Taxonomy Online - Carboniferous spores part I - Species details


Species name
Knoxisporites triradiatus Hoffmeister, Staplin & Malloy, 1955

Description
Radial, trilete, acamerate miospores. Amb subcircular, sometimes rounded triangular. Trilete mark distinct, sutures straight, extending to, or almost to, the equatorial margin of the spore body; sutures accompanied by low, broad, thickened labra. Intexine probably thin; forms inner spore body conformable in outline with the equatorial margin. Exoexine closely adpressed to intexine over proximal and distal surfaces but extended in the equatorial plane to form thick undifferentiated relatively narrow cingulum. Distal surface of exoexine bears thickened, Y-shaped structure with ribs of uniform thickness, extending from the distal pole to fuse with the cingulum in the inter-radial positions.

Other descriptions
Hoffmeister, Staplin & Malloy, 1955, p. 391, pl. 37, figs. 11–12

Size
Overall equatorial diameter 50–88 µm

Remarks
The regular form of the Y-shaped thickening on the distal surface, and the narrow undifferentiated cingulum distinguish this species from others assigned to the genus Knoxisporites. Knoxisporites seniradiatus appears to have thickenings associated with the proximal trilete mark.

Range
Mississippian; Visean to Serpukhovian [Arnsbergian]; TS to SO biozones (Clayton, 1985, and unpublished information)

Images

MPK 7715 MPK 7715 Figure 27a
Shales below Cove Lower Marine Band, Cove Harbour, Berwickshire, Scotland; Visean, NM Biozone, Sample MPA 18247, Specimen MPK 7715. Well-developed uniform cingulum and broad thickened low labra. Distal Y-shaped thickening positioned eccentrically. Specimen maximum dimension 58 µm.


MPK 7718 MPK 7718 Figure 27b
Shales below Cove Lower Marine Band, Cove Harbour, Berwickshire, Scotland; Visean, NM Biozone, Sample MPA 18247, Specimen MPK 7718. Distal focus; clearly defined Y-shaped distal structure and indication of thickened broad labra accompanying trilete mark. Specimen maximum dimension 60 µm.