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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Pseudobalanion

Pseudobalanion Foissner, Oleksiv & Muller, 1990 (ref. ID; 4785 original paper)

[ref. ID; 1046]
The genus Pseudobalanion in several aspects resembles the genus Balanion (Wulff, 1916). However, according to Small and Lynn (1985), Balanion is characterzied by brosse kinetids internal to the oral dikinetids. In Pseudobalanion, a brosse is absent; thus, its probably belongs to the Holophryidae. (ref. ID; 1046)

[ref. ID; 4785]
Type species; Pseudobalanion planctonicum (ref. ID; 4785)
  1. Pseudobalanion planctonicum Foissner, Oleksiv & Muller, 1990 (ref. ID; 1046, 4785 original paper) reported author and year? (ref. ID; 191)
    See; Balanion planctonicum (ref. ID; 4611, 4613)

Pseudobalanion planctonicum Foissner, Oleksiv & Muller, 1990 (ref. ID; 1046, 4785 original paper) reported author and year? (ref. ID; 191)

See

Balanion planctonicum (ref. ID; 4611, 4613)

Descriptions

The description given by Foissner et al. (1990 see: ref ID; 4785) is briefly summarized. Pseudobalanion planctonicum is a small bursiform ciliate with its anterior end transverse truncated. The circular oral area is nearly as wide as the body and surrounded by finger-like flaps. The circumoral kinety is composed of dikinetids. Somatic kineties are arranged meridionally and are posteriorly shortened. A single long caudal cilium originates from the posterior pole. The nuclear apparatus is located centrally, with the spherical micronucleus near the slightly ellipsoid macronucleus. No extrusomes can be seen in vivo; with protargol-staining, dark rods, presumably toxicysts, become visible in the cytoplasm and especially in the flaps of the oral apparatus. The division axis during morphogenesis is oblique. (ref. ID; 1046)
[Swimming behaviour]: Swimming behaviour of P. planctonicum, as observed in well-fed cultures, was charaterized by alternation of rather slow motion (velocities similar to those of Rhodomonas) with sudden speeding in a straight line. This behaviour is distinctly different from the rapid circling movement characteristic for small Urotricha species and, therefore, can be used to distinguish between the two genera at low magnification. Occasionally, however, circling movements were also observed in P. planctonicum, as a reaction to mechanical disturbance or in starving cultures. (ref. ID; 1046)

Measurements

Cell volume in P. planctonicum varies widely with nutritional state. While the smallest individuals are only slightly larger than their prey, some specimens contained up to eight ingested Rhodomonas cells. In 60 individuals which were selected at random from field samples over 3 months (February to April 1987) I recorded a mean body length of 14.6+/-2.5 um (range 10.2-21.7 um) and a mean cell volume of 1328+/-711 um3 (range 311-3564 um3). Mean and range of cell size were similar in field and cultured material. (ref. ID; 1046)