Fig. 8 in Crinoid ancestry without blastozoans

Fig. 8. Examples of derived blastozoans with superficial crinoid-like expressions. A. Eocrinoid Rhopalocystis destombesi Ubaghs, 1963 (PE 52747), Early Ordovician of Morocco; lateral view (A1), showing derived superficially camerate-like thecal plating, lacking continuity between "fixed brachial"-like plates and feeding appendages, "rays" tapering, not aligned with ambulacra tips above; oral surface (A2), showing typical biserial blastozoan brachiole facets. B. Diploporite-like blastozoan Eumorphocystis multiporata Branson and Peck, 1940 (TMM 1107TX2), Late Ordovician of Oklahoma, USA; with arm-like appendages superficially similar to crinoids. A ray feeding appendage stub near theca (B1), showing triserial facets, cross-sectional plate shapes and sub-central ovate canal; thecal summit in A-B interray view (B2), showing abrupt boundary between theca and feeding appendages, feeding appendages with thickplated triserial pattern, diplopore-bearing thecal plates; feeding appendage segment with pinnule-like structures (B3). C, D. Paracrinoid, Platycystites sp., Late Ordovician of Oklahoma, USA; oral surfaces of lenticular thecae, sub-ambulacral lumens revealed by natural spalling of brachiole-bearing ambulacrals, in continuity with the peristome. C. NPL 1113TX17, lumens short. D. NPL 1106TX13, lumens long. All Tremadoc crinoids are non-pinnulate.