Situational motionless camouflage of a loliginid squid.

Coleoid cephalopods have the most elaborate camouflage system in the animal kingdom. This enables them to hide from or deceive both predators and prey. Most studies have focused on benthic species of octopus and cuttlefish, while studies on squid focused mainly on the chromatophore system for communication. Camouflage adaptations to the substrate while moving has been recently described in the semi-pelagic oval squid (Sepioteuthis lessoniana). Our current study focuses on the same squid's complex camouflage to substrate in a stationary, motionless position. We observed disruptive, uniform, and mottled chromatic body patterns, and we identified a threshold of contrast between dark and light chromatic components that simplifies the identification of disruptive chromatic body pattern. We found that arm postural components are related to the squid position in the environment, either sitting directly on the substrate or hovering just few centimeters above the substrate. Several of these context-dependent body patterns have not yet been observed in S. lessoniana species complex or other loliginid squids. The remarkable ability of this squid to display camouflage elements similar to those of benthic octopus and cuttlefish species might have convergently evolved in relation to their native coastal habitat.