VALDAR JAANUS SON, SVEN LAUFELD AND ROLAND SKOGLUN D, EDITORS LOWER WENLOCK FAUNAL AND FLORAL DYNAMICS­ VATTENFALLET SECTION, GOTLAND UPPSALA 1979 SVERIGES GEOLO GISKA UN DERSÖKNIN G SERIE C NR 762 AVHANDLINGAR OCH UPPSATSER ÅRSBOK 73 NR 3 VALDAR JAANUSSON, SVEN LAUFELD AND ROLAND SKO GLUN D, EDITORS LOWER WENLOCK FAUNAL AND FLORAL DYNAMICS­ VATTENFALLET SECTION,GOTLAND UPPSALA 1979 ISBN 91-7158- 170-7 Kartan på s. 12 är ur sekretessynpunkt godkänd för spridning. Statens lantmäteriverk 1979-05-28. Fotografiet på s. Il är godkänt för spridning. Försvarsstabens säkerhetsavdelning 1979-05-30. Kristianstads Boktryckeri AB 1979 3 Contents Contributors . 4 Preface VALDAR JAANUSSON, SVEN LAUFELD and ROLAND SKOG- LUND . ... .. ... .. ... 5 Introduction VALDAR JAANUSSON . 7 Stratigraphical and environmental background V AL DAR JAANUSSON . Il Acritarchs FRITZ H. CRAMER, CARMEN DfEZ and GÖ RAN KJELL- STRÖM . .. .. ... .. ... 39 Calcareous algae ROBERT RIDING . 54 Sponges STEFAN BENGTSON . 61 Stromatoporoids HELDUR NESTOR . 63 Foraminifers SVEN LA UFELD . 65 Chitinozoans SVEN LAUFEL D . 70 "Chitinous" hydroids SVEN LAUFELD . 77 Melanosclerites SVEN LAUFELD . 79 Tabulate and heliolitid corals EINAR KLAAMANN . 81 Rugose corals BJÖRN NEDMAN and NILS-MARTIN HANKEN . 86 Polychaete jaws CLAES BERGMAN . 92 Coiled serpulid polychaetes KENT LARSSON . 103 Monoplacophorans JOHN S. PEEL and KRISTINA WÄ NGBERG- ERIKSSON . 104 Polyplacophorans KRISTINA WÄNGBERG-ERIKSSON . 104 Gastropods JOHN S. PEEL and KRISTINA WÄNGBERG-ERIKSSON . 105 Pelecypods JOHN POJET A, Jr. 109 Rostroconchs JOHN POJET A, Jr. 112 Cephalopods HARRY MUTVEI . 113 Trilobites DAVID L. BRUTON, VALDAR JAANUSSON, ROBERT M. OWENS, DEREK J. SIVETER, and RONALD TRIPP . 116 Eurypterids ERIK N. KJELLESVI G-W AERIN G . 121 Phyllocarids W. D. IAN ROLFE . 137 Leperditiid ostracodes ANDERS ANDERSSON . 138 Palaeocope and eridostracan ostracodes DALIP SETHI . 142 Metacope , platycope and podocope ostracodes ROBERT F. LUNDIN . 167 Bryozoans KRISTER BROOD . 172 Coenitids KRISTER BROOD . 181 Allonema (incertae sedis) KRISTER BROOD . 182 Conulariids KRISTER BROOD . 183 Brachiopods MICHAEL G. BASSETT . 185 Tentaculitoids KENT LARSSON . 207 Comulitids KENT LARSSON . 208 Machaeridians STEFAN BENGTSON . 211 Hereolepas (incertae sedis) STEFAN BENGTSON . 212 Graptolites ROLAND SKOGLUND . 213 Echinoderms CHRISTINA FRANZEN . 216 Conodonts LENNART JEPPSSON . 225 Agnathan vertebrates TOR (i')RVIG . 249 Phosphatic tubes STEFAN BENGTSON . 25 1 Organic tubes KRISTER BROOD . 252 Ecology and fauna! dynamics VALDAR JAANUSSON . 253 4 Contributors ANDERSSON, ANDERS, Lunds Universitet, Zoologiska Institutionen, Helgonavägen 3, S- 223 62 Lund, Sweden. BASSETT, MICHAEL G., National Museum of Wales, Department of Geology, Cardiff CFI 3NP, Great Britain. BENGTSON, STEFAN, Uppsala Universitet, Paleobiologiska Avdelningen, Box 564, S- 751 22 Uppsala l, Sweden. BERGMAN, CLAES, Lunds Universitet, Paleontologiska Institutionen, Sölvegatan 13, S- 223 62 Lund, Sweden. BROOD, KRISTER, Naturhistoriska Riksmuseet, Paleozoologiska Sektionen, S-10405 Stock- holm 50, Sweden. BRUTON, DAVID L., Faleontologisk Museum, Sarsgate l, Oslo 5, Norway. CRAMER, FRITZ H., Instituto de Investigaciones Palinol6gicas, Apartado 244, Le6n, Spain. DiE Z, CARMEN, Instituto de lnvestigaciones Palinol6gicas, Apartado 244 , Le6n, Spain. FRANZEN, CHRISTINA, Uppsala Universitet, Paleobiologiska Avdelningen, Box 564, S- 751 22 Uppsala, Sweden. HANKEN, NILS-MARTIN, Universitetet i Oslo, Geologisk Institutt, Avd. C, Blindern, Oslo 3, Norway. JAANUSSON, VALDAR, Naturhistoriska Riksmuseet, Paleozoologiska Sektionen, S- 104 05 Stockholm 50, Sweden. JEPPSSON, LENNART, Lunds Universitet, Paleontologiska Institutionen, Sölvegatan 13, 223 62 Lund, Sweden. KJELLESVIG-WAERING, ERIK N., Waering Exploration Associates, P.O. Box 699, Marco Island, Florida 33937, USA. KJELLSTRÖM, GÖRAN, Sveriges Geologiska Undersökning, Box 670, S-751 28 Uppsala, Sweden. KLAAMANN, EINAR, Eesti NSV Teaduste Akadeemia Geoloogia Instituut, Estonia puiestee 7, 200101 Tallinn, Estonian SSR, USSR. LARSSON, KENT, Sveriges Geologiska Undersökning, Box 670, S-75 1 28 Uppsala, Sweden. LAUFELD, SVEN, Sveriges Geologiska Undersökning, Box 670, S-75 1 28 Uppsala, Sweden. LUNDIN, ROBERT F., Arizona State University, Department of Geology , Tempe, Arizona 85281, USA. MUTVEI, HARRY, Naturhistoriska Riksmuseet, Paleozoologiska Sektionen, S-104 05 Stock­ holm 50, Sweden. NESTOR, HEL DUR, Eesti NSV Teaduste Akadeemia Geoloogia lnstituut, Estonia puiestee 7, 200101 Tallinn,. Estonian SSR, USSR. NEUMAN, BJORN, Universitetet i Bergen, Geologisk Institut!, Avd. A, N-5000 Bergen, Norway. q)RVIG, TOR, Naturhistoriska Riksmuseet, Paleozoologiska Sektionen, S-104 05 Stockholm 50, Sweden. OWENS, ROBERT M., National Museum of Wales, Department of Geology, Cardiff C Fl 3NP, Great Britain. PEEL, JOHN S., Grr,mlands Geologiske Unders'i'Jkelse, 0stervoldgade 10, DK-1350 K'i'Jbenhavn K, Denmark. POJETA, JOHN Jr. , U.S. GeologicaJ Survey, U.S. National Museum, Washington D. C. 20242, USA. RIDING, ROBERT, University College, Department of Geology, P.O. Box 78, Cardiff CFI 1XL, Great Britain. ROLFE, W. D. IAN, The University, Hunterian Museum, Glasgow Gl2 800, Great Britain. SETHI, DALIP, Sveriges Geologiska Undersökning, Box 670, S-751 28 Uppsala, Sweden. SIVETER, DEREK J., Geological Conservatian Review Unit, Pearl House, Barthalornew Street, Newbury, Birkshire RG 14 5LS, U.K. SKOGLUND, ROLAND, Sveriges Geologiska Undersökning, Box 670, S-751 28 Uppsala, Sweden. TRIPP, Ronald, High Wood, Botsom Lane, West Kingsdown, Sevenoaks, Kent TNI5 6BN , Great Britain. WÄNGBERG-ERIKSSON, KRISTINA, Sveriges Geologiska Undersökning, Box 670, S- 751 28 Uppsala, Sweden. 5 Preface lt is increasingly evident that in order to understand the complex relationships affecting the distribution and succession of fossil faunas and floras, our knowledge of local distributional patteros at the species leve! must be consid­ erably expanded. This volume is airned at assessing data from a single section, some 30 m thick, through the latest Llandovery and early Wenlock (Silurian) in Visby on the Swedish island of Gotland. The section, known as Vattenfallet, was collected bed by bed in the early part of this century by G. Liljevall, who amassed over 10,000 macrofossils that form the main basis of this study: all this material, together with other collections (including countless microfossils) has been incorporated in an analysis of fauna! dynamics and general biotic relation­ ships to a degree that has not previously been attempted. In order to achieve the necessary precision at the species leve! a team of 32 specialists from throughout the world has investigated the material to give a reasonably com­ plete coverage of the whole fauna and flora. Their contributions are presented separately for each fo ssil group, and the results are then integrated in an overall analysis of the material. In editing the manuscripts for this volume a great degree of uniformity has had to be imposed on various contributions in order to relate the results in a meaningful way . The s pace available for presentation of the vas t amounts of data has been limited and this has therefore placed some restrictions on the scope of individual contributions. Most manuscripts have had to be cut from their original size, some of them con siderably. Documentation of man y of the species by photographs would have been most desirable, but this would have been unrealistic with regard to the total space available for publication. Only a limited number of new taxa are described and illustrated, mostly those which are important quantitatively and are frequently mentioned in the text. Dr. Michael G. Bassett has undertaken the time-consurning task of linguisti­ cally checking all manuscripts apart from those written by native English­ speaking authors. We are also very much indebted to him for useful editorial suggestions. We thank Mr. Stig Lindbom (Section of Palaeozoology, Riksmuseum) for obtaining samples from Vattenfallet below the base of Liljevall' s section, Mr. Arne Philip (Visby) for aerial photographs of the Vattenfallet area, Dr. Barrie Rickards (Sedgwick Museum, Cambridge) for examining specimens of Thai­ lograptus fr om Högklint d, Dr. Lembit Sarv ( Geoloogia lnstituut, Tallinn) for topotype specimens of various Silurian ostracodes from the East Baltic area, and Dr. Gunnar Svahnström, Landsantikvarie and Head of the Gotland Museum, for the loan of old photographs of Vattenfallet. Most of the illustrations have been drafted by the artists of the Geological Survey of Sweden (SGU), namely Greta Hellström, Ingemar Kj ellberg, Inga 6 Palmaer, and Elin Pulkkinen. A minor part has been prepared at the Section of Palaeozoology, Swedish Museum of Natural History (Naturhistoriska Riks­ museet) by Bo Bergman , Bertil Blueher and Celso Salgueiro . VALDAR JAANUSSON, SVEN LAUFELD and ROLAND SKOGLUND 7 Introduction VALDAR JAANUSSON The seetian at Vattenfallet in the southern outskirts of Visby on Gotland ( Vattenfallsprofilen l, Laufeld 197 4b) has received particular farnethrough the discovery of the scorpion Palaeophonus nuncius (Thorell & Lindström 1885) in the so-called Pterygotus Beds (uppermost 40 cm of the Högklint Limestone). To obtain additional specimens of the scorpion, as weil as eurypterids, these beds were literally quarried over a period of several years at the end of the 19th century. The rich collections assembled, including al so man y other in­ vertebrates, are housed in the