Data from: Background extinction due to species specialization? Insights from a high-resolution Jurassic ammonoid case study (Dactylioceratidae)

The extinction of clades outside mass extinction events remains an
understudied aspect of evolutionary dynamics. This study examines the
Dactylioceratidae, an ammonite family that disappeared during the Early
Jurassic, outside a recognized mass extinction event. By using
high-resolution taxonomic (species-level) and temporal (sub-chronozone)
data, we assess its evolutionary trajectory, from diversification to
extinction. Our analysis reveals that Dactylioceratidae experienced an
initial expansion in diversity and geographic range, followed by increased
specialization. Morphological disparity and diversity peaked before a
sharp decline, suggesting a possible link between ecological
specialization and extinction risk. This pattern aligns with hypotheses
proposing that over-specialization limits adaptability, leading to
extinction under background conditions. In contrast to mass extinctions
driven by sudden catastrophic events, background extinctions may be
influenced by gradual ecological changes and evolutionary constraints. By
comparing the case of Dactylioceratidae with broader ammonoid trends, this
study provides insights into long-term extinction mechanisms. These
findings are relevant for understanding both past and present biodiversity
crises, shedding light on how species’ evolutionary strategies impact
their survival over time.