Paul—Testing for homologies in echinoderms


plates. In paracrinoids, both the flooring plates of the main ambulacra and the erect pinnules are uniserial. The flooring plates are again modified first pinnulars but are uniserial simply because pinnules only arise from one side of the ambulacra. Pinnular facets are confined to single flooring plates. More derived ambulacral structures occur where biserial brachioles arise from facets on single flooring plates in a simple biserial arrangement. A variety of ambulacral structures occurs in ‘cystoids.’ Lack of detailed knowledge of such structures in many Cambrian ‘cystoids’ makes it difficult to decide which are likely to be plesiomorphic. Details of any transitions between biserial and uniserial structures are uncertain. Many ambulacral structures conform to the ideal design for


601


Bell, B.M., 1976a, Phylogenetic implications of ontogenetic development in the class Edrioasteroidea (Echinodermata): Journal of Paleontology, v. 50, p. 1001–1019.


Bell, B.M., 1976b,Astudy of North American Edrioasteroidea: New York State Museum, Memoir v. 21, p. 1–447.


Billings, E., 1854, On some new genera and species of Cystidea from the Trenton Limestone: Canadian Journal, v. 2, p. 215–219, 250–253, 268–274.


Billings, E., 1858, Figures and descriptions of Canadian organic remains: Decade 3: Ottawa, Canada, Geological Survey of Canada, 102 p.


Bockelie, J.F., 1978, Variability of ambulacral structures in some diploporite cystoids: Thalassia Jugoslavica, v. 12 (for 1976), p. 31–39.


Bockelie, J.F., 1979a, Celticystis n. gen., a gomphocystitid cystoid from the Silurian of Sweden: Geologiska Föreningens i Stockholm Förhandlingar, v. 101, p. 157–166.


Bockelie, J.F., 1979b, Taxonomy, functional morphology and palaeoecology of the Ordovician cystoid family Hemicosmitidae: Palaeontology, v. 22, p. 363–406.


an efficient filter and match similar structures in modern crinoids. For this and other reasons, ‘cystoids’ probably possessed extensions of the water vascular system in their ambulacra. Cover plates of main ambulacral grooves may not have


opened in life, whereas those of brachioles and pinnules must have done so. There is no evidence for any musculature to open cover plates in either main ambulacral grooves or brachioles and pinnules. The simplest way to open cover plates is by erecting underlying tube feet—another reason for believing extensions of the water vascular system occurred in the ‘cystoid’ ambula- cra. The complete absence of cover plates in the food grooves of Lichenoides and sphaeronitid diploporites is particularly puzzling.


Acknowledgments


I am grateful to A.B. Smith for providing key references and being an inspirational colleague for many years now. S. Zamora, Geological Survey, Spain, kindly provided the original of Figure 13. S. Zamora and I.A. Rahman also furnished some key references. A. Smith and B. Lefebvre produced thorough and thought-provoking reviews of the original manuscript. I amalso indebted to Y. Makhlouf and B. Lefebvre, University Claud Bernard, Lyon, for latex moulds of some critical diploporites originally described by J. Chauvel and J. Barrande, respectively.


Accessibility of supplementary data


Data available from the Dryad Digital Repositary: http://doi.org/ 10.5061/ dryad.n2d7d.


References Angelin, N.P., 1878, Iconographia Crinoideorum in Stratis Sueciae Siluricis Fossilium: Holmiae, 32 p.


Barrande, J., 1846, Note Préliminaire Sur le Systême Silurien et les Trilobites de Bohême: Leipzig, 97 p.


Barrande, J., 1887, Systême Silurien du Centre de la Bohême. Première Partie, Recherches Paléontologiques, v. 7. Classe des Echinodermes, Ordre des Cystidées: Prague, W. Waagen, 233 p.


Bassler, R.S., 1950, New genera of American Middle Ordovician ‘Cystoidea’: Journal of the Washington Academy of Sciences, v. 40, p. 273–277.


Bather, F.A., 1900, The Echinoderma, in Lankester, E.R., ed., A Treatise on Zoology, Part 3: London, A & C Black, 344 p.


Bather, F.A., 1918, Notes on Yunnan cystoids. 2. The species of Sinocystis: Geological Magazine, v. 55, p. 532–540.


Beaver, H.H., 1968, Morphology [of blastoids], in Moore, R.C. ed., Treatise on Invertebrate Paleontology, Part S, Echinodermata 1: Lawrence, Kansas, Geological Society of America and University of Kansas, p. S300–S350.


Bassler, R.S., 1935, The classification of the Edrioasteroidea: Smithsonian Miscellaneous Collections, v. 93, part 8, p. 1–11.


Bockelie, J.F., 1981a, Functional morphology and evolution of the cystoid Echinosphaerites: Lethaia, v. 14, p. 189–202.


Bockelie, J.F., 1981b, The Middle Ordovician of the Oslo Region, Norway, 30. The eocrinoid genera Cryptocrinites, Rhipidocystis and Bockia: Norsk Geologisk Tidsskrift, v. 61, p. 123–147.


Bockelie, J.F., 1981c, A re-evaluation of the Ordovician cystoid Stichocystis Jaekel and the taxonomic implications: Geologiska Föreningens i Stockholm Förhandlingar, v. 103, p. 51–59.


Bockelie, J.F., 1982, Symmetry and ambulacral pattern of the rhombiferan superfamily Caryocystitida and the relationship to other Blastozoa: Geologiska Föreningens i Stockholm Förhandlingar, v. 103, p. 491–498.


Bockelie, J.F., 1984, The Diploporita of the Oslo region, Norway: Palaeontology, v. 27, p. 1–68.


Branson, E.B., and Peck, R.E., 1940, A new cystoid from the Ordovician of Oklahoma: Journal of Paleontology, v. 14, p. 89–92.


Brett, C.E., Frest, T.J., Sprinkle, J., and Clement, C.R., 1983, Coronoidea: Anew class of blastozoan echinoderms based on taxonomic reevaluation of Stephanocrinus: Journal of Paleontology, v. 57, p. 627–651.


Broadhead, T.W., and Strimple, H.L., 1978, Systematics and distribution of the Callocystitidae (Echinodermata, Rhombifera): Journal of Paleontology, v. 52, p. 164–177.


Callaway, C., 1877, On a new area of upper Cambrian rocks in south Shropshire, with a description of a new fauna: Quarterly Journal of the Geological Society, London, v. 33, p. 652–672.


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, v. 11, p. 1–442.


Carpenter, P.H., 1891, On certain points of the morphology of the Cystidea: Journal of the Linnean Society (Zoology), v. 34, p. 1–52.


Chauvel, J., 1941, Recherches sur les Cystoïdes et les Carpoïdes Armoricains: Société Géologique et Minéralogigue de Bretagne, Mémoires, v. 5, p. 1–286.


Chauvel, J., 1966, Échinodermes de l’Ordovicien du Maroc: Cahiers de Paléontologie, (1966), p. 1–120.


Chauvel, J., 1977, Calix sedgwicki Rouault (Échinoderme Cystoïde, Ordovicien du Massif armoricain) et l’appareil ambulacraire des Diploporites: Société Géologique de France, Compte Rendus Sommaires des Séances, 1977, p. 314–317.


Chauvel, J., and le Menn, J., 1979, Sur quelques échinodermes (Cystoïdes et crinoïdes) de l’Ashgill d’Aragon (Espagne): Géobios, v. 12, p. 549–587.


Chen, Z.T., and Yao, J.H., 1993, Palaeozoic Echinoderm Fossils of Western Yunnan, China: Beijing, Geological Publishing House, 102 p. (in Chinese).


Conrad, T.A., 1842, Observations of the Silurian and Devonian systems of the United States, with descriptions of new organic remains: Journal of the Academy of Natural Sciences in Philadelphia, v. 8, p. 183–190.


David, B., and Mooi, R., 1998, Major events in the evolution of echinoderms viewed in the light of embryology, in Mooi, R., and Telford, M., eds., Echinoderms, San Francisco: Rotterdam, Balkema, p. 21–28.


Derstler, K.L., 1981, Morphological diversity of early Cambrian echinoderms, in Taylor, M.E., ed., Short Papers for the Second International Symposium on the Cambrian System: United States Open File Report, 81-743, p. 71–75.


Donovan, S.K., and Paul, C.R.C., 1985, Coronate echinoderms from the lower Palaeozoic of Britain: Palaeontology, v. 28, p. 527–543.


Durham, J.W., 1967, Notes on the Helicoplacoidea and early echinoderms: Journal of Paleontology, v. 41, p. 97–102.


Durham, J.W., and Caster, K.E., 1963, Helicoplacoidea: A new class of echinoderms: Science, v. 140, p. 820–822.


Eichwald, E. von, 1840, Ueber das silurische Schichtensystem in Esthland: Zeitschrift für Natur- und Heilkunde der medizinischen Akademie zu St Petersburg, v. 1, p. 1–222 (also published in French).


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212  |  Page 213  |  Page 214  |  Page 215  |  Page 216  |  Page 217  |  Page 218  |  Page 219  |  Page 220  |  Page 221  |  Page 222  |  Page 223  |  Page 224  |  Page 225  |  Page 226  |  Page 227  |  Page 228  |  Page 229  |  Page 230  |  Page 231  |  Page 232  |  Page 233  |  Page 234  |  Page 235  |  Page 236  |  Page 237  |  Page 238  |  Page 239  |  Page 240  |  Page 241  |  Page 242  |  Page 243  |  Page 244  |  Page 245  |  Page 246  |  Page 247  |  Page 248  |  Page 249  |  Page 250  |  Page 251  |  Page 252  |  Page 253  |  Page 254  |  Page 255  |  Page 256  |  Page 257  |  Page 258  |  Page 259  |  Page 260  |  Page 261  |  Page 262  |  Page 263  |  Page 264  |  Page 265  |  Page 266  |  Page 267  |  Page 268  |  Page 269  |  Page 270  |  Page 271  |  Page 272  |  Page 273  |  Page 274  |  Page 275  |  Page 276  |  Page 277  |  Page 278  |  Page 279  |  Page 280  |  Page 281  |  Page 282  |  Page 283  |  Page 284  |  Page 285  |  Page 286  |  Page 287  |  Page 288