Ron's Critter of the Day

TAXONOMY
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Family: Octopodidae.

Genus/species: Amphioctopus marginatus

GENERAL CHARACTERISTICS
The main body (mantle) is small to medium-sized, 5–8 cm (15 cm [6 in] including arms) in length. The arms are usually dark with contrasting white suckers. They have only soft bodies with no internal skeleton with a hard parrot-like beak allowing them to hide in very small spaces.

DISTRIBUTION/HABITAT
The tropical western Pacific and coastal waters of the Indian Ocean on sandy bottoms.

DIET: Shrimp, crabs, and clams. A.marginatus uses its sharp parrot-like beak to crush the shells of its prey. Shells of prey that are difficult to pull or bite open can be “drilled” in order to gain access to the soft tissue: salivary secretions soften the shell, and a tiny hole is created with the radula (a rasp-like structure of tiny teeth used for scraping food particles off a surface). The octopus then secretes a toxin that paralyzes the prey and begins to dissolve it. The shell is pulled apart and the soft tissues are consumed.

REPRODUCTION: Octopus reproduction strategy provides a counterpoint to the male sacrifice of the flower mantis and the bird-eater tarantula,  The coconut octopus female mates with the male, and retreats into a den where she lays her eggs. At this point, she no longer feeds, instead spending the rest of her now short life protecting her eggs from predators and continually cleaning and aerating them.  She dies shortly after the hatching of her eggs and their subsequent entry into the plankton.

Egg mass below

MORTALITY/LONGEVITY:  10–12 months

REMARKS: The species’ common name derives from this octopus’ habit of carrying around coconut shell halves, by fitting its body into the bowl and extending rigid arms from the coconut’s edge to the substrate and tiptoeing away in gait called “stilt-walking”  or bipedal walking.    

Below A. marginatus using a shell. 

The Steinhart is the first public aquarium in the U.S. to display the coconut octopus.  Our octopus was collected by Bart Shepherd, Curator of the Steinhart Aquarium, during a 2011 research expedition to the Philippines.

flickr  http://www.flickr.com/photos/cas_docents/6776485376/in/set-72157608597736188

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