Difference between revisions of "Glossary"
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Introduction | Introduction | ||
| − | + | The terminology used by various authors in describing the morphological features of the foraminiferal test is far from being unified and varies greatly from case to case (compare e.g. Reiss, 1963, Hottinger, 1978, Hottinger et al., 1990, 1993, Loeblich and Tappan, 1964, 1987). The reasons for the variety of terms for the same feature are in most cases not at all formal, but due to differences of opinion with regard to the significance of features, concerning homologies and analogies, to differences in levels of accuracy, as well as due to different methods of observation (Hottinger, 1978). | |
The terms listed in the following Glossary, are accompanied [in square brackets] by alternative terms used and (in round brackets) by terms considered to be synonymous, partially synonymous, unclear or for other reasons to be avoided. | The terms listed in the following Glossary, are accompanied [in square brackets] by alternative terms used and (in round brackets) by terms considered to be synonymous, partially synonymous, unclear or for other reasons to be avoided. | ||
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Remarks: The term alveole is used here exclusively for exoskeletal structures, i.e. for subepidermal, tiny compartments of the chamber cavity coated by organic lining. Alveoles must be distinguished from paraporous or keriothecal cavities belonging to the wall texture. The latter are (by definititon) not filled with living chamber plasm nor coated by the organic lining. The simultaneous presence of both alveolar structures and keriothecal wall texture in the fusulinid Verbeekina and its relatives, the combination of an alveolar exoskeleton with a paraporous external wall in Dicyclina or with a bilamellar perforate wall in Fabiania supports a consequent restriction of the term's use to exoskeletal structures, never to textures. | Remarks: The term alveole is used here exclusively for exoskeletal structures, i.e. for subepidermal, tiny compartments of the chamber cavity coated by organic lining. Alveoles must be distinguished from paraporous or keriothecal cavities belonging to the wall texture. The latter are (by definititon) not filled with living chamber plasm nor coated by the organic lining. The simultaneous presence of both alveolar structures and keriothecal wall texture in the fusulinid Verbeekina and its relatives, the combination of an alveolar exoskeleton with a paraporous external wall in Dicyclina or with a bilamellar perforate wall in Fabiania supports a consequent restriction of the term's use to exoskeletal structures, never to textures. | ||
Layers of alveoles coating the lateral chamber wall are present in various agglutinated groups of which Cyclammina is the most prominent while Everticyclammina is an early extinct representative of an exoskeletal layer of exclusively undivided, shallow alveoles. The Neogene group of Textulariella (GrÚnhagen and Luterbacher, 1966) has branching alveoles. Among the porcelaneous foraminifera, Austrotrillina may be an unique group. In this genus, species with deep and branching alveoles (A. howchini, Adams, 1968) are said to evolve from earlier forms with layers of shallow, undivided alveoles. | Layers of alveoles coating the lateral chamber wall are present in various agglutinated groups of which Cyclammina is the most prominent while Everticyclammina is an early extinct representative of an exoskeletal layer of exclusively undivided, shallow alveoles. The Neogene group of Textulariella (GrÚnhagen and Luterbacher, 1966) has branching alveoles. Among the porcelaneous foraminifera, Austrotrillina may be an unique group. In this genus, species with deep and branching alveoles (A. howchini, Adams, 1968) are said to evolve from earlier forms with layers of shallow, undivided alveoles. | ||
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* The term alveole is also used for rows of blind recesses in postseptal position over supplementary apertures in the previous septal face as in Subalveolina or Bullalveolina. We do not yet know, how to interpret (in terms of exo- or endoskeletal elements) these alveoles nor what might be their biological meaning. Annular arrangement - arrangement of concentric annular chambers. 81/6. 226/3. | * The term alveole is also used for rows of blind recesses in postseptal position over supplementary apertures in the previous septal face as in Subalveolina or Bullalveolina. We do not yet know, how to interpret (in terms of exo- or endoskeletal elements) these alveoles nor what might be their biological meaning. Annular arrangement - arrangement of concentric annular chambers. 81/6. 226/3. | ||
* Annular canal - free space between endo- and exoskeletal structures in spirocyclinids. | * Annular canal - free space between endo- and exoskeletal structures in spirocyclinids. | ||
