Calcarina defrancii, from here.

Belongs within: Rotalioidea.

The Calcarinidae are a group of Foraminifera known from the Upper Cretaceous to the present, often with large spinose outgrowths on the test (Loeblich & Tappan 1964b).

Star sands
Published 19 April 2010
Star-shaped forams, Calcarina sp., on an algal substrate. Photo from here.
Star-shaped forams, Calcarina sp., on an algal substrate. Photo from here.

About a month ago, I presented my first post on the marine shell-bearing protists known as foraminiferans. That post was on forams that constructed their shell by gluing together sand but I mentioned that there were other families that secreted their shells themselves. Some of these families can reach sizes large enough to be seen with the naked eye (over a millimetre and sometimes well over a centimetre in diameter); the Indo-Pacific calcareous Calcarinidae are one of these larger families. Such large forams live in association with endosymbiotic algae and have been given the evocative name of ‘living sands’ (Lee 1995).

Among the living sands, the shape of Calcarinidae is distinctive. Their basic form is trochoid (i.e. shaped like a top shell, a Trochus) and similar to species of the related family Rotaliidae (Cushman 1940) but extra shell material and chambers are laid down over and around the central trochoid structure. Large blunt external spines radiate from the sides of the foram, often giving the whole a star-like appearance when viewed from above. A system of canals runs between the chambers and along the spines allowing for the passage of cytoplasm between the chambers and the outside world. The chosen symbionts of calcarinids are diatoms which are held in special vacuoles inside the chambers. Symbiotic forams do still feed on other micro-organisms as well as deriving nutrients from their endosymbionts (Lee 1995) but laboratory studies have shown that calcarinids are capable of living solely on nutrients derived from their diatoms in the absence of another food supply (Röttger & Krüger 1990). If the algal symbionts are killed, the forams cannot live long without them though they may replace them if the opportunity arises in time (Lee 1995).

Living specimen of Baculogypsina sphaerulata with cytoplasm emerging from the spines. Figure from Röttger & Krüger (1990); size is 2 mm across.

Calcarinids can make up a significant part of coastal calcareous deposits in the Indo-Pacific region; one of the most fun expressions of this abundance was made by Lee (1995) who commented that calcarinid deposits in one part of Japan were “so abundant that they can be scraped together by hand to build sand castles”. Because of their dependence on their diatom symbionts, calcarinids are only found in shallow waters, mostly preferring high energy environments (Lobegeier 2002). Many calcarinids live as epiphytes on macroalgae and seagrasses where they attach themselves to their substrate by means of cytoplasm extended through the spine canals (Röttger & Krüger 1990); among filamentous algae the spines themselves may form a mechanical anchor among tangled filaments (Lobegeier 2002).

Systematics of Calcarinidae

Characters (from Loeblich & Tappan 1964b): Test coiled, without differentiation into spiral and umbilical surfaces, advanced genera may become globula, large spines formed by thickenings, not marginal projections of chambers; canal system diffused, confused with perforations.

Calcarinidae [Calcarinoidea]
    |  i. s.: Schlumbergerella Hanzawa 1952LT64b
    |           `--*S. floresiana (Schlumberger 1896) [=Baculogypsina floresiana]LT64b
    |         Silvestriella Hanzawa 1952LT64b
    |           `--S. tetraedra (Gümbel 1870)B-F08, LT64b (see below for synonymy)
    |         Meghalayana Matsumaru & Sarma 2008B-F08
    |           `--M. indicaB-F08
    |--Calcarina d’Orbigny 1826C40
    |    |--*C. spengleri (Gmelin 1788) [=Nautilus spengleri]LT64b
    |    |--C. clavigeraH04
    |    |--C. defranciiLT64a
    |    |--C. mackayiQ72
    |    `--C. verriculataQ72
    `--+--Siderolites Lamarck 1801C40 (see below for synonymy)
       |    `--*S. calcitrapoides Lamarck 1801C40 (see below for synonymy)
       |--Baculogypsinoides Yabe & Hanzawa 1930C40
       |    `--*B. spinosus Yabe & Hanzawa 1930C40
       `--Baculogypsina Sacco 1893C40 [incl. Taurogypsina Sacco 1893LT64b, Tinoporus de Montfort 1808 (n. d.)LT64b]
            |--*B. sphaerulata (Parker & Jones 1860)LT64b (see below for synonymy)
            |--‘Tinoporus’ lucidusN79
            `--*Taurogypsina’ taurobaculata Sacco 1893LT64b

*Baculogypsina sphaerulata (Parker & Jones 1860)LT64b [=Orbitolina sphaerulataC40; incl. *Tinoporus baculatus de Montfort 1808 (n. d.)LT64b, LT64a, LT64b]

Siderolites Lamarck 1801C40 [=Siderolina Defrance 1824LT64b, Siderolithes de Montfort 1808LT64b, Siderolithus Bronn 1838LT64b; incl. Sideroporus Bronn 1825LT64b]

*Siderolites calcitrapoides Lamarck 1801C40 [=*Siderolina calcitrapoidesLT64b, *Siderolithes calcitrapoidesLT64b, *Siderolithus calcitrapoidesLT64b; incl. *Sideroporus calcitrapa Bronn 1825LT64b, Osteratites (l. c. for Asteriatites) siderolitesWR78]

Silvestriella tetraedra (Gümbel 1870)B-F08, LT64b [=Calcarina tetraedraLT64b, Baculogypsinoides tetraedraLT64b, Siderolites tetraedraLT64b]

*Type species of generic name indicated


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

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

[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.

Lee, J. T. 1995. Living sands. BioScience 45 (4): 252–261.

Lobegeier, M. K. 2002. Benthic foraminifera of the family Calcarinidae from Green Island Reef, Great Barrier Reef province. Journal of Foraminiferal Research 32 (3): 201–216.

[LT64a] Loeblich, A. R., Jr & H. Tappan. 1964a. Sarcodina: chiefly “thecamoebians” and Foraminiferida. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt C. Protista 2 vol. 1. The Geological Society of America and The University of Kansas Press.

[LT64b] Loeblich, A. R., Jr & H. Tappan. 1964b. 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.

[N79] Norman, A. M. 1879. The Mollusca of the fiords near Bergen, Norway. Journal of Conchology 2: 8–77.

[Q72] Quilty, P. G. 1972. The biostratigraphy of the Tasmanian marine Tertiary. Papers and Proceedings of the Royal Society of Tasmania 106: 25–44.

Röttger, R., & R. Krüger. 1990. Observations on the biology of Calcarinidae (Foraminiferida). Marine Biology 106 (3): 419–425.

[WR78] Wienberg Rasmussen, H. 1978. Articulata. In: Moore, R. C., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt T. Echinodermata 2. Crinoidea vol. 3 pp. T813–T927. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).


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