Morphological, molecular, and behavioral characterization of a ganglion-like oral nerve ring in the sea anemone Nematostella vectensis [RNA-seq]

While neural centralization is typically associated with Bilateria, the sister taxon Cnidaria (jellyfish, sea anemones, and corals) possesses nerve nets that can nevertheless harbor localized neural specializations. Despite growing recognition of these specializations, an integrated understanding of their anatomical organization, molecular identity, and behavioral roles remains limited.

Here, we show that the sea anemone Nematostella vectensis possesses an oral nerve ring (ONR) marked by soma-level neuronal condensations near tentacle junctions and circumferential neurites. This organization emerges during the larval-to-polyp transition and becomes more pronounced during subsequent development. Single-cell analysis reveals that ONR-associated neurons express diverse neurotransmitter receptors yet few sensory or ciliary signatures, defining a receptor-rich molecular profile with potential for input integration.