Combining fossil taxa with and without morphological data improves dated phylogenetic analyses.

Area of Science:

• Paleontology
• Phylogenetics
• Computational Biology

Background:

• The fossilized birth-death (FBD) model is a key method for inferring evolutionary histories of extinct organisms using fossil data.
• Traditionally, placing fossil taxa in phylogenetic trees relies on either morphological data or taxonomic constraints, often treated as separate methods.
• Existing methods often overlook fossil taxa lacking detailed morphological data, limiting comprehensive phylogenetic reconstruction.

Purpose of the Study:

• To implement and evaluate a novel combined approach for phylogenetic inference using both morphological character data and taxonomic constraints within the FBD model.
• To assess the impact of integrating a larger dataset, including taxa with only age information, on phylogenetic accuracy and precision.
• To compare the results of the combined approach with analyses using morphology alone on an empirical trilobite dataset.

Main Methods:

• Utilized a morphological matrix and age data for 56 trilobite taxa, supplemented with age information for an additional 196 taxa from the Paleobiology Database.
• Performed fossilized birth-death (FBD) dated phylogenetic analyses, comparing a combined approach (morphology + taxonomic constraints) against morphology-only analyses.
• Evaluated phylogenetic topologies for stratigraphic congruence, precision of parameter estimates (e.g., divergence times), and tree distribution informativeness.

Main Results:

• The combined approach significantly improved stratigraphic congruence of the inferred phylogenetic trees.
• Parameter estimates, particularly divergence times, were substantially more precise when using the combined dataset.
• The integrated method resulted in more informative phylogenetic tree distributions, reflecting increased stratigraphic age information and better temporal sampling.

Conclusions:

• Integrating morphological data with taxonomic constraints offers a more robust and accurate method for dated phylogenetic inference using the FBD model.
• This combined strategy enhances the precision and reliability of evolutionary reconstructions for extinct taxa, especially when incorporating extensive fossil age data.
• The findings highlight the benefit of utilizing all available stratigraphic information for a more comprehensive understanding of evolutionary history.