Octopus bimaculatus
Octopus bimaculatus, commonly referred to as Verill's two-spot octopus, is a similar species to the Octopus bimaculoides, a species it is often mistaken for. The two can be distinguished by the difference in the blue and black chain-like pattern of the ocelli. O. bimaculatus hunt and feed on a diverse number of benthic organisms that also reside off the coast of Southern California. Once the octopus reaches sexual maturity, it shortly dies after mating, which is approximately 12–18 months after hatching. Embryonic development tends to be rapid due to this short lifespan of these organisms. Description Octopus bimaculatus is typically light brown and spotted in color with a distinctive blue and black false eye, or ocellus, under each eye. The mantle, including the beak and mouth, is located at the center of eight arms. Each of the arms is lined with suckers that are used to help with grasping prey, rocks, and forming shelters. Similar to other octopus species, O. bimaculatus has skin covered in chromatophores. During the post-larval stage, there are only a few chromatophores and they are called the "founder chromatophores." However, as the octopus matures, more chromatophores form and cover the skin. These chromatophores are pigments that the octopus can expand to create large disc of color that can blend in with the surrounding environment. This is an important behavior that can be used in both defense against predators or to remain hidden from prey before an ambush attack. Fully mature octopus grow to be about 18 inches long. Distinctive features O. bimaculatus gets its name "two-spotted octopus" from the blue and black ocelli under each eye. One potential function of these bright blue ocelli is to allow the octopus to appear as a different animal with large eyes as it swims swiftly through the water. O. bimaculatus is often confused with Octopus bimaculoides due to the similarity in looks, however they are two different species. They both have these two distinctive black and blue ocelli beneath the eyes and above the arms, however there are a few key differences in their features to tell the two species apart. The blue ring of the ocelli for Octopus bimaculatus does not have the same distinctive chain-like pattern that the Octopus bimaculoides has. For O. bimaculatus the pattern is still chain-like but more irregular, asymmetrical, and disproportionate while for O. bimaculoides the chain-like pattern is more symmetrical and orderly. The two also differ in egg size, with Octopus bimaculatus eggs being much smaller that hatch into planktonic larvae rather than benthic hatchlings like Octopus bimaculoides. Additionally, octopus bimaculatus is generally the larger of the two species. Feeding Diet O. bimaculatus is known to prey on crustaceans, snails, chitons, limpets, and bivalves. Studies have observed the predator-prey interactions between the O. bimaculatus and the Californian Scorpionfish (Scorpaena guttata) in aquariums. Findings suggest that the Californian Scorpionfish is included in the diet of O. bimaculatus in their natural habitat, specifically juvenile scorpionfish. As juveniles, the octopus tend to prey on smaller