Produced by: Tarun Mishra
Recent research published in Nature Communications challenges the long-held belief that ammonites were in decline before their extinction 66 million years ago, coinciding with the demise of dinosaurs.
Led by paleontologists from the University of Bristol, the study reevaluates the extinction dynamics of ammonites, extinct marine mollusks related to modern cephalopods like squid and octopus.
Contrary to previous assumptions, the study suggests that ammonites were thriving until their abrupt disappearance alongside dinosaurs, based on a comprehensive database of Late Cretaceous fossil records.
Researchers compiled a new database incorporating global ammonite fossils, leveraging museum collections to fill gaps and provide a more accurate depiction of their biodiversity over time.
Credit: Nobu Tamura
The study highlights significant regional variations in ammonite speciation and extinction rates, challenging the notion of a uniform global decline before the asteroid impact.
Previous theories of global decline were largely based on limited data from North America, whereas the new study reveals diverse evolutionary patterns across different geographic regions.
Factors influencing ammonite diversity included both environmental conditions (Court Jester Hypothesis) and biological processes (Red Queen Hypothesis), showcasing the complexity of their evolutionary history.
By emphasizing regional-scale analyses of fossil datasets, the research underscores the need for nuanced interpretations in paleontology, offering fresh insights into the final stages of ammonite evolution before their extinction event.