Collotheca pelagica Rousselet 1893
Collotheca pelagica, a pelagic swimming rotifer with a mucilaginous sheath.
Collotheca pelagica, another specimen with amictic egg.
Collotheca pelagica; the males are distinctly smaller than the females and are mobile, they swim much faster than the females and have eyespots. F: foot; Pe: ciliated penis. (1)
Collotheca pelagica; the mucilaginous sheath offers space for all kinds of epibiontic organisms, usually bacteria. The sheath of this specimen is covered with zooflagellates. (2)
Collotheca pelagica; lateral view of a specimen with slightly contracted corona (caused by vibrations of the camera shutter due to immersion of the 63x/1,4 planapo oil objective), so it is not possible to say where the trochus ends and the vestibulum (V) begins. The prey (small flagellates) is transported to the proventriculus (PV) via an oscillating epipharyngeal system consisting of a ciliated membrane which seems to be enforced by a clasp (or maybe the clasp is only the optical transect of the ciliated membrane) (both inside the white circle). The ciliated membrane looks like the one from the terminal ciliated cells of the nephridial system, for example Asplanchna priodonta. The beating frequency is about 1,5-2 Hz. This system must not be confused with the mastax (Mx) which is located at the end (functionally), i.e. on the left side of the proventriculus in this image. From a video the "chewing frequency" of the mastax could be calculated to 0.5 Hz, so the two systems seem to be not synchronized. In contrast to the liquid in the vestibulum the content of the proventriculus is slightly brownish suggesting that there are already digesting processes going on in the proventriculus. St.:stomach; In: intestinum; Eg: amictic egg; MC: motile cilia; CR: ciliary row. (3)
Collotheca pelagica; detail of the epipharyngeal system (the view is turned approx. 55 degrees countercclockwise compared to the above image). CM: ciliary membrane; CR ciliary row; PV: proventriculus; V: vestibulum.
Collotheca pelagica; video of the epipharyngeal system >>>>>>
Location: Maastricht, NL, Monseigneur Nolenspark, pond (1); Hattingen Felderbachtal, pond (2; Ohligser Heide, Teich (3)
Habitat: Plankton (1,2,3)
Date: 8.10.2011 (1); 20.09.2014 (2); 18.08.2015 (3)
freshwater life
marine life