Pontigulasia montana Ogden and Zivkovic, 1983

Diagnosis: Shell pyriform, bluntly rounded aborally for one-third of its length and usually tapering gradually from the widest point towards the aperture, although sometimes there is a distinct constriction at the position of the internal aperture. It is composed of a mixture of mainly medium to large pieces of quartz arranged to give a rough surface. Organic cement is often seen as part of the shell matrix. The external aperture is roughly circular and surrounded by small or medium particles randomly positioned to give it an irregular margin. The smaller, single, internal aperture is also circular and surrounded by small particles overlaid with organic cement.

Dimensions: Ogden and Zivkovic (1983) 91-125 µm.

Ecology: Freshwater, detritus.

Remarks: (Ogden and Zivkovic,1983) “The specimens described here are similar to Pontigulasia bryophila Penard, 1902, but the latter species has a more streamlined, elongate shell, with smaller internal and external openings, plus a distinct organic cement pattern. Comparison of the measurements (…) emphasizes the difference in body and apertural size between these two species, furthermore, P. bryophila appears to be the only previously described species of Pontigulasia with a single internal aperture.”