Modelling determinants of extinction across two Mesozoic hyperthermal events.

Area of Science:

• Paleontology
• Marine Biology
• Climate Science

Background:

• The Late Triassic and Early Toarcian extinction events were linked to massive volcanism and greenhouse warming.
• These Mesozoic hyperthermals caused significant marine organism extinctions and ecological disruption.
• Previous research debated whether these events altered extinction selectivity or merely intensified background rates.

Purpose of the Study:

• To test if extinction selectivity varied during the Late Triassic and Early Jurassic hyperthermals.
• To analyze macroevolutionary regime shifts and extinction patterns during these critical periods.

Main Methods:

• Application of a multivariate modeling approach.
• Analysis of a comprehensive global database of marine organisms.

Main Results:

• Hyperthermals represent significant shifts in the macroevolutionary regime and extinction selectivity.
• Both Late Triassic and Early Toarcian events showed distinct extinction selectivity compared to background intervals.
• Common vulnerability observed in pelagic predators, benthic photosymbiotic, and suspension-feeding organisms.

Conclusions:

• The Late Triassic extinction demonstrated a more profound change in selectivity than the Early Toarcian event.
• Both events reveal a pattern of vulnerability for specific marine groups during global warming.
• The Late Triassic extinction signifies a macroevolutionary regime change, distinct from background intervals and the Early Jurassic.