The Variable spiny starfish (Coscinasterias tenuispina) is called this because instead of the classic five arms it usually has seven. It is therefore an exception regarding the classic five-ray symmetry of echinoderms. Furthermore, as can be seen in this specimen, three of the seven arms are very small and are therefore slowly growing back. ...

Martasteria or Thorny starfish (Marthasterias glacialis Linnaeus, 1758) is one of the most common starfish in the Mediterranean Sea, it is an echinoderm of the Asteriidae family. In this video we see it lying on a cliff that varies from 41 to 49 meters deep, rich in red Gorgonians of the Paramuricea clavata species and the classic yellow sponges of the Verongia species, therefore a guaranteed show of colors at the expense, however, of the visibility of the water about two or three meters. ...

The Martasteria or Spiny Starfish, Marthasterias glacialis, is an echinoderm of the Asteriidae family common in the Mediterranean Sea. Also called a Tank star, due to the characteristic plates bristling with thorns that distinguish it from other starfish, it has a regular shape with five arms. The body is characterized by spines of variable color: white, gray, brown, red, blue. It appears to be the largest species in the Mediterranean, capable of reaching even 85 centimeters in diameter.

The Basket Star is characterized by five tentacles, each branched several times, with which it clings to the branches of the soft corals and which are opened at night to feed on. The body has a diameter that can reach 8 centimeters, with the complete opening of the tentacles the maximum width of the entire animal can reach 80 centimeters. It feeds passively with the open tentacles, in particular of planktonic microparticles.

I did the underwater video in a stretch of sea between Livorno and the island of Gorgona at a depth of over 50 meters. I was surprised to meet so many sea urchins, known as Stylocidaris affinis, ...