Temperature-driven heterochrony as a main evolutionary response to climate changes in conodonts

Area of Science:

• Paleontology
• Evolutionary Biology
• Climate Science

Background:

• Organisms' evolutionary trajectories are influenced by phenotypic variance and developmental processes.
• Heterochrony, a modification of developmental timing, is crucial for rapid adaptation.
• Understanding static vs. ontogenetic allometry is key to predicting evolutionary responses.

Purpose of the Study:

• To investigate conodont evolutionary responses to climate change.
• To compare static and ontogenetic allometry patterns during environmental crises.
• To determine if evolution follows the line of least resistance or heterochrony.

Main Methods:

• Quantified morphology of segminiplanate conodont elements.
• Analyzed specimens from the Devonian-Carboniferous and Carnian-Norian boundaries.
• Compared static allometry patterns with evolutionary trajectories.

Main Results:

• Conodont species exhibited similar static allometry patterns across different time intervals.
• Evolutionary trajectories during crises deviated from the common line of least resistance.
• Conodont evolution followed heterochrony-like paths, driven by ocean temperature.

Conclusions:

• Static allometry does not fully predict evolutionary responses to climate change.
• Heterochrony played a significant role in conodont adaptation during past environmental perturbations.
• Ocean temperature is a key driver of evolutionary trajectories during climate crises.