Epiderm

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Fig. 1. Alveolar exoskeleton and polygonal network. A-C: simple alveolar layer in Everticyclammina virguliana (Koechlin), Mechra Klila, Northeastern Morocco, Uppermost Jurassic. A: stereograph, schematic, not to scale. B: tangential section. Note the large size of the alveoles in a postseptal position. C: para-equatorial, non-centered section showing septa and the basal coat at the bottom of the chamber, resembling a basal layer. E-G: polygonal network in Spirocyclinidae. E: Choffatella tingitana Hottinger, megalospheric generation, in tangential section near to the equatorial plane. Note the clear differentiation of beams and rafters. D: stereograph of spirocyclinid polygonal network. Note the curved pigeon holes in preseptal position which in axial section might be mistaken for foramina. F-G: extension of beams into a corrugated sheet that replaces endoskeletal pillars in Hottingertidae. F: stereograph representing a part of an axial section. Not to scale. G: Alveosepta powersi (Redmond), Northeastern Morocco, Upper Jurassic. Equatorial section of megalospheric specimen. alv: alveoles; b: beam; bl: basal layer; corr: corrugated median extension of beams; f: foramen; ph: pigeon holes; s: septum; sf: supplementary foramina; sph: sphaeroconch; ssut: septal suture. Arrows: direction of growth. After Hottinger, 1967.; (Hottinger, 2006; fig. 45 [1] CC/BY-NC-SA)

Definition

  • according to Hottinger (2006):

EPIDERM - the thin, outermost coat of a foraminiferal non-lamellar, imperforate chamber wall if it differs in texture from that of the inner layers. Present in all exoskeletons consisting of a polygonal network as in orbitolinids (s.str.) and spirocyclinids. May be homologous with the tectum of fusulinids.

See also

References

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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