A genome-based phylogeny for Mollusca is concordant with fossils and morphology
Zeyuan Chen, J. Antonio Baeza, Chong Chen, María Teresa González, Vanessa L. González, Carola Greve, Kevin M. Kocot, Pedro Martínez Arbizu, Juan Moles, Tilman Schell, Enrico Schwabe, Jin Sun, Nur Leena W. S. Wong, Meghan K. Yap-Chiongco, Julia D. Sigwart
Abstract
Extreme morphological disparity within Mollusca has long confounded efforts to reconstruct a stable backbone phylogeny for the phylum. Familiar molluscan groups-gastropods, bivalves, and cephalopods-each represent a diverse radiation with myriad morphological, ecological, and behavioral adaptations. The phylum further encompasses many more unfamiliar experiments in animal body-plan evolution. In this work, we reconstructed the phylogeny for living Mollusca on the basis of metazoan BUSCO (Benchmarking Universal Single-Copy Orthologs) genes extracted from 77 (13 new) genomes, including multiple members of all eight classes with two high-quality genome assemblies for monoplacophorans. Our analyses confirm a phylogeny proposed from morphology and show widespread genomic variation. The flexibility of the molluscan genome likely explains both historic challenges with their genomes and their evolutionary success.