Passion Flower Feather Star

Image: Richard Ling
Ptilometra australis

Oooooh!

Image: Richard Ling

Aaaaah!

Image: John Turnbull

How lovely!

The Passion Flower Feather Star is a Feather Star - a non-stalked Crinoid - found in shallow waters off south-east Australia.

Image: John Turnbull

Like other Crinoids they have a tiny, calcareous body called the calyx, which contains their organs but is utterly dwarfed by their long arms. In the case of the Passion Flower, there are about 20 of these arms and they reach a maximum length of about 8 cm (3 inches).

The spindly arms are covered in projections called pinnules which make the whole thing look like a big, bouquet of feathers. It'll probably be perched on a sponge because they need to get up into a current to feed.

Image: John Turnbull

Each pinnule is armed with tube feet that produce sticky mucus to catch tiny particles of food from the water. The food is then passed into a groove in the middle of the pinnule, where cilia pass it along into a groove in the middle of the arm so it can all move down into the mouth.

So those lovely feathers are basically conveyor belts covered in dirty mucus. Pretty ones, though!

Image: John Turnbull

The Passion Flower's pinnules are so dense and prickly that this harmless Crinoid looks a lot like the Crown of Thorns Starfish and its sharp, venomous stings.

Image: John Turnbull

When the Passion Flower gets tired from a hard day sitting around doing almost nothing at all, they can roll up their arms and take a rest. Now they look like a sea urchin!

They never look like a sea cucumber, though. One must maintain some standards.