Fig. 26. Variability and species distinctions of P1 (sp) elements in early Ancyrodella. Scattergrams of density of tuberculation quantified as a ratio of approximated platform area (platform length PL multiplied by its width W) to the number of denticles (except those of carina) and approximated area of the smooth surface on the ventral end of the platform (length of this area S multiplied by its lateral extend E) against element length which serves as an approximation of ontogenetic stage. Three successive samples from Wietrznia are represented by pairs of these scattergrams. That of sample Wtr−7 is A. rotundiloba (Bryant, 1921), sample Wtr−9 represents A. alata (Glenister and Klapper, 1966), and sample Wtr−13 A. rugosa Branson and Mehl, 1934.