The starfishes belong to the echinoderms family (like sea urchins, sea cucumbers…), who unlike the rest of the animals, can change, voluntary the flexibility of their conjunctive tissue.The change is as important as the one that exists between the ice and the water. The conjunctive tissue can be rigid or flexible, depending on the will of the animal and of the environment.
The most known characteristic about the echinoderms is their pentaradially symmetry. That means, in general, that the body is divided in five parts, around a backbone. Echinoderm means "animals with thorny skin".
Approximately 1500 species of starfishes are known. They are cosmopolitan animals that generally live in shallow waters, move upon the rocks of the sea bed, or live buried in the sandy bottom. Normally the starfishes are red, orange, blue or purple, or show combinations of these colours.
The mouth is in the centre of the ventral surface of the body, called disc. Each of the arms presents two to four rows of small tubular appendices, named tube feet. They are filled with a liquid based on sea water and works like an hydraulic system. Generally, the starfishes move slowly and are able to flip over if they accidentally fall upside down. At the end of each arm we can find a small tube foot, in the shape of tentacle, which have a sensory function.
The majority of the starfishes is carnivorous, and feeds on other echinoderms, all kinds of invertebrates especially snails, bivalve, crustacean, and even on small fish.
To feed, the star wraps her arms around the prey. Some of them can evert out their stomach and introduce it through small openings no bigger than 0,1mm. Others swallow entirely their prey.
The Asteroidea (starfishes) own a great power of regeneration. Any part of the arms can be regenerated, also if the body is partially damaged. The regeneration speed is slow and needs generally over one year to be completed.
In general, the sexes are separated, the fertilization is external and the first part of the life take place as plancton, floating in the water column.
The brittle stars are a special echinoderms class: the Ophiuroidea. They look likes sea stars since they present arms to, but in other aspects both classes are not similar. The Ophiuroidea (picture 9 and 10) represents the echinoderm group with the major evolutionary success. This success is probably in relation with their mobility, diversity of food habits and their small size, which allows them to explore inaccessible places for the majority of the echinoderms.
Names of several starfish species that I can see during my dives in Tenerife:
1: Coscinasterias tenuispina
2: Astropecten aranciacus
3: Ophidiaster ophidianus
4: Narcissia canariensis
5: Hacelia attenuata
6: Echinaster sepositus
7: Kind Luidia. This specie is currently on study. It is asked to report to the Museum of Natural Sciences of Tenerife any if you see one in the Canary Islands.
8: Marthasterias glacialis
9: Ophioderma longicaudum
10: Antedon bifida
The starfishes, among others, play an important role in the sea urchin diaderma antillarum population regulation and control because they are its predators. It is very important not to re-collect starfishes and not to buy any for ornamental purposes or acuariofilia.
Here is a short video where you can see a sea star hunting sea urchins:
The most known characteristic about the echinoderms is their pentaradially symmetry. That means, in general, that the body is divided in five parts, around a backbone. Echinoderm means "animals with thorny skin".
Approximately 1500 species of starfishes are known. They are cosmopolitan animals that generally live in shallow waters, move upon the rocks of the sea bed, or live buried in the sandy bottom. Normally the starfishes are red, orange, blue or purple, or show combinations of these colours.
The mouth is in the centre of the ventral surface of the body, called disc. Each of the arms presents two to four rows of small tubular appendices, named tube feet. They are filled with a liquid based on sea water and works like an hydraulic system. Generally, the starfishes move slowly and are able to flip over if they accidentally fall upside down. At the end of each arm we can find a small tube foot, in the shape of tentacle, which have a sensory function.
The majority of the starfishes is carnivorous, and feeds on other echinoderms, all kinds of invertebrates especially snails, bivalve, crustacean, and even on small fish.To feed, the star wraps her arms around the prey. Some of them can evert out their stomach and introduce it through small openings no bigger than 0,1mm. Others swallow entirely their prey.
The Asteroidea (starfishes) own a great power of regeneration. Any part of the arms can be regenerated, also if the body is partially damaged. The regeneration speed is slow and needs generally over one year to be completed.
In general, the sexes are separated, the fertilization is external and the first part of the life take place as plancton, floating in the water column.
The brittle stars are a special echinoderms class: the Ophiuroidea. They look likes sea stars since they present arms to, but in other aspects both classes are not similar. The Ophiuroidea (picture 9 and 10) represents the echinoderm group with the major evolutionary success. This success is probably in relation with their mobility, diversity of food habits and their small size, which allows them to explore inaccessible places for the majority of the echinoderms.
Names of several starfish species that I can see during my dives in Tenerife:1: Coscinasterias tenuispina
2: Astropecten aranciacus
3: Ophidiaster ophidianus
4: Narcissia canariensis
5: Hacelia attenuata
6: Echinaster sepositus
7: Kind Luidia. This specie is currently on study. It is asked to report to the Museum of Natural Sciences of Tenerife any if you see one in the Canary Islands.8: Marthasterias glacialis
9: Ophioderma longicaudum
10: Antedon bifida
The starfishes, among others, play an important role in the sea urchin diaderma antillarum population regulation and control because they are its predators. It is very important not to re-collect starfishes and not to buy any for ornamental purposes or acuariofilia.Here is a short video where you can see a sea star hunting sea urchins:
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