Paleozoic ammonoid ecomorphometrics test ecospace availability as a driver of morphological diversification

Area of Science:

• Paleontology
• Evolutionary Biology
• Marine Biology

Background:

• The early burst model posits rapid ecological filling after clade origination or mass extinctions.
• Neontological studies face challenges in identifying early bursts, with morphology changes influenced by non-ecological factors.

Purpose of the Study:

• To investigate ecomorphometric evolution in Ammonoidea over 156 million years.
• To test for evidence of early bursts in ammonoid disparity across multiple radiations and extinction events.

Main Methods:

• Analysis of Ammonoidea ecomorphometric evolution at 1-million-year resolution.
• Examination of data spanning from the Early Devonian (Emsian) to the Early Triassic (Induan).
• Inclusion of time intervals encompassing six global extinction events.

Main Results:

• No evidence of early bursts in ecomorphological disparity was found in Ammonoidea.
• The study covered a ~156 million year period, including major radiations and mass extinctions.

Conclusions:

• The findings challenge the prevalence of early bursts in fossil data.
• Early bursts may be less common than previously assumed, even when considering long temporal scopes and various traits.