world of amoeboid organisms

Pontigulasia rhumbleri, with aperture and internal bridge

Genus  Pontigulasia Rhumbler, 1896

Diagnosis: Shell pyriform, sometimes with a constriction of the neck, either circular or compressed in transverse section; composed mainly of agglutinate mineral particles with some diatom frustules or siliceous plates, bound by a network of organic cement; aperture terminal, circular; internally the shell is divided into two regions by a narrow bridge, made mainly of organic cement with some agglutinate particles, stretched between the lateral walls at about one third of the body length from the aperture.

Known species:
P. rhumbleri Hopkinson, 1919 (type species)
P. compressoidea Jung, 1942
P. elisa (Penard, 1893)
P. sarrazinensis Chardez and Gaspar, 1984
P. spiralis Rhumbler, 1896.
P. pentangulostoma Quin et al., 2008

Remarks: Usually, the internal bridge is hard to detect due to the opaqueness of the shell. It is sometimes visible as a dark band at about one third of the shell length from the aperture. For the function of this bridge, see rotifers.

Pontigulasia, rather hyaline shell with bridge clearly visible, shell 126 µm, Naardermeer
Pontigulasia rhumbleri
Pontigulasia elisa
Ferry Siemensma, created February 28, 2019; last modified July 31, 2021
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