Miogypsinidae

Miogypsina intermedia, from Van Gorsel et al. (2014).

Belongs within: Rotalioidea.

Spiral, then spread
Published 18 January 2011
Vertical (1-3, 7) and transverse (4-6) sections of Miogypsinoides dehaarti, from Cole (1939).

Miogypsinoides dehaarti was a large calcareous foraminiferan (up to a few millimetres in length) that lived during the Aquitanian period (lower Miocene). The test of M. dehaarti and other species of Miogypsinoides was divided vertically into three distinct layers: the chambers were laid in a plane along the midline of the test with a thick unchambered wall above and below. The ventral wall contained a lattice system of canals that in life may have contained cytoplasm running between the chambers and the outside world (de Bock 1976); the upper wall was unperforated. The first part of the test to grow is visible in the lower point of the transverse sections above: from the embryonic chambers, the juvenile test initially grew in a spiral (with the size and proportions of the spiral varying between species). After the juvenile test reached maturity*, new chambers were added in a fan from one side of the juvenile test, so the eventual form of Miogypsinoides was not dissimilar to a piece of candy corn (though we do not know whether it, too, tasted of sweetness and death). The juvenile test of Miogypsinoides is similar to the adult form of other rotaliid forams, and it probably evolved from such forms through a process of hypermorphosis (the addition of new adult stages to development).

*Developmental maturity, that is. Obviously, we have no idea when the foram reached reproductive maturity.

Sectional diagram of the apical end of Miogypsinoides, showing the chambers in the equatorial plane and with some sections of the canal system visible below. Figure from Bock (1976).

The genus Miogypsinoides may have been ancestral to other genera in the family Miogypsinidae (Hanzawa 1964), from which it differs by the presence in the latter of accessory lateral chambers in the dorsal and ventral walls (and hence the loss of the canal system in the ventral wall). In the genera Miolepidocyclina and Heterosteginoides, the juvenile test moved from the apical position of Miogypsinoides to a a central position, and the adult test became conical (Hanzawa 1962). Some authors treat some or all of these genera as subgenera of Miogypsina (which, in the sense of Hanzawa 1962, had lateral chambers like Miolepidocyclina but an apical juvenile test like Miogypsinoides). Hanzawa (1964) treated them as separate but nevertheless derived both Miogypsina and Heterosteginoides from Miogypsinoides polyphyletically, evidently basing his classification on the overall shape of the adult test but his phylogeny on stratigraphy and the juvenile test. The Miogypsinidae as a whole became extinct in the middle Miocene.

Systematics of Miogypsinidae
Miogypsinidae
|--Boninella Matsumary 1996B-F08
|--Miogypsinodella BouDagher-Fadel et al. 2000B-F08
|--Paleomiogypsina Matsumaru 1996B-F08
| `--P. boninensisB-F08
|--Miogypsinita Drooger 1952B-F08
| `--*M. mexicana (Nuttall 1933)LT64 [=Miogypsina mexicanaLT64, Miolepidocyclina mexicanaB-F08]
|--Miogypsinella Hanzawa 1940LT64
| |--*M. borodinensis Hanzawa 1940LT64, B-F08, LT64
| `--M. ubaghsiB-F08
|--Miolepidocyclina Silvestri 1907 [incl. Heterosteginoides Cushman 1918]LT64
| |--*M. burdigalensis (Gümbel 1870) (see below for synonymy)LT64
| `--M. panamensis (Cushman 1918)B-F08, LT64 [=*Heterosteginoides panamensisLT64]
|--Miogypsinoides Yabe & Hanzawa 1928 [incl. Conomiogypsinoides Tan 1936]LT64
| |--*M. dehaarti [=Miogypsina dehaarti]C40
| |--M. abunensis (Tobler 1927)B-F08, LT64 [=Miogypsina abuensisLT64, *Conomiogypsinoides abuensisLT64]
| |--M. bantamensisB-F08
| |--M. complanatusB-F08
| |--M. formosensisB-F08 [=M. dehaarti var. formosensisC40]
| `--M. indicusB-F08
`--Miogypsina Sacco 1893 (see below for synonymy)LT64
|--*M. globulina (Michelotti 1841) [=Nummulites globulina; incl. *Flabelliporus dilatatus Dervieux 1894]LT64
|--M. antilleaB-F08
|--M. bantamensisP79
|--M. bifidaB-F08
|--M. borneensisB-F08
|--M. complanataP79
|--M. cushmaniC40
|--M. formosensisP79
|--M. gunteri Cole 1938 [=*Miogypsinopsis gunteri]LT64
|--M. indonesiensisB-F08
|--M. intermediaP79
|--M. mediterraneaP79
|--M. septentrionalisP79
|--M. taniP79
`--*Lepidosemicylcina’ thecideaeformis Rutten 1911LT64

Miogypsina Sacco 1893 [incl. Flabelliporus Dervieux 1894, Lepidosemicyclina Rutten 1911, Miogypsinopsis Hazawa 1940]LT64

*Miolepidocyclina burdigalensis (Gümbel 1870) [=Orbitoides (Lepidocyclina) burdigalensis, Miogypsina (*Miolepidocyclina) burdigalensis]LT64

*Type species of generic name indicated

References

Bock, J. F. de. 1976. Studies on some MiogypsinoidesMiogypsina s.s. associations with special reference to morphological features. Scripta Geologica 36: 1–135.

[B-F08] BouDagher-Fadel, M. K. 2008. The Cenozoic larger benthic foraminifera: the Palaeogene. Developments in Palaeontology and Stratigraphy 21: 297–418.

Cole, W. S. 1939. Large Foraminifera from Guam. Journal of Paleontology 13 (2): 183–189.

[C40] Cushman, J. A. 1940. Foraminifera: Their classification and economic use 3rd ed. Harvard University Press: Cambridge (Massachusetts).

Hanzawa, S. 1962. Upper Cretaceous and Tertiary three-layered larger Foraminifera and their allied forms. Micropaleontology 8 (2): 129–186.

Hanzawa, S. 1964. The phylomorphogeneses of the Tertiary foraminiferal families, Lepidocyclinidae and Miogypsinidae. Science Reports of the Tohoku University, second series, Geology 35 (3): 295–313.

[LT64] Loeblich, A. R., Jr & H. Tappan. 1964. Sarcodina: chiefly “thecamoebians” and Foraminiferida. In Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt C. Protista 2 vol. 2. The Geological Society of America and The University of Kansas Press.

[P79] Papp, A. 1979. Tertiary. In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A488–A504. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

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