Abdopus aculeatus

Abdopus aculeatus

''Abdopus aculeatus'' is a small octopus species in the order Octopoda. ''A. aculeatus'' has the common name of algae octopus due to its typical resting camouflage, which resembles a gastropod shell overgrown with algae. It is small in size with a mantle around the size of a small orange and legs 25 cm in length, and is adept at mimicking its surroundings.

Aculeatus has been described as "the only land octopus", because it lives on beaches, walking from one tidal pool to the next as it hunts for crabs. Many octopuses can crawl short distances on land when necessary, but no others choose routinely to do this.
Algae Octopus - Abdopus aculeatus As its name imply, the Algae Octopus - Abdopus aculeatus mimics the sea algae and sea weeds with appendages on its body and tentacles that gives them perfect camouflage.  They also takes on the colours of the algae/seaweed - brown, grey, white,green and purple. Abdopus aculeatus,Algae Octopus,Cebu,Geotagged,Malapascu,Octopus,Philippines,Winter

Behavior

Algae Octopuses are most active during the day, leaving their dens to forage and returning at night. In some areas , Algae Octopuses will forage among coral, but typically they do not. They tend to feed on small crustaceans including portunid and calappid crabs by groping and pouncing on small rocks and clusters of algae, and digging into the sand. They will chase their prey by jetting, the act of forcing water out of their siphon in order to propel their body forward, head first. Once they catch their prey they use their sharp beak to "drill" into its exoskeleton and reach the muscle within. Most often they will eat their prey on site, but on occasion when they consume their prey near their den, they will carry the exoskeleton up to a meter away to discard it.
Floating Pose This Octopus was seen during a night dive, on a sandy bottom.  It was posing and swaying its tentacles to make it looks like floating 'algae'.

Am not definitely sure this is an Algae Octopus - Abdopus aculeatus, I posted it to a Marine ID Forum, and was told it is likely an Algae Octopus. Abdopus aculeatus,Algae Octopus,Mabul,Malaysia,Octopus,Sabah

Habitat

The Algae Octopus is found throughout intertidal zones along the Indonesian, Philippine, and Northern Australian coastlines. They primarily live in areas with abundant sea grass coverage and occupy dens built into the sandy seafloor, which they line with small pebbles. In its resting camouflage, ''A. aculeatus'' displays mottled ochre, gray, and brown colors that resemble a shell overgrown with algae, and dark arm bars reminiscent of hermit crab legs.
Can you see me? An Algae Octopus - Abdopus aculeatus resting on the sea bottom, very well camouflage among the sandy/rocky bottom that was covered in dust particles (due to big waves during recent typhoon).

This is another picture of the same Octopus to see it more clearly :

https://www.jungledragon.com/image/65126/on_the_move.html Abdopus aculeatus,Algae Octopus,Anilao,Batangas,Octopus,Philippines

Food

Algae Octopuses are most active during the day, leaving their dens to forage and returning at night. In some areas , Algae Octopuses will forage among coral, but typically they do not. They tend to feed on small crustaceans including portunid and calappid crabs by groping and pouncing on small rocks and clusters of algae, and digging into the sand. They will chase their prey by jetting, the act of forcing water out of their siphon in order to propel their body forward, head first. Once they catch their prey they use their sharp beak to "drill" into its exoskeleton and reach the muscle within. Most often they will eat their prey on site, but on occasion when they consume their prey near their den, they will carry the exoskeleton up to a meter away to discard it.
On the move This Aglae Octopus - Abdopus aculeatus was on the move, allowing it to be seen more clearly.
Its body and tentacles are covered in 'fillaments' give it an appearance similar to algae, hence the name. Abdopus aculeatus,Algae Octopus,Anilao,Batangas,Octopus,Philippines

Evolution

''A. aculeatus'' demonstrates one of the most complex mating cultures of any documented octopus species. They participate in three distinct mating strategies: mate guarding, transient copulation, and sneaker mating. Larger males and females will have adjacent dens, where the male is able to extend his mating arm to the female's den, while resting in his own. These two individuals are paired and mate repeatedly for up to a week. However, the female does not remain monogamous to her mate, and may respond to sneaker mating from other males. In this instance, the guarding male may be present or away foraging, and a smaller male approaches the female’s den from an angle obstructed from the guarding male, sometimes camouflaged as a small female itself, to mate with the female. The third mating tactic is transient copulation, where a male will mate with an opportunistic female that he encounters while foraging. In all cases of successful copulation, the male uses the hectocotylus to transfer sperm packages to the female.
After successful mating, female will retreat to her den and cover the entrance with rubble. She remains in her den for several days, spawning multiple festoons equating to thousands of eggs. After spawning, she will remain with her eggs until they hatch, cleaning and caring for them. The hatchlings are planktonic and will not have parental protection after hatching, as algae octopuses are semelparous, dying shortly after their young are hatched. As the hatchlings grow larger, they remain in the intertidal zones and begin to burrow into the sandy bottom.

Juvenile and adult algae octopuses have a unique method of locomotion. In addition to the common tactics of swimming, crawling and jetting, algae octopuses participate in upright, bi-pedal locomotion. This is a fast method of movement used for escape and often paired with crypsis, or camouflage to mimic surrounding sea grass.

''Octopus bimaculoides'' may be a closely related species, as the two share many skin components that are the basis for their camouflage tactics, though this may also be evidence of evolutionary convergence.

References:

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Taxonomy
KingdomAnimalia
DivisionMollusca
ClassCephalopoda
OrderOctopoda
FamilyOctopodidae
GenusAbdopus
SpeciesA. aculeatus