Plastogamy

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Fig. 1. Faces (coloured red) in biserial and spiral forms. SEM graphs (if not specified otherwise) of specimens from the Gulf of Aqaba, Red Sea. Recent. A-C: Textularia aff. goesi Cushman, apertural and lateral views of intact specimens and frontal view of broken specimen showing septal face. Note the smooth surfaces characteristic of the faces of many agglutinated forms. D-E: Discorbinoides sp. A in Hottinger et alii, 1993. Plastogamic pair and plastogamic umbilical face with radial grooves. F-G: Glabratellina sp. A in Hottinger et alii, 1993. Ventral view showing plastogamic ventral face with radial grooves and lateral view showing shell whorls with their sutures. H-I: Bolivinella elegans Parr, a lamellar-perforate, biserial form with known plastogamic reproduction, that has radial grooves on its face. J: Floresina spicata (Cushman et Parker) has a smooth face with few radial grooves and in addition grooved septal sutures. A (plastogamic?) plate covers the narrow umbilicus. As yet, plastogamy has not been observed in vivo in this species. K-L: Amphistegina lobifera Larsen, Megalospheric specimen in incident light micrograph, ventral view and detail of apertural face. Note the extension of the ornamented surface for a notable distance over peripheral-ventral parts of the previous whorl. M-N: Amphistegina bicirculata Larsen, megalospheric specimen in incident light micrograph, ventral view and detail of apertural face. Note comparatively much smaller ornamented surface corresponding to lower water energy in its deeper habitat. a: aperture; af: apertural face; f: foramen; p: pore; plp: plastogamous (?) plate; pp: parapore; rgr: (plastogamous) radial grooves; sfa: septal face; stch: stellar chamberlet; stsut: stellar suture; sut: (chamber) suture; wsut: whorl suture; (Hottinger, 2006; fig. 48 [1] CC/BY-NC-SA)



Definition

  • according to Hottinger (2006):

PLASTOGAMY - two gamonts form a pair by joining their faces and exchanging gametes within a common shell lumen where fecundation takes place. Zygotes are hatched from the paired shells to form an agamont embryo. The mother shells are then discarded (see Erskian & Lipps, 1987). The faces of the shells are decorated by numerous rows of small pustules (costellae) in a radial pattern independent of the chamber arrangement.



See also:


References

Erskian & Lipps (1987), Population dynamics of the foraminiferan Glabratella ornatissima (Cushman) in Northern California, Journal of foraminiferal Research, Lawrence, vol. 17, N° 3, p. 240-256.

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



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