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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Epicarchesium

Epicarchesium Jankowski, 1985

Family Vorticellidae (ref. ID; 7114)
  1. Epicarchesium abrae (ref. ID; 7114)
  2. Epicarchesium granulatum (Kellicott, 1887) Jankowski, 1985 (ref. ID; 4613) reported author and year? (ref. ID; 2082)
  3. Epicarchesium pectinatum (Zacharias, 1897) (ref. ID; 4613 redescribed paper)
    Syn; Zoothamnium limneticum Svec, 1897 (ref. ID; 4613); Zoothamnium pectinatum Zacharias, 1897 (ref. ID; 4613)

Epicarchesium granulatum (Kellicott, 1887) Jankowski, 1985 (ref. ID; 4613) reported author and year? (ref. ID; 2082)

Descriptions

Two contractile vacuoles. (ref. ID; 2082)

Measurements

Silverlines from anterior end to aboral ciliary wreath (extremes 53-61, mean 57); silverlines from aboral ciliary wreath to scopula (extremes 27-34, mean 31); silverlines ratio 0.54. (ref. ID; 2082)

Epicarchesium pectinatum (Zacharias, 1897) (ref. ID; 4613 redescribed paper)

Synonym

Zoothamnium limneticum Svec, 1897 (ref. ID; 4613); Zoothamnium pectinatum Zacharias, 1897 (ref. ID; 4613)

Descriptions

1) Extended zooids in vivo 40-70 um, usually about 60 um long, approximately as wide as long. 2) Extended zooids conspicuously campanulate, usually nodding. Contracted specimens globular. 3) Macronucleus in longitudinal axis of cell, J-shaped. 4) Two contractile vacuoles at ventral wall of vestibulum; second vacuole overlooked by previous authors. 5) Pellicle with +/- conspicuous tubercles. A total of roughly 32 tubercle, that is, silverline mesh rows: about 18 mesh rows from anterior end to anlage of aboral ciliary wreath and about 14 from adoral ciliary wreath to scopula. 6) Oral apparatus occupies anterior end of cell, peristomial collar slightly projecting beyond body proper. Peristomial disc almost flat. Vestibulum of usual size, extends almost transversely to main body axis. 7) Stalk particularly branched, contractile due to distinct myonemes not fused at ramification sites, about 8 um across, surface smooth. 8) Colonies up to 1.36 mm long, consist of up to 70 zooids, fan-shaped when extended (not roundish in transverse view like Epistylis procumbens), globular when contracted. The main stalk, whose proximal portion curves like a crook, develops five lateral branches one after the other; the oldest branch detaches from the main stalk when four lateral offspring have been formed, leaving a wedge-shaped notch providing the main stalk with a highly characteristic pectinate (species name!) appearance. Euplanktonic, colonies usually swim with stalk directed forward. (ref. ID; 4613)

Comments

Packroff (1992) confirmed Kahl's (1935) observations that Zoothamnium pectinatum has a tuberculate pellicle and discontinuous stalk myonemes at the ramification sites. Thus, it has to be transferred to Epicarchesium Jankowski, 1985, a genus firmly established recently by Leitner & Foissner (1997). Easy to identify because of the planktonic habit and the conspicuous stalk notches. The type species of Epicarchesium, E. granulatum (Kellicott, 1887) Jankowski, 1985, is sessile. Epistylis procumbens, a colonial, planktonic peritrich too, has an acontractile stalk without myoneme and the zooids are usually distinctly larger (about 100 um) and thinner (2-2.5:1). Pelagic vorticellids (Pelagovorticella mayeri, P. natans) live solitarily. (ref. ID; 4613)