Neuronal cell types in the annelid Platynereis dumerilii.

The marine annelid Platynereis dumerilii is an invertebrate laboratory model for developmental biology and neuroscience. Its larval stages are small and transparent, enabling whole-body analyses of cell-type diversity and neuronal circuits. Here, we review the diversity of neuronal cell types in Platynereis. A variety of approaches have been used to identify cell types in Platynereis including whole-body gene expression atlases, single-cell RNA-seq and whole-body connectomics through serial EM reconstruction. The function of several cell types and neuronal circuits has also been analysed with experimental approaches. Platynereis has aspects of biology and cell types that are absent from the major invertebrate model organisms (C. elegans and Drosophila) including ciliary locomotion, noradrenergic neurons and ciliary photoreceptor cells.