Difference between revisions of "Endoskeleton"

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==Definition==

*''according to Hottinger (2006):''

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'''ENDOSKELETON''' - localized thickenings on the inner surface of the chamber wall that partly or totally subdivide the main chamber lumen in the lee of protoplasmic streams according to a pattern produced by the arrangement of intercameral foramina in successive septa. Plate-like elements ([[septula]]), usually perpendicular to the septum, may form more or less complete partitions touching the lateral walls or fusing with elements of the [[exoskeleton]]. Discontinuous, columnar partitions are called [[pillars]] (or interseptal pillars). A third type of endoskeleton is produced by layers of shell deposited on the chamber floor and coating the previously exposed outer shell surface completely ([[basal layer]]) or partially ([[chomata]] and [[parachomata]] of fusulinids). In different taxa, the three endoskeletal types may occur alone or in varying combinations~~. Fig. 47 & Fig. 63~~ . Often, endoskeletal elements appear only in the course of ontogeny, usually later than exoskeletal elements. In agglutinated shells endoskeletal elements include the septum and may be recognized by remarkably coarse and irregularly shaped particles that obscure the genetically fixed pattern in contrast to the more ordered exoskeletal elements of the same specimen. Whether the toothplates and their equivalents in lamellar perforate foraminifera and the secondary septa produced by folds of the inner lamella in orthophragminid lamellar architecture are homologous equivalents of the endoskeletal structures of non-lamellar-imperforate foraminifera remains an open question.

+

'''ENDOSKELETON''' - localized thickenings on the inner surface of the chamber wall that partly or totally subdivide the main chamber lumen in the lee of protoplasmic streams according to a pattern produced by the arrangement of intercameral foramina in successive septa. Plate-like elements ([[septula]]), usually perpendicular to the septum, may form more or less complete partitions touching the lateral walls or fusing with elements of the [[exoskeleton]]. Discontinuous, columnar partitions are called [[pillars]] (or interseptal pillars). A third type of endoskeleton is produced by layers of shell deposited on the chamber floor and coating the previously exposed outer shell surface completely ([[basal layer]]) or partially ([[chomata]] and [[parachomata]] of fusulinids). In different taxa, the three endoskeletal types may occur alone or in varying combinations. Often, endoskeletal elements appear only in the course of ontogeny, usually later than exoskeletal elements. In agglutinated shells endoskeletal elements include the septum and may be recognized by remarkably coarse and irregularly shaped particles that obscure the genetically fixed pattern in contrast to the more ordered exoskeletal elements of the same specimen. Whether the toothplates and their equivalents in lamellar perforate foraminifera and the secondary septa produced by folds of the inner lamella in orthophragminid lamellar architecture are homologous equivalents of the endoskeletal structures of non-lamellar-imperforate foraminifera remains an open question.

Difference between revisions of "Endoskeleton"

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 ==Definition==
 *''according to Hottinger (2006):''
-'''ENDOSKELETON''' - localized thickenings on the inner surface of the chamber wall that partly or totally subdivide the main chamber lumen in the lee of protoplasmic streams according to a pattern produced by the arrangement of intercameral foramina in successive septa. Plate-like elements ([[septula]]), usually perpendicular to the septum, may form more or less complete partitions touching the lateral walls or fusing with elements of the [[exoskeleton]]. Discontinuous, columnar partitions are called [[pillars]] (or interseptal pillars). A third type of endoskeleton is produced by layers of shell deposited on the chamber floor and coating the previously exposed outer shell surface completely ([[basal layer]]) or partially ([[chomata]] and [[parachomata]] of fusulinids). In different taxa, the three endoskeletal types may occur alone or in varying combinations. Fig. 47 & Fig. 63 . Often, endoskeletal elements appear only in the course of ontogeny, usually later than exoskeletal elements. In agglutinated shells endoskeletal elements include the septum and may be recognized by remarkably coarse and irregularly shaped particles that obscure the genetically fixed pattern in contrast to the more ordered exoskeletal elements of the same specimen. Whether the toothplates and their equivalents in lamellar perforate foraminifera and the secondary septa produced by folds of the inner lamella in orthophragminid lamellar architecture are homologous equivalents of the endoskeletal structures of non-lamellar-imperforate foraminifera remains an open question.
+'''ENDOSKELETON''' - localized thickenings on the inner surface of the chamber wall that partly or totally subdivide the main chamber lumen in the lee of protoplasmic streams according to a pattern produced by the arrangement of intercameral foramina in successive septa. Plate-like elements ([[septula]]), usually perpendicular to the septum, may form more or less complete partitions touching the lateral walls or fusing with elements of the [[exoskeleton]]. Discontinuous, columnar partitions are called [[pillars]] (or interseptal pillars). A third type of endoskeleton is produced by layers of shell deposited on the chamber floor and coating the previously exposed outer shell surface completely ([[basal layer]]) or partially ([[chomata]] and [[parachomata]] of fusulinids). In different taxa, the three endoskeletal types may occur alone or in varying combinations. Often, endoskeletal elements appear only in the course of ontogeny, usually later than exoskeletal elements. In agglutinated shells endoskeletal elements include the septum and may be recognized by remarkably coarse and irregularly shaped particles that obscure the genetically fixed pattern in contrast to the more ordered exoskeletal elements of the same specimen. Whether the toothplates and their equivalents in lamellar perforate foraminifera and the secondary septa produced by folds of the inner lamella in orthophragminid lamellar architecture are homologous equivalents of the endoskeletal structures of non-lamellar-imperforate foraminifera remains an open question.