Scientific name: Prostheceraeus roseus

Lang, 1884

Common Name: Cat: Planària rosa, Cast: Planaria rosa, Ang: Pink flatworm, Fr: Ver plat rose, Ale: Rosa Plattwurm

Family: Worms - Flatworms

Area type: None in particular

Depth: Between 5 and 50m

Measures: Up to 3cm

How does it look like?
This flatworm achieves a size of 2-3cm. The bodyshape is oval and very flat. At the head they have two tentacles formed by the animals own body edge. The colour is pink with a central longitudinal white band and a dozen of fine white stripes. The body margin has also a white band.

Where does it live?
They live usually on rocks, vertical walls and on calcareous seaweeds, sponges, bryozoans or sea squirts. They can be normally found in depths between 5 and 40-50 meters.

How does it feed?
Flatworms are carnivorous. All of them have predilection for sedentary and colonial animals like bryozoans, cnidarians, sea squirts, molluscs and some crustaceans or tube worms. Prostheceraeus roseus seems to feed on sea squirts of the Pycnoclavella group.

How do they reproduce?
Reproduction seems to take place in summer. Each animal has both genders, but usually they reproduce with another specimen. They prick their pin-formed penis through their couple’s skin to exchange their sperm. Eggs are laid isolatedly.

Is a confusion possible?
Usually there’s a confusion with Prostheceraeus giesbrechtii, because of the missing red colour tones underwater. Human’s eyes are cheated, not beeing able to distinguish between pink and blue. Errors and confusions are also common in scientific literature. There also haven’t been many studies about.

Curiosities
·Did you know that flatworms survive in very variable conditions, but if their subsistence is in risk they are able to split in two, regenerating each part a complete animal?

·They detect food at great distances, thanks to smell cells on their head.
·They wrap their preys up with a slimy secretion which leaves them motionless. Afterwards they push their pharynx out of their mouth, secreting enzymes which predigest their food. Finally they sip their preys.

Taxonomy
Filum: Platyhelminthes, Subfilum: Turbellaria, Infrafilum: Rhabditophora, Order: Polycladida, Suborder: Cotylea, Family: Euryleptidae, Genus: Prostheceraeus.