Agglutinated tests in post-Sturtian cap carbonates of Namibia and Mongolia

Preservational and Morphological Variability of Assemblages of Agglutinated Eukaryotes in Cryogenian Cap Carbonates of Northern Namibia

“…The morphologies and compositions of the oval and round tests are consistent with those of modern agglutinated testate amoebae, probably related to the arcellinid amoebozoans (Bosak et al, 2011a). Microbial laminites at Okaaru also preserve rare tubular agglutinated forms and large oval forms with one blunt end, resembling modern monothalamous tubular and globular foraminiferans (Bosak et al, 2011a(Bosak et al, , 2012. These initial findings from the Rasthof Formation at Ongongo and Okaaru, as well as a recent report of large phosphatized forms named Otavia from pre-Sturtian Namibian carbonates and the interglacial carbonates of the Ombaatjie Formation (Brain et al, 2012), inspire questions about the stratigraphic occurrence and variations of fossils within the Rasthof Formation.…”

“…Lengths and widths of 114 microfossils from South Ombepera were measured using Olympus BH-2 microscope and DP Controller imaging software. Two-sample t-tests were employed to compare these dimensions to the dimensions of previously reported microfossil assemblages (Bosak et al, 2011a).…”

“…Colored dots at Ombepera and South Ombepera mark the stratigraphic positions of fossiliferous and unfossiliferous samples, respectively. Fossiliferous samples from Ongongo and Okaaru described in Bosak et al (2011aBosak et al ( , 2012 are shown at the appropriate stratigraphic horizons. or round, gray or brown structures (Figs.…”

“…Recently, microfossils were reported in the cap carbonates at two different sections of the Rasthof Formation: Ongongo and Okaaru (Bosak et al, 2011a(Bosak et al, , 2012. The microfossil assemblages from Ongongo and Okaaru contain various abundant agglutinated oval and round three-dimensional rigid and hollow tests whose organic walls are covered by platy, 2-10-mm-long grains of muscovite, microcline, and hematite (Bosak et al, 2011a). The morphologies and compositions of the oval and round tests are consistent with those of modern agglutinated testate amoebae, probably related to the arcellinid amoebozoans (Bosak et al, 2011a).…”

“…The microfossil assemblages from Ongongo and Okaaru contain various abundant agglutinated oval and round three-dimensional rigid and hollow tests whose organic walls are covered by platy, 2-10-mm-long grains of muscovite, microcline, and hematite (Bosak et al, 2011a). The morphologies and compositions of the oval and round tests are consistent with those of modern agglutinated testate amoebae, probably related to the arcellinid amoebozoans (Bosak et al, 2011a). Microbial laminites at Okaaru also preserve rare tubular agglutinated forms and large oval forms with one blunt end, resembling modern monothalamous tubular and globular foraminiferans (Bosak et al, 2011a(Bosak et al, , 2012.…”