Brood chamber

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Fig. 1. Brood chambers in agamonts of (A-C) Sorites orbiculus (Forskal) and (D-E) Amphisorus hemprichii Ehrenberg, all from the Gulf of Aqaba. Recent. A: fresh hatching on empty mother shell under water. B: agamont shell, dried and split open in the equatorial plane. Some embryos remain in situ in the brood chambers. Note size of microspheric proloculus. SEM graph. C: detail of B showing embryo (consisting of proloculus and flexostyle) and surface of resorption including the organic lining. D: equatorial and E: axial sections showing an abrupt increase in the irregularity and volume of the chamberlet cavity in the last few chamberlet cycles (double arrows) marking the brood chambers. F: Neorotalia sp., thin section parallel to and near the axis of coiling, the last chamber filled with hatchlings. Transparent light micrograph. Spanish Pyrenees, Lower Eocene. G: Orbitolites sp. Oblique-centered thin section, transmitted light micrograph. Note the discrepancy between embryo size and brood chamberlet volumes: we are in presence of either a gamont producing small gametes or zygotes, or of a schizont keeping the offspring in regular broodchambers prior to the first, prolocular shell formation. Lowermost Eocene, Farafrah Oasis, Egypt. br: brood chamber; e: embryo; ol: organic lining; pr: proloculus; s: septum; (Hottinger, 2006; fig. 24 [1] CC/BY-NC-SA)

Definition

  • according to Hottinger (2006):

BROOD CHAMBER - chamber(s) or chamberlet cycle(s) with enlarged cavities that house the offspring before hatching. The enlarged chamber cavities may be produced by partial resorption of shell material, in particular of the endoskeleton and the septa. To date, brood chambers have been observed exclusively in agamonts (microspheric specimens).



See also:

References

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

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