Coconut Octopus

Class: Cephalopoda

Family: Octopodidae

Family Description:

This family contains the vast majority of octopuses, with more than 200 valid species. They are bottom-living, muscular animals with eight arms. Each arm possesses 1 or 2 rows of suckers. All species lack fins and rows of cirri adjacent to suckers. The internal shell is reduced to a pair of small rod-like stylets or is absent. One arm of the third arm pair (typically right-hand side) is modified in mature males (known as the hectocotylized arm). This arm bears a gutter-like groove (spermatophore groove) along the ventral margin of the arm and a modified arm tip (ligula) used to grip and pass spermatophores to the female. A funnel locking apparatus is absent.

Genus: Amphioctopus P. Fischer, 1882

Species: Amphioctopus marginatus Iw. Taki, 1964

Species Description:

Robust species and moderate size. The species arms are 2 to 3 times longer than mantle length. Lateral arms longest (typically 3>4=2>1) than dorsal arms. Webs on lateral arms deepest approximately 30% of total arm length, however, webs between dorsal arms much shallower and web margins extend at least halfway along arms. Two rows of suckers on each arm and 4 to 5 larger suckers present in mature males on arms 2 and 3, respectively. Right third arm of males hectocotylized, length around 80% of opposite arm. Calamus well developed, around 50% of ligula length. Hectocotylized arm with 60 to 80 suckers. Body coloration is from orange brown to purple background with dark purple brown reticulations defining distinct patches in irregular longitudinal rows. Meanwhile, the colors of suckers along arms (dark brown) are white to pink. False-eye spots (ocelli) absent on the species and white triangle shape spotted below each eyes. Dark vein-like patterns on lateral arm located in the same position as false eyespots in ocellate species. A pair of white spots situated on dorsal mantle, slightly from anterior to midpoint of mantle. Diamond shape of longitudinal skin ridges present on the dorsal mantle.

Synonyms:

Octopus marginatus Taki, 1964; Octopus striolatus Dong, 1976.

Other Records(References):

Amphioctopus marginatus Iw. Taki, 1964- [Jereb et al. (2014): 75-76]

Global Distribution:

Found in tropical continental waters of the Indian Ocean, from Durban, South Africa, to Red Sea, India, south-east Asia, Taiwan (Province of China), Philippines and Japan, as well as east to north-eastern Australia

Remarks:

This taxon has not yet been assessed for the IUCN Red List


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