from fish/amphibian to fish/reptile dominance.

Conclusions:

• The recovery of marine ecosystems, in terms of trophic complexity, was more rapid than previously assumed.
• Predatory guilds underwent a taxonomic reorganization early in the Triassic, indicating ecosystem restructuring.
• The findings challenge the paradigm of a prolonged, stepwise recovery of marine ecosystems after the end-Permian event.