Octopus Diagram – Classification and Morphology

Octopuses belong to the class Cephalopoda, characterized by their soft bodies, eight arms, and distinct head. They lack a skeleton and possess a beak-like mouth, large eyes, and a highly developed nervous system. Octopuses possess remarkable camouflage abilities and can change colour and texture to blend with their surroundings. They are skilled predators, using their tentacles to capture prey and their beak-like mouths to consume it, often feeding on crustaceans, fish, and molluscs.

In this article, we will study the taxonomic classification of the octopus, its habitat, diagram, anatomy, and reproduction of an octopus, behaviour, and intelligence.

An octopus is a marine mollusk belonging to the class Cephalopoda, characterized by its soft, boneless body and eight long tentacles. Octopuses lack a skeleton and possess a beak-like mouth, large eyes, and highly developed nervous system. They are known for their remarkable camouflage abilities and skilled hunting techniques, using their arms to capture and manipulate prey. With complex brains capable of problem-solving and learning, octopuses are considered highly intelligent invertebrates.

The largest known octopus species is the Giant Pacific Octopus (Enteroctopus dofleini) which can be around 5m tall while the smallest ones are O. arborescens that reach a length of about 5 cm only. Octopuses have a short life span that ranges between a few months to around 5 years and varies from species to species. Some species of Octopuses are also served as food in various cuisines.

Below is a labelled diagram of octopus:

Below is the taxonomic classification of an Octopus:

Octopuses are highly adaptable and live in a variety of marine environments, ranging from shallow coastal waters to deep regions of the ocean. Factors such as food availability, the presence of predators, and suitable locations for reproduction and shelter influence their choice of habitat. Some examples include:

• The California two-spot octopus (Octopus bimaculoides) is often found in reef environments along the California coast, where it can hide among rocks and crevices.
• The common octopus (Octopus vulgaris) is known to inhabit shallow coastal waters, including rocky shores and sandy bottoms, where it can prey on crustaceans and small fish.
• The dumbo octopus (Grimpoteuthis species) is a deep-sea octopus found in abyssal plains and other deep-sea environments.
• The blanket octopus (Tremoctopus) is a pelagic octopus that is found in open ocean waters.
• The sand octopus (Octopus kaurna) is adapted to sandy substrates and can bury itself in the sand for camouflage and hunting.

Octopuses have a bilaterally symmetrical soft body well adapted to ensure their survival in the complex marine habitat. Some key morphological feature of Octopuses are given below:

Head and Body

• Octopuses have a distinct head, which contain their brain, eyes, beak, and mouthparts.
• Their body, known as the mantle, is soft and muscular, containing vital organs such as the gills, digestive system, and reproductive organs.

Arms

• Octopuses possess eight arms, each lined with two rows of suction cups, known as cirri.
• These arms are highly flexible and prehensile, allowing octopuses to grasp and manipulate objects with precision.
• The arms contain no skeletal structure, consisting primarily of muscle and connective tissue.

Suckers

• The suction cups on an octopus’s arms are equipped with chitinous rings and a central cavity connected to a muscle.
• Suckers are used for locomotion, prey capture, and exploration of the environment.
• Each sucker can exert a powerful grip, enabling octopuses to hold onto prey and objects with remarkable strength.

Mantle and Fins

• The mantle is the main body cavity of the octopus, containing internal organs and providing propulsion through jet propulsion.
• In some species, fins or flaps may extend from the mantle, helping in maneuverability and steering during swimming.

Skin and Coloration

• Octopus skin is soft, flexible, and covered in chromatophores, pigment-containing cells that allow for rapid color change and camouflage.
• They can change color, texture, and even body shape to blend seamlessly with their surroundings, providing effective camouflage from predators and prey alike.

Eyes

• Octopuses possess complex camera-type eyes, which are well-developed and highly efficient for detecting light and formulating images.
• Their eyes exhibit adaptations for underwater vision, including a large pupil, a cornea that adjusts for underwater refraction, and a highly sensitive retina.

Beak and Mouthparts

• The beak of an octopus is made of chitin and is located at the center of its arms.
• It serves as a powerful tool for breaking apart prey and tearing flesh.
• Octopuses also possess a radula, a rasping tongue-like structure equipped with rows of small, chitinous teeth used for scraping and manipulating food.

Reproduction in octopuses is a complex process involving distinct mating behaviors, reproductive anatomy, and life cycle stages.

1. Sexual Dimorphism: Octopuses exhibit sexual dimorphism, with males smaller and possessing a modified arm called a hectocotylus used for transferring sperm to the female during mating.
2. Mating Behavior: Mating in octopuses often involves elaborate courtship rituals, where males display colorful body patterns and perform visual signals to attract females. Once a male successfully courts a receptive female, he uses his hectocotylus to transfer spermatophores (sperm packets) into the female’s mantle cavity.
3. Internal Fertilization: After mating, the female stores the sperm in a specialized cavity called the seminal receptacle until she is ready to fertilize her eggs. Fertilization is internal, occurring inside the female’s body.
4. Egg-Laying: Female octopuses lay hundreds to thousands of small, transparent eggs in protected locations such as rock crevices or dens. The female carefully tends to the eggs, cleaning them and aerating them by gently fanning them with her arms to ensure proper oxygenation.
5. Brooding Period: During the brooding period, which can last from a few weeks to several months depending on the species, the female remains vigilant over her eggs, guarding them against predators and keeping them clean. She may refrain from feeding during this time and may even engage in self-sacrificial behavior to ensure the survival of her offspring.
6. Hatching: Once the eggs hatch, the young octopuses, known as hatchlings or juveniles, emerge from the egg capsules and begin their independent lives. They are fully formed miniature versions of adult octopuses and must fend for themselves from the moment of hatching.
7. Short Lifespan: Octopuses have relatively short lifespans, with most species living for only a few years. This limited lifespan, coupled with the solitary nature of octopuses and high levels of predation, underscores the importance of successful reproduction for the survival of the species.

Octopuses possess a highly developed nervous system with a centralised brain. They exhibit complex behaviours, problem-solving skills, and learning capabilities. For example, some of the species, like veined octopuses, can manipulate objects like coconut shells as portable shelters and arrange stones to create defence barriers.

Octopuses also exhibit excellent memory and learning skills. Studies suggest that octopuses can remember individuals and adjust behaviours according to their learnings from past experiences. Several instances have been reported where octopuses have escaped complex setups like aquariums. 

Some interesting facts about octopuses are listed below:

• Octopuses sense and taste through their suckers.
• Octopuses have remarkable regenerative abilities.
• Octopuses have three hearts. Two hearts pump blood to the gills, where it is oxygenated, while the third heart pumps the oxygenated blood to the rest of the body.

Octopuses are interesting eight armed cephalopods that are considered to be the most intelligent invertebrates. They inhabit a large variety of marine environment and exhibit remarkable adaptability. They reproduce only once in their life time and generally die after their eggs hatch. They are well known for their speed and vision which makes them good hunters. Octopuses have the remarkable color changing abilities which is used by them to camouflage, communicate, and even in expressing their emotions.

Also Read:

• Morphology and Anatomy of Frog
• Morphology of Earthworm
• Morphology of Cockroach

How many Hearts does an Octopus have?

An octopus has three hearts. Two of these hearts pump blood to the gills and the third one pumps blood from gill to the other parts of the body.

What Order does the Octopus Belong to?

The octopus belongs to the order Octopoda within the class Cephalopoda.

What is the Classification of Octopuses?

Octopuses are classified under the phylum Mollusca, class Cephalopoda, and order Octopoda.

Does Octopus have Teeth?

No, octopus do not have teeth. They have radula. It is a hard structure inside the mouth that helps in cutting and grinding.

What are the Morphological Characteristics of Octopus?

The morphological characteristics of octopuses include a soft body with a mantle, eight flexible arms with suckers, a bulbous head with large eyes, and chromatophores for camouflage.

Are Octopus Friendly to Humans?

Octopuses have not been reported to be very social or friendly with humans. However, they have been reported to exhibit conditional bonding like curiosity on seeing a human and acting playful, certain level of interactivity with their caretakers when fed.

What makes Octopus Special?

Well developed nervous system, intelligence, excellent problem solving ability, camouflaging, mimicry, and defense mechanisms make octopuses special.

Why is it called an Octopus?

It is called an octopus because it has eight long arms. In Greek “oktō,” means “eight,” and “pous,” means “foot” or “leg.” Thus, the word octopus means eight legs.