Choma

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Fig. 1. Chomata. A-C: Eowedekindellina sp. Permian, Iran, Allemann collection, oblique, subaxial and subequatorial sections, transmitted light micrographs, and model. Note poleward extension of chomata forming a basal layer. D-F: ordinary chomata in Triticites sp., equatorial and axial sections, transmitted light micrographs and model. Lower Permian, Spitzbergen. Note in D the sector-wise appearance and disappearance of the chomata due to the slight obliquity of the section. ath: antetheca; c: choma; c*: cutoff choma stressing the uncertainty about the connection between the choma and the antetheca; fl: fluted septa; kth: keriotheca; s: septum; sp: septal pores; spth: spirotheca; t: tunnel; (Hottinger, 2006; fig. 31 [1] CC/BY-NC-SA)

Definition

  • according to Hottinger (2006):

CHOMA - (pl. chomata; German: Basalreifen); a dense deposit on previous whorl constituting the chamber floor, and in fusulinids forming a pair of parallel ridges, each extending from a tunnel margin to the previous one. May extend progressively polewards over the entire chamber floor in staffellids, much like a basal layer in fusiform porcelaneous shells.







References

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

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