Fig. 6 in New insights into the origin and relationships of blastoid echinoderms

Fig. 6. Examples of pan-dichoporite blastozoans. A. The callocystitid Pseudocrinites bifasciatus Pearce, 1843 (BMNH 40189), Wenlock (Silurian), West Midlands, UK, showing the lenticular theca (above) with peripheral ambulacra, the rapidly tapering proximal stem and more cylindrical distal stem (below) terminating in a root structure. B. The rhombiferid Rhombifera sp. (MPZ 2020/590), Late Ordovician, Zaragoza, Spain, showing the stem attached to the theca, which includes the basal, infralateral and base of the lateral plates (above) and one extensive pectinirhomb. C, D. The fissiculate blastoid Codaster acutus McCoy, 1849, early Carboniferous, Yorkshire, UK. C. Oral view of SM E5400 showing the central mouth, five radiating ambulacra, pectinirhomb-like hydrospires, and circular anus (below). D. Polished lateral view of SM E5398 showing basal and radial plates, anus (A) and very thin hydrospire folds (H). E. One branched ambulacrum of the callocystitid Callocystites jewetti Hall, 1852 (ROM 991N), Wenlock (Silurian), Ontario, Canada, showing the ambulacral structure. The mouth is to the left. Brachiole facets (lower branch) are each on a smaller adoral and larger aboral floor plate. Biserial brachioles alternate along the ambulacrum (Br), so main ambulacral axis has double biserial floor plates. F. Stereo images of the coronate Cupulocorona rugosa Donovan and Paul, 1985 (NMW 2013.8G.65i), Late Ordovician, Carmarthen, Wales, showing theca shape and extensive coronal processes (arrow). Top of the small basal plate is displaced. The rest of the theca up to the tip of the coronal process is formed by the "radial" plates. Erect ambulacra arose within the valleys between the coronal processes. G. The hemicosmitoid Hemicosmites extraneus Eichwald, 1840 (GIT 398–898), Late Ordovician, Madise, Estonia. Lateral view (G1) showing, from below, basal, infralateral, lateral, and radial plate circlets. Cryptorhomb pores can be seen in the infralateral and lateral plates. Oral view (G2) showing three large facets for erect ambulacra.