Stentor (protozoa)

Stentor roeseli with perlschnurförmigem macronucleus

The trumpet animals ( Stentor roeseli ) are a genus usually tightly living ciliates.

Features

Trumpet animals are among the largest single-celled organisms and are up to 2 mm long. Take in the extended condition to a funnel - up trumpet shape. The front end carries the often occupied with spirally arranged eyelashes mouth ( cytostome ), is very wide. After the rear, the cell body narrows gradually to a thin stem with the stuck trumpet animals at the base. The rear end can get stuck in a secluded himself from the animal cover. Through this sheath several individuals can be colony -connected with each other.

Contractile structures inside the cell allow the trumpet animals to flexibly change their shape. They appear often oval elongated.

You may like Stentor roeseli appear colorless or colored blue as the Blue Trumpet animals ( Stentor coeruleus ) or green as the Green Trumpet animals ( Stentor polymorphus ). The green color is produced by symbiotic algae.

Characteristic of the trumpet animals is a composite of several knot-like sections, perlschnurförmiger macronucleus.

Stentor sp.

Way of life

Trumpet animals are found only in freshwater. Mostly, they sit with their pointed end of the body on the ground, such as on the underside of leaves or duckweed on Myriophyllum, and swirls with the help of her lash bacteria from which they feed mainly, to the cytostome. You may detach from the substrate and swim with the help of cilia around to establish himself again at a new location.

Preferably in the spring it sometimes leads to a mass development of free-floating specimens of Stentor coeruleus in lakes. The animals then can unite at the water surface to " sooty " areas and thus provide a form of water bloom. The probable cause of this phenomenon is the common grazing on the surface floating accumulations of tree pollen, because there were such " Rußflächen " more often observed with an inch- wide yellow margin.

System

The Heterotrichea, which include the trumpet creatures that have long been found in the group of Spirotrichea. Recent research has shown, however, that they are not closely related to the other groups of Spirotrichea. In particular, the division of the macronucleus by external microtubules has meant that they are now placed as a sub- class in the subphylum Postciliodesmatophora.