(Waltz) Hacquebard & Barss, 1957
Radial, trilete, cingulate miospores. Amb circular to subcircular. Trilete mark distinct, sutures straight, extending almost to spore body margin, accompanied by broad, flat labra, extending 6–10 µm on either side of the sutures and having undulate outer margins. Intexine laevigate to infrapunctate, forms circular to subcircular inner body. Exoexine extended in the equatorial plane to form smooth dense cingulum surrounded by more transparent, less robust, equatorial border which has a frilled membranous appearance. Boundary between the two parts of the cingulum is smooth. In some specimens outer membranous part of the cingulum appears to overlap thicker inner part particularly on the distal surface. Thinner outer membranous section may be variable in width creating undulate equatorial margin.
Hacquebard and Barss, 1957, p. 28, pl. 4, fig. 2 .
Playford, 1962, pp. 632–633, pl. 90, figs. 1–3
Overall equatorial diameter 90(115)144 µm.
Diameter of the inner body 50(69)88 µm
Playford (1963) pointed out that those specimens in which the thinner membranous zone of the cingulum has been partly removed appear as transitional forms with Anulatisporites labiatus
Hughes & Playford 1961, which has a smooth undifferentiated cingulum.
Mississippian; Tournaisian to Visean (Playford, 1962)
MPK 7257 Figure 31a
Mattson Formation, south face of Twisted Mountain, north-west of South Nahanni, Northwest Territories, Canada; Visean, MA Biozone (Playford, 1962), Sample MATT, Specimen MPK 7257. Proximal focus. Subcircular inner body with open trilete mark, sutures extending approximately three-quarters of body radius, accompanied by broad, low, thickened labra. Note evidence of separation between intexine and exoexine in the equatorial plane. Bizonate cingulum has ill-defined junction between inner thicker and outer thinner sections. Exine surface infrapunctate.
Specimen maximum dimension 109 µm.
MPK 7259 Figure 31b
Mattson Formation, south face of Twisted Mountain, north-west of South Nahanni, Northwest Territories, Canada; Visean, MA Biozone (Playford, 1962), Sample MATT, Specimen MPK 7259. Trilete mark slightly open but clearly accompanied by broad, low, thickened labra with crenulate outer margins.
Specimen maximum dimension 101 µm.