Sea urchins could also be the only most vital consumer affecting shallow marine communities worldwide. Vast seagrass beds and kelp forests are denuded by foraging aggregations of sea urchins leading to loss of habitat, food and changes to the physical environment. On coral reefs, sea urchins shift algal communities from fleshy algae, hostile to corals, to encrusting coralline algae that facilitates coral recruitment and reef resilience. A variety of diseases of sea urchins are found, over a good range of geographical areas and involving many species of both regular and irregular sea urchins. Disease agents starting from bacteria to decapods, but particularly bacteria and parasites, are known to affect sea urchins.  Orthologues of transcription factors that regulate neurogenesis in other animals are identified and a number of other are expressed in neurogenic domains before gastrulation indicating that they'll operate near the top of a conserved neural gene regulatory network.