Red-spot 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: Callistoctopus Iw. Taki, 1964

Species: Callistoctopus dierythraeus Norman, 1993

Species Description:

Large and muscular species. Arms are 4 to 5 times longer than mantle length. Dorsal arms are longer than ventral arms (1>2>3>4) with moderate depth of webs around 18 to 28 % of arm length. Web is deepest on dorsal arms and shallowest between ventral arms. Two rows of suckers on each arm. In larger animals, around 200 to 280 suckers on each normal arm. Enlarged suckers absent. Right third arm of males hectocotylized, around 75% length of opposite arm. Ligula cylindrical and muscular, around 6% of arm length. Calamus small, around 15% of ligula length. Hectocotylized arm with 103 to 125 suckers. The resting color pattern is red with numerous white and dark spots scattered all over dorsal and lateral surfaces. Alarm color pattern of white background with numerous large red spots on dorsal and lateral surfaces. False-eye spots (ocelli) absent. Sculpture: Skin texture of scattered rounded papillae over smooth skin. Papillae located in centres of spots. Single, slightly larger papilla over each eye, surrounded by low punctae. Skin ridge absent around lateral margin of mantle.

Synonyms:

Octopus dierythraeus Norman, 1993

Other Records(References):

Callistoctopus dierythraeus Norman 1993- [Norman & Hochberg (2005): 127-154;Jereb et al (2014): 99]

Global Distribution:

Northern and northeast Australia from Great Barrier Reef to northwest Western Australia

Remarks:

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


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