Encentrum gulo Wulfert, 1936- a "killer" rotifer
Encentrum gulo is a carnivorous rotifer. (This species has been erroneously misidentified as Encentrum lutra before in this website, but E. lutra is reported not to be a predator of rotifers). Constantly the environment is searched for prey with hectic back and forth movements of the head region. Every few seconds the trophi are ejected (a behavior common with other Encentrum species, see image here) like a stiletto, which may cause injuries of the potential prey. In this image the left arrow points to the head cirri and the right arrowhead to the toes (in optical cross-section) of an engulfed rotifer (Bryceella stylata). (2)
Encentrum gulo while swallowing the Brycella stylata of the image above. This image was taken approx. 7 minutes befor the upper image. The arrows mark some of the nuclei of the germovitellarium of the prey.
Encentrum gulo: another specimen from the same sample, with ingested Cephalodella rotifer (23.02.2013). Arrow: trophi (left ) and toes (right) of the prey. (2)
Encentrum gulo: potential prey is grasped with the tweezer-like trophi and dragged into the mouth. Ciliates were treated in different ways: Blepharisma hyalinum was never attacked even if E. lutra touched it. Frontonia however was attacked, but not succesfully: I could watch such attacks: Frontonia ejected its extrusomes (upper right corner of the image) and managed to escape, thereby loosing a lot of the cytoplasm. E. gulo was obviously affected by the trichocysts: the head was retracted several times after the ciliate´s defense what looked like a dog having caught a hedgehog. (2)
Encentrum gulo: forcipate trophi (2) with relative short intramallei; inner margins of the rami are smooth; rami length / width ≤1.4; fulcrum short (≤ 1/2 of manubrium length); outer outline of rami convex; rami with 2-3 terminal teeth. In contrast to Encentrum lutra and Encentrum orthodactylum the supramanubria are very thin. (3)
Encentrum gulo: arrowhead points to the lemon-shaped gastric glands. This species has a small foot and very short toes. (16.2.2013) (3)
Encentrum gulo: another specimen; the arrowhead points to the lemon-shaped gastric glands (23.2.2013)
Location (1): Hattingen Oberstueter, forest (2,3);
Habitat (1): tree moss (2,3); (click image to enlarge >>>)
Date: 23.02.2013 (2) ; 16.2.2013 (3);
freshwater life
marine life