Taxonomy Online - Carboniferous spores part I - Species details


Species name
Convolutispora major (Kedo) Turnau, 1978

Description
Radial, trilete miospores. Amb rounded triangular to subcircular, equatorial margin undulate. Trilete mark distinct to indistinct; often obscured by ornamentation. Sutures straight, accompanied by low broad labra, up to 8 µm wide, extending at least 50 % of spore radius and sometimes reaching almost to equatorial margin. Exine up to 11 µm thick (including ornament). Distal surface and more equatorial portion of proximal surface ornamented by dense irregular, imperfect reticulum of anastomosing variably thickened ridges, individual ridges 6–10 µm wide, 6 µm high, rounded in profile. Lumina irregular, branched, 3–10 µm wide. Ridges on equatorial portion of proximal surface shorter and occasionally wart-like. Contact areas often smooth.

Other descriptions
Turnau, 1978, p. 8, pl. 2, figs. 18a, b and 19

Size
Equatorial diameter 69(95)119 µm

Remarks
The coarse ornament of convolute ridges forming an imperfect reticulum distinguishes this species from others assigned to Convolutispora. Convolutispora harlandi Playford 1962 has coarse convolute ridges but these are irregularly and densely arranged and do not form a reticulum. C. labiata Playford 1962 has similar broad, low, thickened labra accompanying the trilete sutures, but differs from C. major in possessing an ornament of fine convolute ridges.

Range
Mississippian; Tournaisian (Turnau, 1978).

Images

MPK 7192 MPK 7192 Figure 10a
Bialy Bor No.1 Borehole, 2788.8 m, west Pomerania, Poland; Mississippian, Tournaisian, Ma Biozone, Sample MPA 33201/1, Specimen MPK 7192. Subcircular thick walled miospore with dense ornament of coarse irregular ridges that anastomose to form loose reticulate pattern. Projecting ridges in equatorial region produce undulate margin of spore. Specimen maximum dimension 82 µm.


MPK 7197 MPK 7197 Figure 10b
Bialy Bor No.1 Borehole, 2788.8 m, west Pomerania, Poland; Mississippian, Tournaisian, Ma Biozone, Sample MPA 33201/2, Specimen MPK 7197. Specimen maximum dimension 115 µm.