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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Campascus

Campascus Leidy, 1877 (ref. ID; 4910)

Phylum Rhizopoda: Class Filosea: Subclass Testaceafilosia: Family, Psammonobiotidae: some authors would place this class in the Phylum Cercozoa, but this position is not yet universally accepted. (ref. ID; 4910)

(ref. ID; 1618]
Test retort-shaped with curved neck, rounded triangular in cross-section; aperture circular, oblique, with a thin transparent discoid collar; nucleus large; one or more contractile vacuoles; body does not fill the test; fresh water. (ref. ID; 1618)

[ref. ID; 1923]
Shell retort-shaped. Scales very minute, giving a punctate appearance and eventually with foreign elements. Neck with a delicate, transparent disc-shaped collar, perpendicular to the aperture. (ref. ID; 1923)

[ref. ID; 3686]
Shell colourless or yellow; retort-shaped and oval in transverse section; composed of circular siliceous shell-plates; aperture terminal circular bordered by a thin, transparent disc-like collar. (ref. ID; 3686)

[ref. ID; 4910]
The genus Campuscus was erected by Leidy (1877) to accommodate a testate rhizopod with filose pseudopodia and "a pair of lateral divergent processes to the fundus" of the test. The basic shape of the Campascus test resembles that of Cyphoderia. Its structure, however, consisting of a homogeneous chitinoid membrane with scattered "sand" (exogenous) particles and an oral aperture "surrounded with a delicate, structureless membranous zone" (Leidy 1877, 1879) was sufficiently different from that of Cyphoderia (covered with endogenously produced scales and lacking the oral membrane) to warrant separate genus status. Unfortunately, C. cornutus has never been seen since Leidy's original discovery of specimens from China Lake in Wyoming. (ref. ID; 4910)
Type species; Campascus cornutus Leidy (ref. ID; 4910)
  1. Campascus bidens Krascheninnikov, 1923 (ref. ID; 4910)
  2. Campascus cornutus Leidy (ref. ID; 1618, 1923, 3693)
  3. Campascus cyphoderiformis Chardez, 1984 (ref. ID; 2151 original paper)
  4. Campascus dentatus Edmondson & Kingman, 1913 (ref. ID; 4910)
  5. Campascus interstitialis Golemansky, 1981 (ref. ID; 3519)
  6. Campascus minutus Penard, 1899 (ref. ID; 1923, 2441, 3173, 4910) reported year? (ref. ID; 3693)
  7. Campascus simcoei Nicholls, 2003 (ref. ID; 4910 original paper)
  8. Campascus triqueter Penard, 1891 (ref. ID; 2441) reported year? (ref. ID; 3693)
  9. Campascus vulgaris Valkanov, 1936 (ref. ID; 2425)

Campascus cornutus Leidy (ref. ID; 1618, 1923, 3693)

Descriptions

Test pale-yellow retort-form; with a covering of small sand particles; triangular in cross-section; a single nucleus and contractile vacuole; filopodia straight; in the ooze of mountain lakes. (ref. ID; 1618)
Shell transverse section trigonal with rounded angles; lateral processes developed from the fundus. Plates small, round more or less covered by foreign particles. In common with Cyphoderia, the body of all species of Campascus enclose minute yellow or brown granules (pheosomes) very resistant of reagents, C. cornutus is a rare species inhabiting the ooze of lakes. (ref. ID; 1923)

Measurements

110-140 um long, aperture 24-28 um in diameter. (ref. ID; 1618)
Length 112-140 um. (ref. ID; 1923)

Campascus minutus Penard, 1899 (ref. ID; 1923, 2441, 3173, 4910) reported year? (ref. ID; 3693)

Descriptions

A minute form; retort-shaped, without processes. (ref. ID; 1923)
Typical shape of the test of C. minutus in lateral view was generally elliptical in outline with a curved neck and a slightly flared collar surrounding the anterior oral aperture, and often included a slightly lobed posterior. Less commonly encountered were those with distinctly pointed or rounded posteriors. In ventral view the test outline a typically elliptical to slightly rhomboidal. Tests were wider than high and had a broadly rounded triangular shape in optical transverse sections. Overall median test length, width height and aperture diameter of 64, 34, 29 and 17 um, respectively, were calculated (n=36). Considerable range in size and shape of the test of this species was encountered, however. Among the atypical shapes found were those with narrow, elongate tests, those with very wide tests and those with truncate posteriors. Reproduction was sometimes encoutered, but the evidence (two tests joined at their oral apertures) could not be used to determine if it was sexual or asexual, because the high optical density of the test obscured detail of the nuclei in these specimens. Tests were covered with variously-shaped particles, apparently of exogenous origin (as determined from the irregularity of the shapes of included particles and from the occasional occurrence of diatom frustule fragments). Shapes of particles included circles, ellipses, squares, oblong rectangles and polygons; all were intricately arranged with little overlap and minimal spacing between particles, reminiscent of a flagstone patio. Most common particle sizes were 1-3 um on the longest dimension. (ref. ID; 4910)

Measurements

Length 50-60 um. (ref. ID; 1923)

Campascus simcoei Nicholls, 2003 (ref. ID; 4910 original paper)

Diagnosis

Protoplast is Cyphoderia-like, with long, branching, filose pseudopods and included numerous, small spherical reddish-orange refractive bodies ("phaeosomes") scattered throughout the cytoplasm. Test is covered with small, mainly angular, polymorphic and flat particles. Test shape is bulbous with a rounded posterior with from 1-5 (but may be absent) short, curved "horns" covered with smaller particles. Smaller particles also cover the test in the region of the oral aperture. The anterior of the test is strongly arched so that the circular oral aperture opens on a plane that is nearly parallel to that of the long axis of the test. Surrounding the oral aperture, there is a short, slightly flared membranous collar, devoid of adhering particles. (ref. ID; 4910)

Etymology

The specific epithet (simcoei) is after Lake Simcoe, where the first specimens of this species were found. (ref. ID; 4910)

Type locality

Littoral zone (sand bottom) of Sibbald Point Provincial Park, Lake Simcoe, Ontario, Canada (44 degrees 18'N; 79 degrees 18'W). (ref. ID; 4910)

Type specimen

The type specimen, mounted in Canada Balsam on a glass slide, was deposited with the Canadian Museum of Nature (Ottawa, Ontario, Canada) under catalogue No. CMNI-2002-0002. (ref. ID; 4910)
[Holotype material]: Retained by the author in sample No. V-1525, collected October 27, 2001. (ref. ID; 4910)

Measurements

Total test length (including posterior horns) is 94-115 um; test width in ventral view is 52-68 um; test height in lateral view is 44-62 um, and aperture diameter (including collar) is 22-27 um (n=16). (ref. ID; 4910)