White-spotted octopus
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White-spotted octopus ( Callistoctopus macropus ) |
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| ( Risso , 1826) |
The white-spotted octopus ( Callistoctopus macropus ) is a large cephalopod from the genus Callistoctopus . It was first described by Joseph Antoine Risso in 1826 .
features
anatomy
The white-spotted octopus is a muscular species with an elongated shape. The shape of the mantle varies and is elongated to ovoid. In the back half the body is wider. It can weigh up to two kilos. The males have a coat length of 15 centimeters and reach a total length of 1.5 meters.
The arms reach seven times the length of the coat. The tentacles are of different lengths. The dorsal arms are the longest and most robust. The white-spotted octopus has two rows of suction cups . The suction cups on the dorsal arms are larger than on the remaining tentacles and reach up to 13.5% of the length of the mantle. There is no noticeable difference between males and females in terms of the length of the arms and the size of the suction cups.
In the male Callistoctopus macropus , the third right arm forms the hectocotylus . This is significantly shorter than the rest of the tentacles. It is between 41 and 51 percent of the length of an average arm. A small to medium At the top Ligula that 4.5-8% of the arm length reached. It is narrow and pointed with puffy edges. The spermatophore groove has numerous sensitive transverse lamellae. The calmus reaches 13–18% of the ligular length. The terminal organ, the actual penis, is comparatively small at 12–28% of the mantle length. It is covered with large forward or backward facing diverticula .
The velar skin of the white-spotted octopus is poorly developed and reaches a maximum of 7–17% of the arm's length. An ink bag is provided. The gills have ten to eleven lamellae per demibranch . The funnel organ has a W-shaped appearance, the lateral fold being shorter than the medial fold. The radula consists of seven transverse rows of teeth and marginal plates. The middle tooth, called rachis , forms a large Mesocone and two to three page spikes on each side, the asymmetrical structure.
Appearance
The skin color of living animals at rest is brick red or brownish with different patterns. The body has numerous white spots on the back, arms, coat and head. Like all real octopuses, Callistoctopus macropus can adapt its appearance to its surroundings. This camouflage is based on a combination of different chromatophores and a change in the texture of the skin.
The skin is smooth. There are large wart-like structures called papillae above each eye.
distribution and habitat
The distribution area of the white-spotted octopus extends over all coasts of the Mediterranean and the Atlantic coast to Dakar in Senegal . It is a benthone species and lives in warm, temperate waters. At depths between 5 and 100 meters below sea level. The preferred habitat is sand, gravel and sea grass meadows. Callistoctopus macropus often buries itself in the sand.
Way of life
nutrition
Callistoctopus macropus is a nocturnal hunter. A hunting method often observed is moving from one coral bush to the next. He wraps his coat around one end of the branches and uses his arms to examine the interior of the coral bushes for invertebrates and small fish that are hiding there. Corals of the genera Acropora and Stylophora are preferred . Different species of grouper and other predatory fish can associate with the white-spotted octopus. They eat the small organisms that are washed out of the coral.
Reproduction
The male spermatophores reach around 50% of the mantle length. The mature egg cells are 2.5 millimeters long. The female produces short-stemmed eggs that are 1.2–4 millimeters in size. The eggs are laid in an arch on a hard surface. The female hatches the offspring, ensures good ventilation of the eggs and keeps them clean. During the breeding season, the female completely stops eating. Shortly after the eggs hatch, the female dies. The planktonic living larvae have a size of 5.5 millimeters and seven short arms after hatching. They feed on zooplankton .
fishing
Despite its size, there are no commercial catch statistics for the white-spotted octopus. In the Mediterranean, however, it is very likely that Callistoctopus macropus accounts for a small proportion of the catch statistics for Octopus vulgaris .
Web links
Individual evidence
- ↑ a b c d e Cephalopods of the world. An annotated and illustrated catalog of cephalopod species known to date (p. 106)
- ↑ a b c Callistoctopus macropus (sealifebase)
- ↑ a b c Marine Invertebrates of Bermuda - Octopus macropus ( Memento of the original from January 19, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Skin as superreflectors
- ↑ Octopodidae - Article at Tree of Life
- ↑ a b Diamant, Ariel; Shpigel, Mucky: Interspecific feeding associations of groupers (Teleostei: Serranidae) with octopuses and moray eels in the Gulf of Eilat (Agaba) . In: Environmental Biology of Fishes . 13, No. 2, 1995, pp. 153-159. doi : 10.1007 / BF00002584 .
- ↑ a b Boletsky, Sigurd v .; Fuentès, Michael; Offner, Nicolas: First record of spawning and embryonic development in Octopus macropus (Mollusca: Cephalopoda) . In: Journal of the Marine Biological Association of the UK . 81, No. 4, 2001, pp. 703-704. doi : 10.1017 / S002531540100443X .
