Turrilina alsatica, from Grimm (2002).

Belongs within: Rotaliida.

Forams with teeth
Published 27 August 2016

Time for another foram post. The above image (copyright Robert P. Speijer, scale bar = 100 µm) shows Turrilina brevispira, a typical Eocene representative of the foram subfamily Turrilininae.

The Turrilininae are a group of calcareous forams that first appeared in Middle Jurassic (Loeblich & Tappan 1964). In most species, the test is what is called a ‘high trochospiral’ form: that is, it coils in a similar manner to, and overall looks rather like, a high-shelled snail. Each of these whorls is divided into at least three successive chambers, sometimes more. At the end of the test is a loop-shaped aperture. At least one species of turrilinine, Floresina amphiphaga, is a predator/parasite of other forams, drilling into their test to extract their protoplasm.

The turrilinines are most commonly classified in a broader foram superfamily known as the Buliminoidea or Bulimnacea. Other buliminoids commonly resemble turrilinines in their overall form. The group has commonly been defined, however, on the basis of what is called a ‘tooth-plate’. This is an outgrowth of the internal wall of the test that runs between the apertures of each chamber. The exact appearance of the tooth-plate differs between taxa; in Turrilina, for instance, it is a trough-shaped pillar that is usually serrated along one end (Revets 1987). I have no idea what the function of the tooth-plate is, if indeed any is known, whether it provides an anchor for some cytoplasmic structure or anything else. However, in more recent decades a number of authors have questioned whether the tooth-plate is as significant a taxonomic feature as previously thought. For instance, Tosaia is a Recent genus of foram whose overall morphology and chamber arrangement is fairly typical for the Turrilininae but which lacks any sign of a tooth-plate (Nomura 1985). Excluding Tosaia from the buliminoids on this basis alone would imply a remarkably strong evolutionary convergence of every other feature of this genus.

Systematics of Turrilinidae
    |--Turrilina Andreae 1884C40 [incl. Corrosina Nyirö 1954LT64; TurrilininaeM13]
    |    |--*T. alsatica Andreae 1884C40
    |    |--T. andreaciC40
    |    `--T. pupoides (Nyirö 1954) [=*Corrosina pupoides]LT64
         |--Sporobulimina Stone 1949LT64
         |    `--*S. perforata Stone 1949LT64
         `--Sporobuliminella Stone 1949M13, LT64
              `--*S. stainforthi Stone 1949LT64
Turrilinidae incertae sedis:
  Buliminellita Cushman & Stainforth 1947LT64
    `--*B. mirifica Cushman & Stainforth 1947LT64
  Neobulimina Cushman & Wickenden 1928LT64
    |--*N. canadensis Cushman & Wickenden 1928C40
    `--N. spicataBL79
  Praebulimina Hofker 1953LT64
    |--P. reussi (Morrow 1934) (see below for synonymy)LT64
    |--P. carseyaeM08
    |--P. kickapooensisM08
    |--P. nanninaBL79
    |--P. raraBL79
    `--P. ventricosa [=Bulimina ventricosa]LT64
  Pyramidina Brotzen 1948LT64
    |--*P. curvisuturata (Brotzen 1940) [=Bulimina curvisuturata]LT64
    `--P. cushmani [=Reussella cushmani]LT64

Praebulimina reussi (Morrow 1934) [=Bulimina reussi, B. ovulum Reuss 1844 non B. ovula d’Orbigny 1839, *Praebulimina ovulum]LT64

*Type species of generic name indicated


[BL79] Basov, V. A., B. G. Lopatin, I. S. Gramberg, A. I. Danjushevskaya, V. Ya. Kaban’kov, V. M. Lazurkin & D. K. Patrunov. 1979. Lower Cretaceous lithostratigraphy near Galicia Bank. Initial Reports of the Deep Sea Drilling Project 47: 683–717.

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

[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.

[M08] McMillan, I. K. 2008. Reappraisal of foraminiferal assemblages of the Santonian–Campanian Mzamba Formation type section, and their correlation with the stratigraphic succession of the KwaZulu Basin. African Natural History 4: 25–34.

Nomura, R. 1985. On the genus Tosaia (Foraminiferida) and its suprageneric classification. Journal of Paleontology 59 (1): 222–225.

Revets, S. A. 1987. A revision of the genus Turrilina Andreae, 1884. Journal of Foraminiferal Research 17 (4): 321–332.

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