The cover picture shows the biosynthesis, in the specialized tissue of the opisthobranch mollusc Scaphander lignarius, of the aromatic semiochemical lignarenones. Opisthobranchs are a special group of marine invertebrates that are very well known as an extraordinary source of bioactive natural products. In the article on p. 1759 ff., A. Fontana et al. show that the biosynthesis of lignarenones takes place in specialized mantle cells, the Blochmann's glands, by an unprecedented benzenoid pathway. Synthesis of the polyketide skeleton requires a mixed acetate–propionate assembly that is primed by benzoic acid derived from L-phenylalanine. This last process is gated by enzymatic nonoxidative deamination of the amino acid; this is reminiscent of the transformation catalyzed by phenylalanine ammonia lyases (PALs) in plants and fungi. The article suggests that marine invertebrates possess their own competence for the biosynthesis of natural products, thus challenging the present view on the universal role of microorganisms as the source of functional products in marine benthos.