Cyclical arrangement

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Fig. 1. Alternating arrangement of shell compartments in the three dimensions of space. Examples from Gulf of Aqaba, Red Sea; Recent. A-B: Alternating chamber arrangement in the linear dimension (= biserial arrangement) as in Textularia foliacea Heron-Allen et Earland, SEM and X-ray graphs of lateral view. C-D: Alternating chamberlet arrangement in the planar (second) dimension, as in annular-concentric, discoidal shell of Planorbulinella elatensis Thomas, SEM graph of lateral view and equatorial section in transmitted light microscopy, coloured. E: Stereograph showing alternating chamberlets of a main chamberlet layer, with main stolon axes (horizontal arrows) and retrovert stolons feeding lateral chamberlet (vertical arrows). Schematic, not to scale. F-G: Alternating chamberlet arrangement in the third dimension producing a chessboard pattern, as in the spherical-concentric, globular shell of Sphaerogypsina globulus (Reuss), SEM graph of external view and centered section in transmitted light micrograph, coloured. H: Stereograph showing alternating chamberlets forming chessboard pattern. Schematic, not to scale. Colours: red and blue: alternating generations of shell compartments; green: nepiontic, early stages including proloculus. a; aperture; ch: chamber lumen; chl: chamberlet lumen; f: foramen; lchl: lateral chamberlet lumen; (Hottinger, 2006; fig. 8 c-h [1] CC/BY-NC-SA)
Fig. 2. Chamber arrangement and apertural face. Schematic, not to scale. In part after Hottinger, 2000. 1: planispiral-spiroliniform. 2: planispiral-evolute and flaring, peneropliform. 3: planispiral-evolute, approaching reniform, 4: annular-concentric, with thickened and folded margins, as in Marginopora vertebralis. 5: planispiral-involute, as in Archaias. 6: biserial – textulariid. 7: biserial-cuneiform. 8: uniserial-conical. 9: uniserial-conical with marginal apertures. 10: streptospiral-involute as in Pseudonummuloculina. Coiling axis rotating with each chamber. 11: streptospiral with planispiral-involute adult stage, as in Helenalveolina. 12: planispiral involute. Coiling axis fixed throughout ontogeny. 13: planispiral-fusiform: A: axial section, E: equatorial section. Black arrow: direction of growth; white arrow: direction of movement. 14: miliolid (-quinquelocular, -trilocular), with fixed apertural axis and with coiling axis rotating in perpendicular position in respect to apertural axis. 15: miliolid-bilocular with fixed apertural and coiling axes. 16: unilocular-concentric, with discoidal trematophore, as in Lacazina elongata. 17: unilocular-concentric with annular trematophore, as in Lacazina compressa. 18: low-trochospiral, as in Rotorbinella. 19: high-trochospiral, as in Sakesaria; a: aperture; af: apertural face; apax: apertural axis; col: columella; fol: folium; ma: marginal aperture; n: notch; per: periphery; potort: polar torsion; pst: peristome; spax: coiling axis; (Hottinger, 2006; fig. 37 [2] CC/BY-NC-SA)


  • according to Hottinger (2006):

CYCLICAL ARRANGEMENT - arrangement of cyclical chamberlets in one plane or in concentric layers.


Hottinger (2006), Illustrated glossary of terms used in foraminiferal research. Carnets de Géologie, Memoir 2, ISSN 1634-0744

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