How to fail at species delimitation

Area of Science:

• Evolutionary Biology
• Genetics
• Biodiversity Science

Background:

• Species delimitation is crucial for understanding biological diversity.
• Numerous methods exist, but studies often use only a few, limiting robustness.
• Existing methods rely on simplifying assumptions that may not hold true for all systems.

Purpose of the Study:

• To advocate for the application of a wide range of species delimitation methods.
• To emphasize the importance of congruence across methods for reliable species identification.
• To guide researchers in interpreting results when methods yield incongruent outcomes.

Main Methods:

• Review of current species delimitation methodologies.
• Comparative analysis of assumption sets for different species delimitation approaches.
• Framework for evaluating congruence and incongruence in species delimitation results.

Main Results:

• Most studies use a limited subset of available species delimitation techniques.
• Methodological assumptions can be violated, leading to potential errors in species identification.
• Incongruence across methods signals potential issues with method assumptions or lineage detection power.

Conclusions:

• Researchers should employ diverse species delimitation analyses on their data.
• Trust in species delimitations should be based on congruence across multiple methods.
• Conservative inferences are recommended; failing to delimit is preferable to falsely identifying lineages.