A deep-sea agglutinated foraminifer tube constructed with planktonic foraminifer shells of a single species

Abstract

Abstract. Agglutinated foraminifera are marine protists that show apparently complex behaviour in constructing their shells, involving selecting suitable sedimentary grains from their environment, manipulating them in three dimensions, and cementing them precisely into position. Here we illustrate a striking and previously undescribed example of complex organisation in fragments of a tube-like foraminifer (questionably assigned to Rhabdammina) from 1466 m water depth on the northwest Australian margin. The tube is constructed from well-cemented siliciclastic grains which form a matrix into which hundreds of planktonic foraminifer shells are regularly spaced in apparently helical bands. These shells are of a single species, Turborotalita clarkei, which has been selected to the exclusion of all other bioclasts. The majority of shells are set horizontally in the matrix with the umbilical side upward. This mode of construction, as is the case with other agglutinated tests, seems to require either an extraordinarily selective trial-and-error process at the site of cementation or an active sensory and decision-making system within the cell.

Fractal analysis highlights analogies in arenaceous tubes of Sabellaria alveolata (Metazoa, Polychaeta) and agglutinated tests of foraminifera (Protista)

“…Grains are either selected or randomly picked from the water column or bottom sediment, then manipulated in three dimensions and cemented to form the agglutinated wall. This ability has been observed in unicellular organisms, such as tintinnids, testate amoebae and agglutinated foraminifera [e.g., [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], as well as in different multicellular groups, such as arthropods (tubicolous amphipods and tanaids, as well as caddisflies) and polychaete annelids [5,[21][22][23][24][25][26][27][28][29].…”