Octopuses are soft-bodied, eight-limbed molluscs of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.
Blue-ringed octopuses, comprising the genus Hapalochlaena, are four highly venomous species of octopus that are found in tide pools and coral reefs in the Pacific and Indian oceans, from Japan to Australia. They can be identified by their yellowish skin and characteristic blue and black rings that change color dramatically when the animal is threatened. They eat small crustaceans, including crabs, hermit crabs, shrimp, and other small sea animals.
The blacktip reef shark is a species of requiem shark, in the family Carcharhinidae, which can be easily identified by the prominent black tips on its fins. Among the most abundant sharks inhabiting the tropical coral reefs of the Indian and Pacific Oceans, this species prefers shallow, inshore waters. Its exposed first dorsal fin is a common sight in the region. The blacktip reef shark is usually found over reef ledges and sandy flats, though it has also been known to enter brackish and freshwater environments. It typically attains a length of 1.6 m (5.2 ft).
The mimic octopus is an Indo-Pacific species of octopus from the Indo-Pacific region. Like other octopuses, it uses its chromatophores to disguise itself with its background. However, it is noteworthy for being able to impersonate a wide variety of other marine animals. Although many animals mimic either their environment or other animals to avoid predation, the mimic octopus and its close relative the wunderpus are the only ones known to actively imitate a number of animals in order to elude predators.
Octopus is the largest genus of octopuses, comprising more than 100 species. These species are widespread throughout the world's oceans. Many species formerly placed in the genus Octopus are now assigned to other genera within the family Octopodidae.
The silvertip shark is a large species of requiem shark, in the family Carcharhinidae, with a fragmented distribution throughout the tropical Indian and Pacific Oceans. It is often encountered around offshore islands and coral reefs, and has been known to dive to a depth of 800 m (2,600 ft). The silvertip shark resembles a larger and bulkier grey reef shark, but can be easily identified by the prominent white margins on its fins. It attains a maximum length of 3 m (10 ft).
Octopus cyanea, also known as the big blue octopus or day octopus, is an octopus in the family Octopodidae. It occurs in both the Pacific and Indian Oceans, from Hawaii to the eastern coast of Africa. O. cyanea grows to 16 cm in mantle length with arms to at least 80 cm. This octopus was described initially by the British zoologist John Edward Gray in 1849; the type specimen was collected off Australia and is at the Natural History Museum in London.
Velodona togata is a species of octopus in the monotypic genus Velodona. First described by Carl Chun in 1915, with a second subspecies discovered by Guy Coburn Robson in 1924, it was named for the distinctive membranes on its arms.
Abdopus is a genus of octopuses in the family Octopodidae.
The longnose hawkfish is a species of marine ray-finned fish, a hawkfish belonging to the family Cirrhitidae. It is found on tropical reefs of the Indian Ocean and the Pacific Ocean, where it can be found at depths around 10 to 100 m. It prefers the steep outer slopes of the reefs amongst gorgonians and black corals. This species can reach 13 cm (5.1 in) in total length. It can also be found in the aquarium trade. It is currently the only known member in its genus.
Callistoctopus macropus, also known as the Atlantic white-spotted octopus, white-spotted octopus, grass octopus or grass scuttle, is a species of octopus found in shallow areas of the Mediterranean Sea, the warmer parts of the eastern and western Atlantic Ocean, the Caribbean Sea, and the Indo-Pacific region. This octopus feeds on small organisms which lurk among the branches of corals.
Mulloidichthys is a genus of fish in the family Mullidae native to coral and rocky reefs of the tropical Atlantic, Indian and Pacific Ocean.
Callistoctopus ornatus is a tropical species of octopus native to the Indo-Pacific region. Other common names include white-striped octopus and night octopus, in reference to its nocturnal habits. It was previously known as Polypus ornatus. C. ornatus is edible and was recorded in a Hawaiian market in 1914 by S. S. Berry.
The roving coral grouper, also known as the spotted coral grouper, is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the anthias and sea basses. It is found in the Indo-Pacific, although the Red Sea taxon, P.. marisrubri, is regarded as a separate species by some authorities.
Sepioteuthis lessoniana, commonly known as the bigfin reef squid, glitter squid or oval squid, is a species of loliginid squid. It is one of the three currently recognized species belonging to the genus Sepioteuthis. Studies in 1993, however, have indicated that bigfin reef squids may comprise a cryptic species complex. The species is likely to include several very similar and closely related species.
Amphioctopus fangsiao, called webfoot octopus, is a species of octopus, a cephalopod belonging to the genus Amphioctopus. It is found in the Pacific Ocean, including off the coasts of New Zealand as well as in the Yellow Sea and surrounding Chinese shores. It is also commercially fished.
Linckia multifora is a variously colored starfish in the family Ophidiasteridae that is found in the Indian Ocean and Red Sea. Its common names include the Dalmatian Linckia, mottled Linckia, spotted Linckia, multicolor sea star and multi-pore sea star.
Macrotritopus defilippi, commonly known as the Lilliput longarm octopus or the Atlantic longarm octopus, is a small species of octopus, a marine cephalopod mollusc of the order Octopoda.
Dipsastraea pallida is a species of colonial stony coral in the family Merulinidae. It is found in tropical waters of the Indian and Pacific Oceans. This is a common species of coral with a widespread distribution, and the main threat it faces is from the destruction of its coral reef habitats. It is rated as a "least-concern species" by the International Union for Conservation of Nature. This species was first described in 1846 as Favia pallida by the American zoologist James Dwight Dana; it was later transferred to the genus Dipsastraea, but some authorities continue to use the original name.
The larger Pacific striped octopus (LPSO), or Harlequin octopus, is a species of octopus known for its intelligence and gregarious nature. The species was first documented in the 1970s and, being fairly new to scientific observation, has yet to be scientifically described. Because of this, LPSO has no official scientific name. Unlike other octopus species which are normally solitary, the LPSO has been reported as forming groups of up to 40 individuals. While most octopuses are cannibalistic and have to exercise extreme caution while mating, these octopuses mate with their ventral sides touching, pressing their beaks and suckers together in an intimate embrace. The LPSO has presented many behaviors that differ from most species of octopus, including intimate mating behaviors, formation of social communities, unusual hunting behavior, and the ability to reproduce multiple times throughout their life. The LPSO has been found to favor the tropical waters of the Eastern Pacific.
