Nasser, N.A., Patterson, R.T. 2015. Conicocassis, a new genus of Arcellinida (Testate Lobose Amoebae). Palaeontologia Electronica. 18.3.46A: 1-11
Arcellinida (also informally known as thecamoebians or testate lobose amoebae) are a group of shelled benthic protists common in most Quaternary lacustrine sediments. They are found worldwide from the equator to poles and live in a variety of fresh to brackish aquatic and terrestrial habitats. More than 130 arcellacean species and strains are ascribed to the genus Centropyxis, within the family Centropyxidae, which includes species that are distinguished by having a flattened, beret-like test (shell). Conicocassis, a new arcellacean genus of Centropyxidae differs from other genera of the family by having a unique test comprised of two distinct components; an ovoid to spherical main test body, topped by a conical, funnel-like asymmetrically placed flange extending from around a small circular aperture. The genus is mainly found in very wet mosses and aquatic environments in High Arctic regions of Europe and North America, and has also been identified in samples from peatlands in Germany, the Netherlands and Austria. This paper extends the known geographic distribution of the genus in North America southward to include lacustrine environments in the Central Northwest Territories of Canada.