Difference between revisions of "Trimorphism"

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[[File:Fig 05.gif|thumb|<font size="2"> '''Fig. 1.''' Standard dimorphic or trimorphic reproductive cycle in benthic, medium- to large-sized foraminifera according to Goldstein, 1999. Schizogeny, eventually repeated several times, may be widespread in larger foraminifera from oligotrophic habitats. Planktic foraminifera seem to have no dimorphic life cycle. Life cycles are linked in various ways to seasonal cycles. Example: Heterostegina depressa d'Orbigny, equatorial sections, Gulf of Aqaba, Red Sea (from Hottinger, 1977); (Hottinger, 2006; fig. 5 [http://paleopolis.rediris.es/cg/CG2006_M02/index.html] '''CC'''/BY-NC-SA)]]
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[[File:Fig 05.gif|thumb|<font size="2"> '''Fig. 1.''' Standard dimorphic or trimorphic reproductive cycle in benthic, medium- to large-sized foraminifera according to Goldstein, 1999. Schizogeny, eventually repeated several times, may be widespread in larger foraminifera from oligotrophic habitats. Planktic foraminifera seem to have no dimorphic life cycle. Life cycles are linked in various ways to seasonal cycles. Example: ''Heterostegina depressa'' d'Orbigny, equatorial sections, Gulf of Aqaba, Red Sea (from Hottinger, 1977); (Hottinger, 2006; fig. 5 [http://paleopolis.rediris.es/cg/CG2006_M02/index.html] '''CC'''/BY-NC-SA)]]
 
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==Definition==
 
==Definition==

Latest revision as of 15:02, 17 April 2019

Fig. 1. Standard dimorphic or trimorphic reproductive cycle in benthic, medium- to large-sized foraminifera according to Goldstein, 1999. Schizogeny, eventually repeated several times, may be widespread in larger foraminifera from oligotrophic habitats. Planktic foraminifera seem to have no dimorphic life cycle. Life cycles are linked in various ways to seasonal cycles. Example: Heterostegina depressa d'Orbigny, equatorial sections, Gulf of Aqaba, Red Sea (from Hottinger, 1977); (Hottinger, 2006; fig. 5 [1] CC/BY-NC-SA)

Definition

  • according to Hottinger (2006):

TRIMORPHISM - a morphologic differentiation of the megalospheric generation in A1 and A2. A1 has a comparatively small megalosphere and reaches larger adult shell sizes than A2. The A1 shells are interpreted (Hofker, 1968) as representing diploid schizonts generated by the microspheric agamont. The A2 shells, after the reduction division of the reproductive nuclei in A1, would represent haploid gamonts reproducing sexually. Thus, three different phenotypes would represent a (trimorphic) species.



See also

References

Goldstein (1999), Foraminifera, a biological overview. In: Sen Gupta B.K. (ed.), Modern Foraminifera, Kluwer Academic Publishers, Dortrecht, p. 37-55.

Hofker (1968), Studies of Foraminifer. Part I. General problems, Publicaties van het Natuurhistorisch Genootschap in Limburg, Maastricht, Reeks XVII, Aflevring 1-2, 135 p.

Hottinger (1977), Foraminifères operculiniformes. Mémoires du Muséum National d'Histoire Naturelle, Paris, (Série C, Sciences de la terre), t. XL, 159 p. + 66 pls.

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

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