FIGURE 18. 1–6 in Systematic revision of the trilobite genera Laudonia and Lochmanolenellus (Olenelloidea) from the lower Dyeran (Cambrian Series 2) of western Laurentia

FIGURE 18. 1–6, Bivariate scatterplots depicting intraspecific variation in various aspects of cephalic morphology of Lochmanolenellus subquadratus n. sp. Symbols represent phases of cephalic development. 1, Proportional length of LA. 2, Proportional length of the glabella. 3, Divergence of the ocular lobe from the exsagittal axis. 4, Proportional anterior advancement of the genal spine bases. 5, Orientation of the distal portion of the posterior cephalic margin (distal PCM). 6, Proportional cephalic width, measured as the ratio of the transverse distance between the genal spine bases to glabella length. 7, 8, Bivariate scatterplots depicting intraspecific variation and interspecific disparity in various aspects of cephalic morphology among morphologically mature Lochmanolenellus species. Symbols represent species. 7, Proportional length of the ocular lobes. 8, Cephalic shape, measured as the ratio of the transverse distance between the intergenal spine bases to the transverse distance between the genal spine bases.