Canal systems

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Fig. 1. Canal systems. A: basic geometry of canals in simple rotaliid shells. Schematic, not to scale. Red: chamber plasm; yellow: canal plasm. B-C: during stages of retraction of the chamber plasm into the interior of the shell, the canal system provides motility to the organism by extruding the pseudopods through backdoors, so-called loop-holes. D-F: Challengerella bradyi Billman et alii. Gulf of Aqaba, Red Sea; Recent. SEM graphs. D: oblique-ventral view of umbilical face; E: dorsal (spiral) view; F: Epoxy resin cast of shell cavities showing canal system. G-H: Hottingerella chouberti (Hottinger), Northeastern Morocco, Lower Cretaceous. Schema after Hottinger, 1976, not to scale, and transmitted light micrographs. Note that the basic geometry with loop-holes in a shell lacking septal subdivision is similar to a rotaliid with chambers. a: aperture: ch: chamber; f: foramen; fol: folium; is: interlocular intraseptal space; isc: intraseptal canal; lh: loop-hole; m: mask; p: pores; rmfu: radial marginal furrows (open to the ambient environment for their full length prior to being covered by the next whorl); s: septum; sesut: septal sutures; sis: spiral interlocular space; spc: spiral canal; spmfu: spiral marginal furrow; spsut: spiral suture (between successive whorls); up: umbilical plate (general geometric position); vc: vertical canals (at umbilical chamber suture); x: approximate position of section; (Hottinger, 2006; fig. 26 [1] CC/BY-NC-SA)


  • according to Hottinger (2006):

CANAL SYSTEMS - a term collectively and broadly applied to those interconnected spaces of the foraminiferal test, that are primarily or secondarily separated from the main chamber lumina, but with which they may communicate in one or in successive whorls by openings other than intercameral foramina, the so-called loop-holes. Canal-systems contain functional microtubular ectoplasm and represent bypasses of spiral main chamber lumina so that ectoplasm deep inside the early parts of the test connects directly with extrathalamous rhizopodial ectoplasm. The spaces forming canal-systems are delimited by a number of discrete elements of the test: umbilical plate, cover plate joined to a foramenal plate, sealing plate, toothplate, septal flap, folia, previous coil, as well as by consecutive outer lamellae. See also: primary and secondary umbilical spiral canals; intraseptal interlocular space; grooves; enveloping canals; funnels; cord, crest.

See also


Hottinger (1967), Foraminifères imperforés du Mésozoïque marocain, Notes et Mémoires du Service géologique, Rabat, N° 209, p. 5-168

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

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