Fig. 1. The folium and its apertures. All specimens from the Gulf of Aqaba, Red Sea, Recent. SEM graphs. A-D: Rosalina bradyi (Cushman); A: detail of dissected specimen, oblique-ventral view. The approximate position of the breakage surface (arrows A-A) is indicated by the line A-A in Fig. B. B: ventral view showing the folium at its maximum development, with anterior and posterior apertures. C-D: peripheral and dorsal views. Note the restriction of the perforation to the dorsal surface of the shell, an indication that the face extends from the umbilical side of the shell over its periphery. E-H: Asterorotalia gaimardi (d'Orbigny). E-F: dissected specimens showing details of advanced umbilical architecture covered by the folia: foraminal and coverplates. G: oblique-ventral view showing the folia that cover the ventral part of the interlocular space. H: dorsal view showing the spiral arrangement of the chambers. a: aperture; ch: chamber lumen; cp: cover plate; f: foramen; fo: folium; foa: foliar aperture; fochl: foliar chamberlet lumen; fp: foraminal plate; is: interlocular space; li: lip (of foramen); n: notch; sf: septal flap; u: umbilicus; (Hottinger, 2006; fig. 53) CC/BY-NC-SA)
- according to Hottinger (2006):
FOLIAR CHAMBERLET - the part of a chamber delimited by a folium. A foliar chamberlet may be continuous with the main chamber, and is separated primarily (and partly or more completely) from the main chamber by a foramenal plate, by an umbilical plate, or - secondarily - by a cover plate or a sealing plate. A foliar chamberlet communicates with the exterior through foliar apertures and with the lumen of its own main chamber through openings in the umbilical plate or cover plate (when present) or at its margin. Depending upon the geometry of the test, a foliar chamberlet may be converted into part of a secondary spiral umbilical canal as part of the umbilical cavity and communicates with intraseptal interlocular spaces.
Hottinger (2006), Illustrated glossary of terms used in foraminiferal research. Carnets de Géologie, Memoir 2, ISSN 1634-0744
| Foraminifera | FORAM-Links | Contributors