摘要：SummaryCtenophores are a group of predatory macroinvertebrates whose controversial phylogenetic position has prompted several competing hypotheses regarding the evolution of animal organ systems. Although ctenophores date back at least to the Cambrian, they have a poor fossil record due to their gelatinous bodies. Here, we describe two ctenophore species from the Cambrian of Utah, which illuminate the early evolution of nervous and sensory features in the phylum.Thalassostaphylos eleganshas 16 comb rows, an oral skirt, and an apical organ with polar fields.Ctenorhabdotus campanelliformishas 24 comb rows, an oral skirt, an apical organ enclosed by a capsule and neurological tissues preserved as carbonaceous films. These are concentrated around the apical organ and ciliated furrows, which connect to a circumoral nerve ring via longitudinal axons. C. campanelliformisdeviates from the neuroanatomy of living ctenophores and demonstrates a substantial complexity in the nervous system of Cambrian ctenophores.Graphical abstractDisplay OmittedHighlights•Two species of rare fossil ctenophores are described from the Cambrian of Utah•Fossil ctenophores preserve remains of nervous tissue and sensory structures•Neurological structures include an oral nerve ring and giant longitudinal axons•Cambrian ctenophores had a more complex neuroanatomy than living speciesBiological sciences; Evolutionary biology; Phylogenetics
