A mitogenomic phylogeny of chitons (Mollusca: Polyplacophora)

BMC Evolutionary Biology

article

Irisarri, Iker¹  Uribe, Juan E.¹  Eernisse, Douglas J.⁴  Zardoya, Rafael¹ 

[1] Department of Biodiversity and Evolutionary Biology;Department of Organismal Biology (Systematic Biology Program), Evolutionary Biology Centre, Uppsala University;Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History;Department of Biological Science, California State University Fullerton

关键词: Bayesian;    Evolution;    Fossil;    Maximum likelihood;    Mitochondrial genome;    Molecular clock;    Mollusk;    Mt;    Timetree;   

DOI  :  10.1186/s12862-019-1573-2

学科分类：护理学

来源: BioMed Central

【 摘 要 】

Polyplacophora, or chitons, have long fascinated malacologists for their distinct and rather conserved morphology and lifestyle compared to other mollusk classes. However, key aspects of their phylogeny and evolution remain unclear due to the few morphological, molecular, or combined phylogenetic analyses, particularly those addressing the relationships among the major chiton lineages. Here, we present a mitogenomic phylogeny of chitons based on 13 newly sequenced mitochondrial genomes along with eight available ones and RNAseq-derived mitochondrial sequences from four additional species. Reconstructed phylogenies largely agreed with the latest advances in chiton systematics and integrative taxonomy but we identified some conflicts that call for taxonomic revisions. Despite an overall conserved gene order in chiton mitogenomes, we described three new rearrangements that might have taxonomic utility and reconstructed the most likely scenario of gene order change in this group. Our phylogeny was time-calibrated using various fossils and relaxed molecular clocks, and the robustness of these analyses was assessed with several sensitivity analyses. The inferred ages largely agreed with previous molecular clock estimates and the fossil record, but we also noted that the ambiguities inherent to the chiton fossil record might confound molecular clock analyses. In light of the reconstructed time-calibrated framework, we discuss the evolution of key morphological features and call for a continued effort towards clarifying the phylogeny and evolution of chitons.

【 授权许可】

CC BY|CC0