Finding a home for hyoliths

A new interpretation of hyoliths, ancient conical-shelled organisms, challenges their classification as brachiopods. Liu et al. propose that hyoliths instead belong to the Lophotrochozoa clade, which includes molluscs and annelids, by re-evaluating their feeding apparatus and shell structures. The study questions the validity of a previously described attachment stalk in Chengjiang fossils, suggesting it may be a damaged shell apex rather than a true pedicle. This reinterpretation has significant evolutionary implications, implying that the ancestral lophotrochozoan had a shell, which was later lost in annelids. The research combines morphological analysis and phylogenetic reconstruction to reshape our understanding of early animal evolution.

Smith, M. R. (2019). Finding a home for hyoliths. National Science Review, 7(2), 470–471. https://doi.org/10.1093/nsr/nwz194