Maori octopus
| Macroctopus maorum | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Order: | Octopoda |
| Family: | Octopodidae |
| Genus: | Macroctopus |
| Species: | M. maorum |
| Binomial name | |
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Macroctopus maorum (Hutton, 1880) |
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| Synonyms | |
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Macroctopus maorum is known more commonly as the Maori octopus or the New Zealand octopus (wheke in Maori). They can also be known as Pinnoctopus cordiformis, is found in the waters around New Zealand and southern Australia.M. maorum is one of the largest and most aggressive octopus species living in the New Zealand and Australian waters. They feed mainly on crustaceans and fish, although they have a short life span the females lay thousands of eggs and are very protective of their eggs.
Macroctopus maorum is a large octopus and it is regularly described as a ‘robust’ species, it is a member of the Octopus macropus species complex. The morphological traits characteristic of this complex are a high number of gill lamellae, a robust conical copulatory organ and arms of varying length with long unequal dorsal arms generally four to six times longer than the mantle. Although being unequal, their arms are said to be long and evenly tapering and Macroctopus maorum are even known to regrow arms when one has been lost. Being the largest member of its complex arm span is said to exceed 3 metres (9.8 ft). They have four to six suckers on the first and second arm pairs which are usually about 40 millimetres (1.6 in) in size. Suckers are arranged in two rows down the arm length, there is thought to be no correlation between sexes and size of suckers however there was an increase in sucker size with body mass increase. Coloration of this species can vary Macroctopus maorum can be distinguished from other species by the colour, they will be either orange-brown or dark purple-grey. The octopus has numerous small iridescent white spots on the web, arms and dorsal arm crown but there are no spots present on the mantle.Macroctopus maorum has 12–14 gill lamella per demibranch, the mantle is described as broadly ovoid and exhibits a skin pattern of longitudinal ridges. Along the dorsum there are five rows of unbranched papillae and two more papillae appear individually above the eyes. Octopus papillae are camouflage specialised with the ability to change shape, such as by extending in and out from the body. Male M. maorum have a small ligula, the ligula is a specialised arm tip on the hectocotylized arm which grips to allow the transfer of spermatophores. Within the complex O. macropus, Macroctopus maorum is thought to be the largest member. In a study estimating M. maorum size based on a sample of 90 beaks, the largest individual found had a body length of 2.0 metres (6 ft 7 in) and body mass of 12 kg. Macroctopus maorum has an upper beak and lower beak, the upper beak can be used to differentiate Macroctopus maorum and Enteroctpus zealandicus as it has a lack of overlap in the ratio of upper hood length and upper chest length. Macroctopus maorum hatchlings are usually about 5.06 in size, they have 7–8 suckers per arm and each dorsal arm will have 6–11 chromatophores.
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Wikipedia