Difference between revisions of "Central complex"

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[[File:Fig 47.jpg|thumb|<font size="2">'''Fig. 3.'''  Endoskeletal patterns in discoidal shells.
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[[File:Fig 47.jpg|thumb|<font size="2">'''Fig. 3.'''  Endoskeletal patterns in discoidal shells (after HOTTINGER, 1967) '''H1-2:''' ''Orbitolites spp.'' from the region of Tremp, Lerida prov., Northern Spain. Pyrenean Lower Eocene (Ilerdian). '''H1:''' the comparatively regular disposition of the ramps in sections parallel to the equatorial plane reveals their superposition in consecutive stolon planes. '''H2:''' in the transverse section parallel to the axis of the shell this superposition is clearly visible where the section is tangential to an annular septum.
'''A-D:''' disposition of apertural axes. '''A:''' radial axes alternating in radial position from one stolon layer to the next. This is the most common disposition in imperforate forms with annular stages of growth. '''B:''' radial axes superposed in radial position on all stolon planes. '''C:''' crosswise-oblique stolon axes alternating in radial position from one stolon plane to the next. '''D:''' crosswise-oblique stolon axes superposed on all stolon planes. This pattern characterizes all members of the orbitolitid family. Schematic, not to scale. '''E-H:''' all endoskeletal elements are disposed in accordance with the basic patterns of the foraminal axes: E corresponds to pattern A, F to pattern B, G to pattern C and H to pattern D. Stereographs after Hottinger, 1967. Schematic, not to scale. In reality, the patterns are often disturbed by intercalary elements generated as the diameter of the annuli increases during growth. This maintains on the apertural face the mean distances between apertures and their mean diameter constant during ontogeny. Examples: E1-2: ''Pseudotaberina malabarica'', megalospheric generation, from Iran. Middle Miocene. '''E1:''' oblique-centered section of spiral-involute stage showing radial disposition of pillars. Laterally, there is a layer of short septula. '''E2:''' a transverse section tangential to a septum shows the alternating disposition of the foramina and the pillars. '''F1-2:''' New genus (possibly related to ''Pastrikella'') from the Pyrenean Upper Cretaceous in Northern Spain. The endoskeleton consists only of septula. There is but one median annular preseptal passage and it occupies the total radial extension of the annular chamber. There are only two planes of stolons. '''F1:''' an oblique section at a low angles with respect to the equatorial plane shows the radial disposition of the apertural axes and of the septula. '''F2:''' a transverse section parallel to the shell axis shows that the stolon axes on the two stolon planes are superposed. '''G1-3:''' ''Amphisorus'' from Rottnest Island near Perth, Australia. Recent. '''G1:''' the detail of an equatorial section demonstrates the crosswise-oblique disposition of the pillars on neighboring stolon planes. G2, an equatorial section, demonstrates that pillars are restricted to the equatorial zone of the disc. '''G3:''' a transverse section parallel to the shell axis and tangential to an annular septum shows the disposition of the median foramina and pillars altermating in radial position on successive stolon planes. They are flanked by two annular preseptal passages separating them from a lateral layer of septula subdividing the annular chamber. '''H1-2:''' ''Orbitolites spp.'' from the region of Tremp, Lerida prov., Northern Spain. Pyrenean Lower Eocene (Ilerdian). '''H1:''' the comparatively regular disposition of the ramps in sections parallel to the equatorial plane reveals their superposition in consecutive stolon planes. '''H2:''' in the transverse section parallel to the axis of the shell this superposition is clearly visible where the section is tangential to an annular septum.
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Abbreviations:'''f:''' foramen; '''ra:''' ramp; '''s:''' septum; '''sl:''' septulum; (Hottinger, 2006; fig. 47 [http://paleopolis.rediris.es/cg/CG2006_M02/index.html] '''CC'''/BY-NC-SA)]]
Abbreviations: '''b:''' beam; '''f:''' foramen; '''pi:''' pillar; '''prp:''' preseptal space; '''ra:''' ramp; '''s:''' septum; '''sl:''' septulum; (Hottinger, 2006; fig. 47)[http://paleopolis.rediris.es/cg/CG2006_M02/index.html] '''CC'''/BY-NC-SA)]]
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[[File:Fig 80.jpg|thumb|<font size="2">'''Fig. 4.''' Stolon planes and foramenal axes in discoidal-annular and conical-uniserial shells. Schematic, not to scale. Arrangement of stolon axes on cone mantles in the so-called radial zone of the cone is in accordance with the four basic patterns that govern discoidal structures. In conical shells, however, the stolon planes are replaced by cone mantles. As the cone increases in radius during growth, new stolon axes are intercalated in the cone mantles (arrows). G: crosswise-oblique arrangement of stolon axes in line on a shell radius on subsequent cone mantles. This structure is a characteristic of Orbitolina; (Hottinger, 2006; fig. 80 [http://paleopolis.rediris.es/cg/CG2006_M02/index.html] '''CC'''/BY-NC-SA)]]
  
[[File:Fig 80.jpg|thumb|<font size="2">'''Fig. 4.'''  Stolon planes and foramenal axes in discoidal-annular and conical-uniserial shells. Schematic, not to scale. '''B:''' A cone composed of a single series of discoidal chambers of which the marginal and axial areas are differentiated by colour. Note the distribution of the marginal area, the emplacement of the exoskeleton, and of the axial area housing the endoskeleton, in axial, horizontal (basal) and transverse sections. The axis of the shell is indicated by a vertical arrow. The surface of the cone is called the cone mantle, its horizontal termination is the cone base. A vertical line on the slanting surface of the cone is called a cone mantle line. The cone radius is indicated by a double arrow. (Hottinger, 2006; fig. 80 [http://paleopolis.rediris.es/cg/CG2006_M02/index.html] '''CC'''/BY-NC-SA)]]
 
 
__FORCETOC__
 
__FORCETOC__
 
==Definition==
 
==Definition==
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* [[reticular zone]]
 
* [[reticular zone]]
 
==References==
 
==References==
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Henson (1948), Larger imperforate Foraminifera of south-western Asia, Families Lituolidae, Orbitolinidae and Meandrosipinidae, British Museum (Natural History), London, 127 p. + 16 pls.
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Hottinger (1967), Foraminifères imperforés du Mésozoïque marocain, Notes et Mémoires du Service géologique, Rabat, N° 209, p. 5-168
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Hottinger (2006), [http://paleopolis.rediris.es/cg/CG2006_M02/index.html Illustrated glossary of terms used in foraminiferal research]. [http://paleopolis.rediris.es/cg/uk-index.html Carnets de Géologie], [http://paleopolis.rediris.es/cg/CG2006_M02/index.html Memoir 2], ISSN 1634-0744             
 
Hottinger (2006), [http://paleopolis.rediris.es/cg/CG2006_M02/index.html Illustrated glossary of terms used in foraminiferal research]. [http://paleopolis.rediris.es/cg/uk-index.html Carnets de Géologie], [http://paleopolis.rediris.es/cg/CG2006_M02/index.html Memoir 2], ISSN 1634-0744             
  
  
 
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Revision as of 10:32, 15 April 2019

Fig. 1. Henson's "zonation" of discoidal chambers in uniserial-conical shells, namely the marginal, radial and reticulate zones. Compare Fig. 2 From Henson, 1948; (Hottinger, 2006; fig. 20)[1] CC/BY-NC-SA)
Fig. 2.The structure of Orbitolina.A-D: Oblique and vertical views of the cone base. These plasticine models sculptured in the years around 1955 by M. Richel (* 1896 - † 1984) were never published. E-F: Details of a septulum in the radial zone of the discoidal chamber. In model E the septulum is cut below the roof and above the bottom of the chambers. The apparent folding of the section results from the adjustment of the endoskeletal structure to the crosswise-oblique arrangement of the stolon axes (arrows) that produce so-called ramps. In model F the septulum is cut in the middle of the chamber and shows a part of the chamber bottom with the face of the previous chamber. In the middle of the chamber, the section of the septulum appears unfolded. Compare Fig. 3 and Fig. 4 G-H: Random thinsections of Orbitolina sp. from Southwestern France, Albian. Transmitted light micrographs. In Fig. G the approximate positions of sections H-K are indicated. Note the inverse orientation: the sections face downward. G-K: Random sections of Orbitolina sp. from Southwestern France, Albian. Transmitted light micrographs. The approximate position of sections H-K are indicated in section G that is very close to the axial plane. For Henson's zonation of the chamber see Fig. 1. Section H demonstrates details of the reticular zone, section I details of the marginal zone and section J details of the radial zone. The transverse section K shows the ramps produced by the crosswise-oblique stolon system. a: aperture; af: apertural face; b: beam; cl: chamberlet; e: epiderm; f: foramen; gr: coarse grains in the septum that obscure the structural pattern; hor: horizontal section in the plasticine model; marg: marginal zone; r: rafter; ra: ramp; rad: radial zone; ret: reticular zone; s: septum; sf: septal face; sl: septulum; sut: suture of the chambers. Double arrows in E and F: crosswise oblique foraminal axes; (Hottinger, 2006; fig. 71)[2] CC/BY-NC-SA)


Fig. 3. Endoskeletal patterns in discoidal shells (after HOTTINGER, 1967) H1-2: Orbitolites spp. from the region of Tremp, Lerida prov., Northern Spain. Pyrenean Lower Eocene (Ilerdian). H1: the comparatively regular disposition of the ramps in sections parallel to the equatorial plane reveals their superposition in consecutive stolon planes. H2: in the transverse section parallel to the axis of the shell this superposition is clearly visible where the section is tangential to an annular septum. Abbreviations:f: foramen; ra: ramp; s: septum; sl: septulum; (Hottinger, 2006; fig. 47 [3] CC/BY-NC-SA)
Fig. 4. Stolon planes and foramenal axes in discoidal-annular and conical-uniserial shells. Schematic, not to scale. Arrangement of stolon axes on cone mantles in the so-called radial zone of the cone is in accordance with the four basic patterns that govern discoidal structures. In conical shells, however, the stolon planes are replaced by cone mantles. As the cone increases in radius during growth, new stolon axes are intercalated in the cone mantles (arrows). G: crosswise-oblique arrangement of stolon axes in line on a shell radius on subsequent cone mantles. This structure is a characteristic of Orbitolina; (Hottinger, 2006; fig. 80 [4] CC/BY-NC-SA)


Definition

  • according to Hottinger (2006):

CENTRAL COMPLEX - see reticular zone. Adaxial cone in conical agglutinated forms where radial septula are fused to an irregular pattern of meshes. In contrast to radial zone and marginal zone.






See also

References

Henson (1948), Larger imperforate Foraminifera of south-western Asia, Families Lituolidae, Orbitolinidae and Meandrosipinidae, British Museum (Natural History), London, 127 p. + 16 pls.

Hottinger (1967), Foraminifères imperforés du Mésozoïque marocain, Notes et Mémoires du Service géologique, Rabat, N° 209, p. 5-168

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


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