Consensus and confusion in molluscan trees: evaluating morphological and molecular phylogenies

Area of Science:

• * Zoology and evolutionary biology, focusing on animal phyla diversification.
• * Phylogenetics and comparative genomics of invertebrate species.

Background:

• * Mollusks represent a highly diverse animal phylum with a rich fossil record, yet their evolutionary history and class relationships remain debated.
• * Morphological and molecular studies have yielded conflicting hypotheses regarding molluscan phylogeny and early radiation patterns.

Purpose of the Study:

• * To analyze existing phylogenetic data to resolve ambiguities in molluscan evolutionary relationships.
• * To evaluate the resolution of molluscan phylogeny against null models and identify robust patterns of relatedness.

Main Methods:

• * Compilation and analysis of 42 published phylogenetic trees for mollusks.
• * Construction of supertrees using multiple methods and data partitions from molecular phylogenies.
• * Algorithmic evaluation of disparate published topologies to identify consistent relationships.

Main Results:

• * Morphological data yield limited statistically distinct trees, while molecular data show significant variation and controversy.
• * Consistent proximity observed between Monoplacophora and Polyplacophora (chitons), supporting their close evolutionary relationship.
• * Rarely proximate pairings, such as Caudofoveata and Bivalvia, highlight distant evolutionary connections.

Conclusions:

• * The study identifies specific taxon pairs with strong evidence for relatedness, guiding future research.
• * Results aid in planning targeted research for resolving phylogenetic uncertainties in mollusks and other complex groups.
• * Identified proximate and distant taxa are crucial for selecting exemplars in higher-level phylogenomic analyses.