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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ptychocylis

Ptychocylis Brandt, 1896 (ref. ID; 3607, 7037)

Order Heterotrichida Stein, 1867: Suborder Tintinnoinea Kofoid & Campbell, 1929: Family Ptychocylidae Kofoid & Campbell, 1929 (ref. ID; 3607)

[ref. ID; 3596]
Lorica bell-shaped with two suboral expansions; oral rim usually denticulate with numerous minute triangular teeth; aboral region with or without an aboral cone or horn; aboral end rounded or acute; wall composed of incompletely separated lamellae, generally thickened at the suboral bulge and the aboral end; surface usually ornamented with a fine polygonal reticulation. (ref. ID; 3596)

[ref. ID; 7037]
Kofoid & Campbell (1929) listed and illustrated 12 species of the genus Ptychocylis, 10 of which were from the North Atlantic and the Arctic. The 10 non-Pacific species were recognized also by Marshall (1969), who made no additions or deletions from Kofoid & Campbell's list. Schulz & Wulff (1929) discussed the great variability of lorica shape in the genus. These authors have produced outline drawings of 109 specimens. (ref. ID; 7037)
  1. Ptychocylis acuta Brandt, 1906 (ref. ID; 7037) reported year? (ref. ID; 3596, 3607)
  2. Ptychocylis ampla Meunier, 1910
    See; Ptychocylis obtusa (ref. ID; 3607)
  3. Ptychocylis arctica Brandt, 1906 (ref. ID; 7037) reported year? (ref. ID; 3596)
  4. Ptychocylis basicurvata Meunier, 1910 (ref. ID; 7037) reported year? (ref. ID; 3596)
  5. Ptychocylis cylindrica Meunier, 1910 (ref. ID; 7037)
  6. Ptychocylis drygalskii Brandt, 1896 (ref. ID; 3606) or 1906 (ref. ID; 7037) reported year? (ref. ID; 3596, 3607)
    Syn; Ptychocylis obtusa var. drygalskyi (part) Brandt, 1906 (ref. ID; 3606); Ptychocylis urnula var. digitalis Jorgensen, 1901 (ref. ID; 3606); Ptychocylis urnula var. digitalis f. subintegerrima Jorgensen, 1901 (ref. ID; 3606); Ptychocylis ventricosa Meunier, 1910 (ref. ID; 3606)
  7. Ptychocylis drygalskii Meunier, 1910
    See; Ptychocylis obtusa (ref. ID; 3607)
  8. Ptychocylis duplicata Meunier, 1910
    See; Ptychocylis obtusa (ref. ID; 3607)
  9. Ptychocylis glacialis (ref. ID; 7037)
  10. Ptychocylis humilis Hada, 1937 (ref. ID; 3596 original paper)
  11. Ptychocylis media Meunier, 1910
    See; Ptychocylis obtusa (ref. ID; 3607)
  12. Ptychocylis minor (Jorgensen, 1900) (ref. ID; 7037) reported author and year? (ref. ID; 6971, 6973)
    Syn; Jorgensen's P. urnula var. beta minor in Jorgensen 1899 (ref. ID; 7037)
  13. Ptychocylis obtusa Brandt, 1896 (ref. ID; 3596, 3606, 3607) or 1906 (ref. ID; 7037) reported year? (ref. ID; 3772)
    Syn; Ptychocylis ampla Meunier, 1910 (ref. ID; 3607); Ptychocylis drygalskii Meunier, 1910 (ref. ID; 3607); Ptychocylis duplicata Meunier, 1910 (ref. ID; 3607); Ptychocylis media Meunier, 1910 (ref. ID; 3607); Ptychocylis urnula var. obtusa Jorgensen, 1901 (ref. ID; 3607)
  14. Ptychocylis obtusa var. drygalskyi (part) Brandt, 1906
    See; Ptychocylis drygalskii (ref. ID; 3606)
  15. Ptychocylis ostenfeldi Kofoid & Campbell, 1929 (ref. ID; 7037)
  16. Ptychocylis urnula (Claparede & Lachmann, 1858) (ref. ID; 1868)
  17. Ptychocylis urnula var. digitalis Jorgensen, 1901
    See; Ptychocylis drygalskii (ref. ID; 3606)
  18. Ptychocylis urnula var. digitalis f. subintegerrima Jorgensen, 1901
    See; Ptychocylis drygalskii (ref. ID; 3606)
  19. Ptychocylis urnula var. obtusa Jorgensen, 1901
    See; Ptychocylis obtusa (ref. ID; 3607)
  20. Ptychocylis ventricosa Meunier, 1910
    See; Ptychocylis drygalskii (ref. ID; 3606)

Ptychocylis acuta Brandt, 1906 (ref. ID; 7037) reported year? (ref. ID; 3596, 3607)

Descriptions

Lorica elongate bell-shaped, its length 2.1 oral diameter; oral rim denticulated with numerous teeth (over 40); first suboral bulge 1.07-1.13 oral diameters in transdiameter, usually a little smaller than but rarely equal to the second in diameter; bowl below the posterior expansion slightly narrowing (13-23 degrees); aboral region tapering (57-75 degrees) gradually into an aboral cone with a blunt apical tip, occasionally concave conical; wall thin, thickened a the aboral end, where reticulation is coarse. (ref. ID; 3596)

Comments

Dimensions of lorica of specimens from Akkeshi Bay are smaller on the average as compared with those of the Davis Straits which are 120-145 um long and 75-82 um broad. The length of the lorica is generally variable in proportion to the aboral cone which is variable in form. A specimen provided with an apical spine at the aboral end was exceptionally observed in the collection taken on May 19, 1934. The species differs from P. obtusa Brandt in its slender contour, the thinner wall, and the conical posterior region of the bowl. (ref. ID; 3596)

Measurements

Length 115 (100-134); oral diameter 61 (58-68); diameter of the anterior expansion 68 (64-78) um. (ref. ID; 3596)

Ptychocylis arctica Brandt, 1906 (ref. ID; 7037) reported year? (ref. ID; 3596)

Descriptions

Lorica tall sac-shaped, 1.5 oral diameter in length, having two elevated bands, anterior and posterior respectively existing around the upper 0.07 and 0.27 of the total length; aboral region nearly hemispherical; aboral end more or less flattened without an aboral conel wall thin. (ref. ID; 3596)

Comments

The species differs from P. basicurvata Meunier in the flat aboral end. P. basicurvata has a lorica nearly straight on the sides and hemispherical in the aboral region. (ref. ID; 3596)

Measurements

Length 87; oral diameter 58 um. (ref. ID; 3596)

Ptychocylis drygalskii Brandt 1896 (ref. ID; 3606) or 1906 (ref. ID; 7037) reported year? (ref. ID; 3596, 3607)

Synonym

Ptychocylis obtusa var. drygalskyi (part) Brandt, 1906 (ref. ID; 3606); Ptychocylis urnula var. digitalis Jorgensen, 1901 (ref. ID; 3606); Ptychocylis urnula var. digitalis f. subintegerrima Jorgensen, 1901 (ref. ID; 3606); Ptychocylis ventricosa Meunier, 1910 (ref. ID; 3606)

Descriptions

Lorica stout, 1.4-1.5 oral diameters in length; oral rim more or less constricted with a minute dentation; anterior expansions 1.1-1.2 oral diameters in diameter, equal or scarcely larger than the posterior, each situated along the suboral 0.07 and 0.35 of the lorica; bowl somewhat constricted (15-35 degrees) below the promedian bulge; aboral region abruptly conical, gradually terminating to a low aboral cone; aboral end broadly rounded; wall thickened. (ref. ID; 3596)
Lorica wide goblet-shaped, 1.4 oral diameters in length; oral rim regularly denticulated; bowl generally a low, inverted, convex cone with two distinct expansions: each respectively 1.15 and 1.20 oral diameters in transdiameter; aboral region concave conical 90 degrees; aboral end broadly rounded, more or less thicker than other parts, with a rugose surface. (ref. ID; 3606)

Comments

The size of the lorica and the form of the aboral region are slightly variable. The species differs from P. obtusa Brandt in dimension and proportion besides the shape of the posterior half of the lorica. (ref. ID; 3596)
Differs from Ptychocylis obtusa Brandt in stouter proportions and in the shape of the aboral cone. (ref. ID; 3606)

Measurements

Length 72 (65-77); oral diameter 50 (48-52); diameter of the anterior expansion 60 (56-61) um. (ref. ID; 3596)
Length 77; oral diameter 55 um. (ref. ID; 3606)

Ptychocylis humilis Hada, 1937 (ref. ID; 3596 original paper)

Descriptions

Lorica low bell-shaped with two suboral bulges, its length 1.07-1.15 oral diameters; oral margin erected, denticulated with numerous triangular teeth; first and second bulges located respectively in the anterior 0.1 and 0.3 of the total length, former usually a little wider in diameter than the latter, its diameter 1.05 oral diameter; bowl conical (32-37 degrees) in the middle; aboral region broadly conical (82-90 degrees), provided with a low aboral cone, its height 0.1 of the total length; wall thin, scarcely separated in the widened portions, reticulation of the surface most marked in the aboral end. (ref. ID; 3596)

Comments

Specimens figured by Brandt (1906) in Pl.55, figs.1,2 from the former two localities above mentioned, have an aboral region somewhat concave and an aboral cone imperfectly developed, but specimens from Akkeshi Bay have a convex aboral region and a distinct cone. The species differs from P. drygalskii Brandt in the larger size, the thin wall, and the erect oral rim. (ref. ID; 3596)

Type locality

The species was first reported from the western area of Spitzbergen and afterwards off the Norwegian Coast and the Strait of Georgia, Canada. (ref. ID; 3596)

Measurements

Length 82-105; oral diameter 76-91 um. (ref. ID; 3596)

Ptychocylis obtusa Brandt, 1896 (ref. ID; 3596, 3606, 3607) or 1906 (ref. ID; 7037) reported year? (ref. ID; 3772)

Synonym

Ptychocylis ampla Meunier, 1910 (ref. ID; 3607); Ptychocylis drygalskii Meunier, 1910 (ref. ID; 3607); Ptychocylis duplicata Meunier, 1910 (ref. ID; 3607); Ptychocylis media Meunier, 1910 (ref. ID; 3607); Ptychocylis urnula var. obtusa Jorgensen, 1901 (ref. ID; 3607)

Descriptions

Lorica goblet-shaped, 1.55-1.75 oral diameters in length, oral margin minutely dentate; two suboral elevated bands nearly equal in diameter, its transdiameter 1.15-1.25 oral diameters; aboral region convex conical (95-120 degrees) with a marked aboral cone of which length 0.1-0.2 of the total length; wall thickened. (ref. ID; 3596)
Lorica stout bell-shaped, 1.50-1.85 oral diameters in length; oral rim denticulate; bowl contracting very slightly towards the aboral end, with two anterior expansions and a very weakly developed aboral dilation; posterior region abruptly conical (90-102 degrees), with an inverted truncated cone (27-40 degrees) as long as 0.15-0.20 of the total length in length; wall rugged in the aboral end, 0.045 oral diameters in thickness. (ref. ID; 3607)

Comments

An individual variation in seen in shape and height of the aboral cone which is narrow and tall in some specimens, but wide and low in others. The species differs from P. drygalskii Brandt in its greater length and having the differentiated aboral cone, and from P. acuta Brandt in the stouter form, the rounded aboral region, and the broad aboral cone. (ref. ID; 3596)
Differs from Ptychocylis acuta Brandt in stouter proportions and in the broadly rounded aboral end and from P. drygalskii Brandt in the shape of the aboral region having a definite aboral cone. (ref. ID; 3607)

Measurements

Length 105 (100-125); oral diameter 65 (60-67) um. (ref. ID; 3596)
Length 98 (97-112); oral diameter 63 (60-71) um. (ref. ID; 3606)
Length 108 (91-120); oral diameter 63 (60-71) um. (ref. ID; 3607)