Taxonomy Online - Carboniferous spores part I - Species details


Species name
Cirratriradites saturni (Ibrahim) Schopf, Wilson & Bentall, 1944

Description
Radial, trilete, cingulizonate, camerate miospores. Amb rounded triangular to subcircular. Trilete mark distinct, sutures straight, extending to the equatorial margin of inner body, often obscured by elevated flexuous folds of the exoexine that extend decreasing in height to the equator of spore. Intexine thin, granulate, forming rounded triangular inner body. Exoexine relatively thick, extended in the equatorial plane to form differentially thickened zona consisting of two parts, an inner thickened part which appears to overlap the margin of the inner body on the distal surface and a wider thinner outer part which frequently appears faintly radially striated. Thinner outer section of zona may contain small radially orientated internal vacuoles. Distal exoexine bears prominent foveola in the polar region. Margin of foveola thickened to produce low thickened rim. A single foveola may be present with a circular or ‘clover leaf’ shape. Specimens with up to three separate distal foveolae also occur.

Other descriptions
Smith and Butterworth, 1967, pp. 258–259, pl. 21, figs. 1–2

Size
Overall equatorial diameter 59(73)100 μm. Diameter of inner body 45(58)79 μm

Remarks
Distinguished from other taxa assigned to the genus by the presence of a broad striate zona and one to three distal fovea. Smith and Butterworth (1967) considered that Cirratriradites flabelliformis Wilson & Kosanke was synonymous with C. saturni. C. flabelliformis was originally described as having three foveolae but Smith and Butterworth (1967) provided evidence that complete gradation exists between forms with one to three foveolae.

Range
Late Mississippian to Pennsylvanian; Serpukhovian [Pendleian] to Kazimovian, [Stephanian A (Barruelian)]; NC to ST biozones (Clayton et al., 1977)

Images

MPK 7303 MPK 7303 Figure 7a
Shales above Mousegill Marine Band, Crag House Gill, Stainmore, Cumbria, England; Bashkirian [Kinderscoutian], KV Biozone, Sample CHG la, Specimen MPK 7303. Distal focus. Equatorial outline of miospore and inner body both convexly rounded triangular. Inner body outline obscured by thickened zone. Zona bizonate; inner thicker zone appears to overlap the inner body margin on the distal surface, outer thinner zone radially striated. Distal polar foveola shows evidence of constriction into three components. Specimen maximum dimension 100 μm.


MPK 7304 MPK 7304 Figure 7b
Argill Shell Bed, Argill Beck, Stainmore, Cumbria, England; Bashkirian [Langsettian], RA Biozone, Sample ASB, Specimen MPK 7304. Proximal focus showing strongly bizonate zona. Inner body rounded triangular with indication of separation in the equatorial plane of intexine from exoexine. Trilete sutures extend almost to equatorial margin of inner body, in part obscured by elevated flexuous folds of exoexine, which extend to equatorial margin of spore. Two zones of zona approximately equal in width, outer zone shows faint radial striations and bears fine conate ornament. Distal polar foveola indistinct; suggestion of constriction into three components. Specimen maximum dimension 94 μm.