Table 29.2.

Character scoring for spore disparity index

1. Amb shape
 Circular–subcircular–subtriangular (1); ellipsoid (monolete only) (1); triangular (2); triangular convex (3); triangular concave (3); triangular truncated (3)
2. Amb size
 0–50 μm (1); 50–100 μm (2); 100–200 μm (3); >200 μm (4)
3. Structure
 Crassitate (1); retusoid (2); patinate (2); cingulate (2); zonate (3); bilayered-perine or sloughing outer layer (3); camerate (4)
4. Tetrad configuration
 Trilete (1); monolete (2)
5. Laesurae
 Simple (1); prominent lips (2)
6. Proximal structural features
 None (1); interradial papillae (2); thickening associated with trilete mark (2); thinning associated with trilete mark (2); radial ribs (3); radial ribs and thickening associated with trilete (4)
7. Proximal ornament
 Laevigate (1); irregular murornate (2); irregular apiculate (2); irregular fovea (2); regular murornate (3); regular apiculate (3); regular reticulate (3); regular foveolate (3); biform (4); complex elements (4)
8. Distal structural features
 None (1); circular thickening (2); infrastructure (proximal and/or distal) (2); annular thickening (3)
9. Distal ornament
 Laevigate (1); irregular murornate (2); irregular apiculate (2); irregular fovea (2); regular murornate (3); regular apiculate (3); regular reticulate (3); regular foveolate (3); biform elements (4); reticulate with extended intersections (4); complex elements (e.g. grapnel-tipped) (5)
  • Each spore is scored for each of the nine morphological components listed above. These are summed to provide the ‘spore disparity index’. Scores within each of the nine morphological components are intended to reflect morphological complexity, rather than order of appearance in the fossil record. We have attempted to consider their complexity within a developmental context (i.e. how easy they are to construct in terms of exospore development).