Glyptosphaerites is a stemless, directly attached diploporite characterized by five ambulacra that have multiple facets and extend over the theca, but entirely lack flooring and cover plates. The food grooves lack any systematic relationship to the underlying thecal plates and grew out from a mouth with a frame of six plates; five radial circumorals and a sixth interradial plate in the CD interambulacrum. The mouth was covered by a palate of eleven palatal plates. These characters are shared by most Sphaeronitidae, whereas traditionally Glyptosphaerites has been associated with diploporites that possess a stem and ambulacra with biserial flooring plates that alternate, left and right, and each of which supports a single brachiole facet. Such diploporites are characterized by Protocrinites, which has cover plates over its ambulacra and mouth but lacks a palate. Glyptosphaerites and Protocrinites are typical of two major divisions within the Diploporita, here called the Anambulacralia and Ambulacralia, respectively. The oldest identified anambulacralian is the middle Cambrian ‘eocrinoid’ Lichenoides.
Diplopores of Glyptosphaerites leuchtenbergi arose on plate sutures as a single perpendicular canal like an epispire. This became incorporated into one plate as a second perpendicular canal developed on the suture. Further plate growth increased the separation of the two perpendicular canals until a standard distance was established when both canals became incorporated into the plate. Thus, the axes connecting perpendicular canals are perpendicular to plate sutures. In G. leuchtenbergi, diplopores were preferentially incorporated into one plate, often resulting in diplopores being concentrated in the adoral halves of thecal plates.
Alvaró, J. J., Gutiérrez-Marco, J. C. & Zamora, S. 2015. Early Paleozoic faunas from the Luna Valley. In Progress in Echinoderm Palaeobiology (Zamora, S. & Rábano, I., eds), Cuardenos del Museo Geominero, 19, 249–260.
Angelin, N. P. 1878. Iconographia Crinoideorum in stratis Sueciae Siluricis fossilium. Holmiae, Stockholm, iv + 62 pp.
Barrande, J. 1846. Notice préliminaire sur le Systême Silurien et les trilobites de Bohême. Hirshfeld, Leipzig, vi + 97 pp.
https://doi.org/10.5962/bhl.title.9142
Barrande, J. 1887. Systême Silurien du centre de la Bohême. Premier Partie: Recherches paléontologiques. Vol. 7, Classe des Échinodermes. Ordre des Cystidés. W. Waagen, Prague, xix+233 pp.
Bernard, F. 1893–1895. Eléments de Paléontologie. J.-B. Ballière et Fils, Paris, viii + 1168 pp.
Bockelie, J. F. 1979. Celticystis n. gen., a gomphocystitid cystoid from the Silurian of Sweden. Geologiska Föreningens i Stockholm Förhandlingar, 101, 157–166.
https://doi.org/10.1080/11035897909452575
Bockelie, J. F. 1984. The Diploporita of the Oslo region, Norway. Palaeontology, 27, 1–68.
Branson, E. B. & Peck, R. E. 1940. A new cystoid from the Ordovician of Oklahoma. Journal of Paleontology, 14, 89–92.
Carpenter, P. H. 1884. Report upon the Crinoidea collected during the voyage of HMS Challenger during the years 1873–76, part 1. General morphology with descriptions of the stalked crinoids. Reports of the Scientific Results of the Voyage of HMS Challenger, Zoology, 11, 1–442.
https://doi.org/10.5962/bhl.title.11805
Carpenter, P. H. 1891. On certain points of the morphology of the Cystidea. Journal of the Linnean Society (Zoology), 34, 1–52.
https://doi.org/10.1111/j.1096-3642.1891.tb02474.x
Colmenar, J., Villas, E., Gutiérrez-Marco, J. C. & Zamora, S. 2015. Ordovician to Devonian echinoderm faunas from the Iberian chains. In Progress in Echinoderm Palaeobiology (Zamora, S. & Rábano, I., eds), Cuardenos del Museo Geominero, 19, 231–246.
David, B. & Mooi, R. 1998. Major events in the evolution of echinoderms viewed by the light of embryology. In Echinoderms: San Francisco (Mooi, R. & Telford, M., eds), pp. 21–28. Balkema, Rotterdam.
David, B., Mooi, R. & Telford, M. 1995. The ontogenetic basis of Lovén’s Rule clarifies homologies of the echinoid peristome. In Echinoderm Research(Emson, R. H., Smith, A. B. & Campbell, A., eds), pp. 155–164. Balkema, Rotterdam.
Eichwald, E. 1840. Sur le systême silurien de l’Esthonie. St. Petersburg, 1, 222 pp.
Eichwald, E. 1856. Beitrag zur geographischen Verbreitung der fossilien Thiere Russlands. Alte Periode. Bulletin de la Société Impériale des Naturalistes de Moscou, 29, 88–127.
Eichwald, E. 1860. Lethaea Rossica ou Paléontologie de la Russie, décrite et figurée. Premier volume. Seconde Section de l’ancienne Période en deux sections. E. Schweizerbart, Stuttgart, XIX+1–1657 pp.
Foerste, A. F. 1914. Notes on Agelacrinidae and Lepadocystinae with descriptions of Thresherodiscus and Brockocystis. Bulletin of the Scientific Laboratories of Denison University, 17, 399–487.
Frest, T. J. 1983. Systematics and paleoecology of new Holocystites fauna taxa (Echinodermata, Blastozoa: Diploprita) from the Wenlockian (Silurian) of Indiana. Chapter 7. In Studies of Silurian Echinoderms. Unpublished Ph D thesis, University of Iowa.
Frest, T. J., Strimple, H. L. & Paul, C. R. C. 2011. The North American Holocystites fauna (Echinodermata: Blastozoa: Diploporita): paleobiology and systematics. Bulletins of American Paleontology, 380, 1–142.
Guensburg, T. E., Sprinkle, J., Mooi, R. & Lefebvre, B. 2021. Evolutionary significance of the blastozoan Eumorphocystis and its pseudo-arms. Journal of Paleontology, 95, 327–343.
https://doi.org/10.1017/jpa.2020.84
Hisinger, W. 1828. Anteckningar i Physik och Geognosi under resor uti Sverige och Norrige. Vol. 4, Stockholm, x + 258 pp.
Jaekel, O. 1899. Stammesgeschichte der pelmatozoen. 1. Thecoidea und Cystoidea. Julius Springer: Berlin; 442 pp.
https://doi.org/10.5962/bhl.title.8521
Jaekel, O. 1918. Phylogenie und System der Pelmatozoen. Paläontologisches Zeitschrift, 3, 1–128.
https://doi.org/10.1007/BF03190413
Jaekel, O. 1926. Über zwei Cystoideen und ihre morphologische Bewertung. Norsk Geologisk Tiddskrift, 9, 19–22.
Kesling, R. V. 1968. Cystoids. In Treatise on Invertebrate Paleontology, Part S, Echinodermata 1 (1) (Moore, R. C., ed.), pp. S85–S267. Geological Society of America and University of Kansas: New York and Lawrence.
Kröger, B. & Aubrechtová, M. 2019. The cephalopods of the Kullsberg Limestone Formation, Upper Ordovician, central Sweden and the effects of reef diversification on cephalopod diversity. Journal of Systematic Palaeontology, 17, 961–995.
https://doi.org/10.1080/14772019.2018.1491899
Lefebvre, B, Ghobadipour, M. & Nardin, E. 2005. Ordovician echinoderms from the Tabas and Damghan regions, Iran: palaeobiogeograhical implications. Bulletin de la Société Géologique de France, 176, 231–242.
https://doi.org/10.2113/176.3.231
Meléndez, B. 1944. Nuevos datos para le estratigrafia del Paleozoico aragonés. Boletín de la Real Sociedad Española de Historia Natural, 42, 129–150.
Mergl, M. & Prokop, R. J. 2006. Lower Ordovician cystoids (Diploporita, Rhombifera) from the Prague Basin (Czech Republic). Bulletin of Geosciences, 81, 1–15.
https://doi.org/10.3140/bull.geosci.2006.01.001
Mooi, R. & David, B. 1997. Skeletal homologies of echinoderms. In Geobiology of Echinoderms (Waters, J. A. & Maples., C. G., eds), Paleontological Society Papers, 3, 305–335.
https://doi.org/10.1017/S1089332600000310
Müller, J. 1854. Über den Bau der Echinodermen. Abhandlungen der königlichen preussischen Akademie der Wissenschaften, aus dem Jahre 1853, 123–219.
Neumayr, M. 1889. Die Stämme des Thierreiches. 1. Wirbellose Thiere. Tempsky, Vienna and Prague, 603 pp.
Parsley, R. L. 1982. Eumorphocystis. In Echinoderm Faunas from the Bromide Formation (Middle Ordovician) of Oklahoma (Sprinkle, J., ed.), University of Kansas Paleontological Contributions, Monograph, 1, 280–288.
Paul, C. R. C. 1971. Revision of the Holocystites fauna (Diploporita) of North America. Fieldiana: Geology, 24, 1–166.
https://doi.org/10.5962/bhl.title.3412
Paul, C. R. C. 1972. Morphology and function of exothecal pore-structures in cystoids. Palaeontology, 15, 1–28.
Paul, C. R. C. 1973. British Ordovician Cystoids, part 1. Monographs of the Palaeontographical Society, 127(536), 1–64.
Paul, C. R. C. 1984. British Ordovician Cystoids, part 2 Monographs of the Palaeontographical Society, 136(563), 65–152.
Paul, C. R. C. 1988. The phylogeny of the cystoids. In Echinoderm Phylogeny and Evolutionary Biology (Paul, C. R. C. & Smith, A. B., eds), pp. 199–213. Oxford Science Publications, Oxford.
Paul, C. R. C. 1997. Second addendum to Part 1. British Ordovician Cystoids, part 3. Monographs of the Palaeontographical Society, 151(604), 153–155.
Paul, C. R. C. 2017. Testing for homologies in the axial skeleton of primitive echinoderms. Journal of Paleontology, 91, 582–603.
https://doi.org/10.1017/jpa.2016.151
Paul, C. R. C. 2018. Prokopius, a new name for “Hippocystis sculptus” Prokop, 1965 and the status of the genus Hippocystis Bather, 1919 (Echinodermata; Diploporita). Bulletin of Geosciences, 93, 337–346.
https://doi.org/10.3140/bull.geosci.1697
Paul, C. R. C. & Fone, W. 1997. Third addendum to Part 1. British Ordovician Cystoids, part 3. Monographs of the Palaeontographical Society, 151(604), 155–159.
Paul, C. R. C. & Gutiérrez-Marco, J. C. 2020. Enodicalix (Diploporita, Aristocystitidae), a new echinoderm genus from the Middle Ordovician of Spain. Geologica Acta, 18.3, 1–8.
https://doi.org/10.1344/GeologicaActa2020.18.3
Paul, C. R. C. & Hotchkiss, F. R. C. 2020. Origin and significance of Lovén’s Law in echinoderms. Journal of Paleontology, 94, 1089–1102.
https://doi.org/10.1017/jpa.2020.31
Paul, C. R. C. & Toom, U. 2021. Cystoblastus and the origin of the Hemicosmitoida (Echinodermata: Blastozoa). Estonian Journal of Earth Sciences, 70, 165–181.
https://doi.org/10.3176/earth.2021.13
Prokop, R. J. 1964. Sphaeronitoidea Neumayr of the Lower Palaeozoic of Bohemia (Cystoidea, Diploporita). Sborník Geologických věd, Paleontologie, 3, 7–37.
Prokop, R. J. & Petr, V. 1999. Echinoderms in the Bohemian Ordovician. Journal of the Czech Geological Society, 44, 63–68.
Regnéll, G. 1945. Non-crinoid Pelmatozoa from the Paleozoic of Sweden. A taxonomic study. Meddelanden från Lunds Geologisk-Mineralogiska Institution, 108, 1–255.
Sheffield, S. L. & Sumrall, C. D. 2019a. A re-interpretation of the ambulacral system of Eumorphocystis (Blastozoa, Echinodermata) and its bearing on the evolution of early crinoids. Palaeontology, 61, 163–173.
https://doi.org/10.1111/pala.12396
Sheffield, S. L. & Sumrall, C. D. 2019b. The phylogeny of the Diploporita: a polyphyletic assemblage of blastozoan echinoderms. Journal of Paleontology, 93, 740–752.
https://doi.org/10.1017/jpa.2019.2
Smith, A. B. 1980. Stereom microstructure of the echinoid test. Special Papers in Palaeontology, 25, 1–81.
Sprinkle, J. 1973. Morphology and evolution of blastozoan echinoderms. Special Publication, Museum of Comparative Zoology, Harvard, 1–284.
https://doi.org/10.5962/bhl.title.66379
Sprinkle, J. & Guensburg, T. E. 2001. Growing a stalked echinoderm within the Extraxial-Axial Theory. In Echinoderms 2000 (Barker, M. F., ed.), pp. 59–65. A. A. Balkema, Lisse.
Sumrall, C. D. & Gahn, F. J. 2003. The phylogenetic position and morphological reinterpretation of two enigmatic edrioasteroids from Canada. Geological Society of America, Abstracts with Programs, 35(6), 165.
Sumrall, C. D. & Gahn, F. J. 2006. Morphological and systematic reinterpretation of two enigmatic edrioasteroids (Echinodermata) from Canada. Canadian Journal of Earth Sciences, 43, 497–507.
https://doi.org/10.1139/e05-114
Sumrall, C. D., Sprinkle, J. & Guensburg, T. E. 2001. Comparison of flattened blastozoan echinoderms: insights from the new early Ordovician eocrinoid Haimacystis rozhnovi. Journal of Paleontology, 75, 985–992.
https://doi.org/10.1017/S0022336000039895
Thomka, J. R. & Brett, C. E. 2014. Diploporite (Echinodermata: Blastozoa) thecal attachment structures from the Silurian of southeastern Indiana. Journal of Paleontology, 88, 179–186.
https://doi.org/10.1666/12-142
Ubaghs, G. 1953. Notes sur Lichenoides priscus Barrande, eocrinoïde du Cambrien Moyen de la Tchécoslovaquie. Bulletin de l’Institut royal des Sciences Naturelles de Belgique, 29, 1–24.
Ubaghs, G. 1968. Eocrinoidea. In Treatise on Invertebrate Paleontology, Part S Echinodermata 1 (Moore, R. C., ed.), pp. S455–S495. Geological Society of America and University of Kansas: New York and Lawrence.
Volborth, A. von 1846. Über die russischen Sphaeroniten, eingeleitet durch einige Betrachtungen über die Arme der Cystideen. Verhandlungen Russisch-Kaiserlichen Mineralogischen Gesellschaft zu St. Petersburg, 1845–1846, 161– 198.
