When Homoplasy Is Not Homoplasy: Dissecting Trait Evolution by Contrasting Composite and Reductive Coding

Area of Science:

• Phylogenetic Systematics
• Evolutionary Biology
• Plant Taxonomy

Background:

• Character coding in phylogenetic systematics is challenging, with no consensus on complex vs. simple character representation.
• Composite coding can obscure independent evolutionary events, misinterpreting them as complex characters.

Purpose of the Study:

• To propose and test an iterative reductive coding method for complex characters in phylogenetic analysis.
• To evaluate character homology hypotheses using reciprocal illumination and phylogenetic analysis.

Main Methods:

• Developed an iterative reductive coding approach for complex characters.
• Applied this method to analyze fruit evolution within the Cinchonoideae subfamily (Rubiaceae).
• Utilized phylogenetic analysis to assess homology and homoplasy of fruit characters.

Main Results:

• Iterative reductive coding successfully resolved complex fruit characters in Cinchonoideae.
• Demonstrated that drupes and berries within Cinchonoideae are not homologous.
• Identified the need for a refined ontology for Cinchonoideae drupes.

Conclusions:

• Iterative reductive coding is a valuable method for refining phylogenetic hypotheses when homology is uncertain.
• The study clarifies fruit evolution in Cinchonoideae, revising previous interpretations of drupe and berry homology.
• A more precise taxonomic framework for Cinchonoideae drupes is necessary.