Figure 5 Boxplots of measurements of Agaricocrinus , Aorocrinus , and Dorycrinus . Box widths are proportional to the square root of the number of specimens in each time bin. A, Plate width/calyx diameter of Agaricocrinus (time bins 3, 4

Table 3 Variance of trait distributions in each time bin for convexity values in Agaricocrinus and spine length values in Aorocrinus and Dorycrinus. Spine length values rounded to two decimal places in Dorycrinus and four decimal places in Aorocrinus.

Figure 6 Boxplots of spine measurements for Aorocrinus and Dorycrinus . Box widths are proportional to the square root of the number of specimens in each time bin. A, Spine width/calyx diameter for Aorocrinus central spine base (time bins 1, 3, 4, and 6). B

T able 2 Measurements for Aorocrinus (in mm, * incomplete or specimen compacted, ** holotype).

Table 3 —Measurements of Aorocrinus nodulus n. sp. (in mm); holotype indicated by asterisk

Figure 1 Drawings of Dorycrinus cornigerus (A, B), Aorocrinus subaculeatus (C), and Agaricocrinus americanus (D, E). From Wachsmuth and Springer ( 1897 ).

diameter of Aorocrinus (time bins 1, 3, 4, and 6). D, Dorycrinus spine length/calyx diameter of central spine (time bins 3, 4, and 6). E, Dorycrinus spine length/calyx diameter of C-ray spine (time bins 3, 4, and 6). F, Dorycrinus spine length

F igure 8 Histograms indicating frequency of free arm number per ray among 47 specimens of Aorocrinus helice in the CMCIP collections.

Table 2 Range of trait value distributions in each time bin for convexity values in Agaricocrinus and spine length values in Aorocrinus and Dorycrinus. Spine length values rounded to two decimal places.

T able 3 Statistics from consideration of allometry in Aorocrinus helice. H = height; W = width; BP = basal plate; BC = basal circlet; RP = radial plate; Pr1 = first primibrachial. Shaded regions indicate allometry.

T able 5 Statistics from consideration of allometry in Aorocrinus helice. H = height; W = width; BP = basal plate; BC = basal circlet; RP = radial plate; Pr1 = first primibrachial. Shaded area indicates allometry.

Table 1 Results of Mann-Whitney U -tests comparing distributions of trait values for plate convexity and plate width in Agaricocrinus , spine length and spine width in Aorocrinus and Dorycrinus , and calyx diameter in all three genera. Boldface

F igure 6 Aorocrinus from the Cuyahoga Formation. 1–8, A. helice (1863b): 1 , lateral view of crown, lectotype, NYSM 6119 (previously illustrated in Hall and Whitfield, 1875 , pl. 11, fig. 6), ×1.5; 2 , CD-interray view of crown, paralectotype, NYSM 6120 (previously illustrated in Hall

F igure 7 Aorocrinus helice (Hall, 1863b), Platycrinites s.l. graphicus (Hall, 1863b), and Platycrinites s.l. lodensis ( Hall and Whitfield, 1875 ). 1 , 4–6 , A. helice: 1 , plate diagram (A–E ray designations, P. indicates primanal, gray indicates depressions on calyx); 4–6 , (black, radial

Figure 1 —Nada Member crinoids. 1–4, Aorocrinus nodulus n. sp., ×3.0; holotype, 1, 2, OSU 50373, 1, CD-interray view; 2, A-ray lateral view; 3, 4, paratype, OSU 50376, 3, basal view; 4, oral view. 5–7, Blairocrinus protuberatus n. sp.; ×2.0, 5, 6, holotype, OSU 50379, 5

APPENDIX Taphonomic data used in this study. Strat: stratigraphic provenance of specimens as in Figure 1 ; Group: crinoid group to which specimens belong as in Figure 8 ; Genus: Ab, Abatocrinus ; Ao, Aorocrinus ; Ap, Aphelecrinus ; Be, Belemnocrinus ; Bl, Blothrocrinus ; Cr, Cribanocrinus