Polycyathus muellerae

Polycyathus muellerae is a small colonial coral species belonging to the family Caryophylliidae. It is characterized by its large polyps, which are initially connected by an encrusting basal lamina. Over time, this lamina can wear away, allowing other organisms to inhabit the spaces between the polyps. The colonies can spread to about a meter in diameter, with individual polyps residing in corallites that are approximately 6 mm in diameter and 10 mm in height. The corallites feature up to four cycles of toothed septa, totaling 48 septa. Both the polyps and corallites are brown, and the tentacles are adorned with white granulations and cylindrical tips. This coral species is native to the northeastern Atlantic Ocean, including the North Sea, the English Channel, and the Mediterranean Sea. It thrives in poorly lit environments, typically found under overhangs and in caves at depths of 30 meters or less. Unlike many corals, Polycyathus muellerae does not engage in a symbiotic relationship with zooxanthellae. Instead, it feeds on planktonic organisms captured by its polyps. Reproduction in Polycyathus muellerae is primarily asexual through budding, although sexual reproduction is likely given its widespread distribution. This species is sometimes parasitized by the barnacle Megatrema anglicum. Despite its presence in various regions, the conservation status of Polycyathus muellerae has not been evaluated.