Samtlebenella circumcamerata

Hussain, Rowshi, Rogers, Steven L. & Blackburn, Joel A., 2022, Ovummuridae (calcareous microfossils) from the Much Wenlock Limestone Formation, Shropshire, UK, Palaeontologia Electronica (a 27) 25 (2), pp. 1-24 : 10-12

Samtlebenella circumcamerata

Munnecke, Servais, and Vachard, 2000

Figure 5 G-H

Derivation of name. Latin, circum, around; camera, vault, chamber.

Material. 5 specimens

Original diagnosis. A species of Samtlebenella with 10-15 chamberlets regularly distributed in the wall.

Dimensions. Munnecke et al. (2000) noted total lengths of S. circumcamerata to measure between 80–125 µm, and the total width between 50–120 µm and observed between 10–15 chamberlets. Our specimens measure: overall lengths of 84–185 µm and diameters of 96–173 µm with only 1-4 chamberlets observed. The thickness of the wall is noted to vary between 4–27 µm.

Remarks. Specimens are undetermined if they are Samtlebenella circumcamerata as the chambers within the walls are not clear due to their small sizes and possibly could be juvenile specimens. Observations of 1-4 chamberlets only but could be due to cross-sectional cuts. We note specimens of a larger size than those observed at Gotland.

Stratigraphical range. Lower Silurian (Homerian)

Figures

FIGURE 5. Photomicrographs of Arouxina pluricellata (A-F) and Samtlebenella circumcamerata (G-H) within the MWL Fm., these specimens are from Longville Stanway Track (A), Moorwood Quarry (B, C, E and H), Harton Hollow (D and G) and Strefford Quarry (H). (A) = Sectional cut through A. pluricellata highlighting the multiple hemispherical chambers (HC) surrounding the globular dorsal chamber (DC) and ventral chamber (VC). HC can form concentrically. Occasional apical apertures (ap) are observed within the DC.The bulbous growth are associated with several walls. (B) = Thickened A. pluricellata specimen with six HC surrounding the central DC and VC. Note the presence of pyrite within a few of the HC. Matrix comprised solely of sparite. (C) = An elongate A. pluricellata test with three HC. (D) = Specimen of A. pluricellata highlighting the disjointed nature of the surrounding HC. (E) = A. pluricellata with a single HC chamber but exhibits an ap within both VC and DC. (F) = A. pluricellata specimen with thinner walled HC compared to the walls surrounding the DC and VC. (G) = S. circumcamerata resembling Darth Vader’s helmet. Presence of HC within the walls surrounding the DC. (H) = Thick walled specimen of S. circumcamerata with a partially preserved VC and two chambers (c) are visible within the walls surrounding the DC. Sparitic matrix = (sp). All scale bars equal 50 µm.