In modern Indo-Pacific coral-reef areas, the porcela- neous larger foraminifera Alveolinella quoyi and Borelis schlumbergeri, the only extant prolate ellipsoidal alveolinoids, live on sandy and coral-rubble substrates. Apertural features are functional elements of shell morphology; therefore, speci- mens were investigated to assess these characters. The primary apertures of these alveolinoid forms can be obstructed by two different masks (mineralized infraskeletal shell elements): si- nusoidal reverse masks (pending from the upper border of the aperture) and upright (rising from the lower border). Alveolinella quoyi exhibits sinusoidal reverse masks, whereas Borelis schlumbergeri has upright masks. These masks consist of discrete groups of needle-shaped crystals. The reverse masks are part of the apertural rim, whereas the upright masks form from the basal layer. These ephemeral characters occur at the terminal stage of the formation of the apertural face and are resorbed after the calcification of the new chamber. These features, with no or very low fossilization potential, appear to reflect distinct functions during chamber growth. The extruding protoplasm from the reverse-mask and upright mask-bearing apertures enhances shell stabilization. In the poles, where the reverse masks and upright masks do not occur, the protoplasm likely enables motility.
Ephemeral masks in the ellipsoidal foraminifera Alveolinella and Borelis (Alveolinoidea). Resilient solutions to stabilization in coral-reef settings / Bassi, Davide; Pignatti, Johannes; Abramovich, Sigal; Fujita, Kazuhiko; Hohenegger, Johann; Lipps, Jere H.; Iryu, Yasufumi. - In: JOURNAL OF FORAMINIFERAL RESEARCH. - ISSN 1943-264X. - 52:2(2022), pp. 92-98. [10.2113/gsjfr.52.2.92]
Ephemeral masks in the ellipsoidal foraminifera Alveolinella and Borelis (Alveolinoidea). Resilient solutions to stabilization in coral-reef settings
Johannes Pignatti;
2022
Abstract
In modern Indo-Pacific coral-reef areas, the porcela- neous larger foraminifera Alveolinella quoyi and Borelis schlumbergeri, the only extant prolate ellipsoidal alveolinoids, live on sandy and coral-rubble substrates. Apertural features are functional elements of shell morphology; therefore, speci- mens were investigated to assess these characters. The primary apertures of these alveolinoid forms can be obstructed by two different masks (mineralized infraskeletal shell elements): si- nusoidal reverse masks (pending from the upper border of the aperture) and upright (rising from the lower border). Alveolinella quoyi exhibits sinusoidal reverse masks, whereas Borelis schlumbergeri has upright masks. These masks consist of discrete groups of needle-shaped crystals. The reverse masks are part of the apertural rim, whereas the upright masks form from the basal layer. These ephemeral characters occur at the terminal stage of the formation of the apertural face and are resorbed after the calcification of the new chamber. These features, with no or very low fossilization potential, appear to reflect distinct functions during chamber growth. The extruding protoplasm from the reverse-mask and upright mask-bearing apertures enhances shell stabilization. In the poles, where the reverse masks and upright masks do not occur, the protoplasm likely enables motility.File | Dimensione | Formato | |
---|---|---|---|
Bassi_Ephemeral_2022.pdf
solo gestori archivio
Tipologia:
Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza:
Tutti i diritti riservati (All rights reserved)
Dimensione
1.34 MB
Formato
Adobe PDF
|
1.34 MB | Adobe PDF | Contatta l'autore |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.