In this work, previously published occurrences of vertebrates from the latest Llandovery to end-Ludlow successions of Gotland, Sweden, are gathered and summarized in an updated stratigraphic framework, which also incorporates facies differences of sedimentary units. Even though the taxonomy of vertebrates from Gotland is in need of revision, their occurrences are here reported on a group level in order to give preliminary indications of where the focus of continued sampling should lie. Indeed, there are parts of Gotland that are poorly represented by the samples at hand and others that have been extensively sampled but still have not yielded any vertebrates. Preliminary investigations of new samples indicate that the lack of vertebrates in older sediments of Gotland may be because of sampling bias, while the reasons for a complete absence of vertebrates in other parts remain unknown. Our results also emphasize a sudden appearance of acanthodians on Gotland in the early Ludfordian. To investigate these preliminary results, complementary sampling and more confined facies-categorization will be needed. Combined with a higher taxonomical resolution, this will also help us understand how the vertebrate faunas were affected by the events coupled with extinctions that have been identified on Gotland and on a global scale. One of these events has been shown to affect the Gotland vertebrates before. Our results indicate that this may be true for several of the events. When an increased understanding of the vertebrate faunas of Gotland has been established, the goal is to use up-to-date correlations to compare Gotland with other parts of the Baltic Basin to render a better picture of early vertebrate evolution during the Silurian.
Blom, H., Märss, T. & Miller, G. C. 2002 (for 2001). Silurian and earliest Devonian birkeniid anaspids from the Northern Hemisphere. Transactions of the Royal Society of Edinburgh: Earth Science, 92, 263–323.
Calner, M. 1999. Stratigraphy, facies development, and depositional dynamics of the Late Wenlock Fröjel Formation, Gotland, Sweden. GFF, 121, 13–24.
http://dx.doi.org/10.1080/11035899901211013
Calner, M. & Säll, E. 1999. Transgressive oolites onlapping a Silurian rocky shoreline unconformity, Gotland, Sweden. GFF, 121, 91–100.
http://dx.doi.org/10.1080/11035899901212091
Calner, M., Jeppsson, L. & Eriksson, M. J. 2004a. Ytterholmen revisited – implications for the Late Wenlock stratigraphy of Gotland and coeval extinctions. GFF, 126, 231–241.
http://dx.doi.org/10.1080/11035890401262231
Calner, M., Jeppsson, L. & Munnecke, A. 2004b. The Silurian of Gotland–Part I: Review of the stratigraphic framework, event stratigraphy, and stable carbon and oxygen isotope development. In Early Palaeozoic Palaeogeographic and Palaeoclimate (IGCP 503), Abstract and Field Guides (Munnecke, A., Servais, T. & Schulbert, C., eds), Erlanger Geologische Abhandlungen, Sonderband, 5, 113–131.
Eriksson, M. E. & Calner, M. 2005. The Dynamic Silurian Earth. Sveriges Geologiska Undersökning, Rapporter och Meddelanden, 121, 1–99.
Eriksson, M. E., Nilsson, E. K. & Jeppsson, L. 2009. Vertebrate extinctions and reorganizations during the Late Silurian Lau Event. Geology, 37, 739–742.
http://dx.doi.org/10.1130/G25709A.1
Erlström, M., Persson, L., Sivhed, U. & Wickström, L. 2009. Beskriving till regional berggrundskarta över Gotlands län [Description to regional bedrock map of Gotland county]. Sveriges Geologiska Undersökning, K221, 60 pp. [in Swedish].
Fredholm, D. 1988a. Vertebrates in the Ludlovian Hemse Beds of Gotland, Sweden. GFF, 110, 157–179.
http://dx.doi.org/10.1080/11035898809452655
Fredholm, D. 1988b. Vertebrate biostratigraphy of the Ludlovian Hemse Beds of Gotland, Sweden. GFF, 110, 237–253.
http://dx.doi.org/10.1080/11035898809455448
Fredholm, D. 1989. Silurian vertebrates of Gotland, Sweden. PhD thesis. Lund Publications in Geology, 76, 1–47.
Fredholm, D. 1990. Agnathan vertebrates in the Lower Silurian of Gotland, Sweden. GFF, 112, 61–84.
http://dx.doi.org/10.1080/11035899009453162
Gross, W. 1968a. Die Agnathen-Fauna der silurischen Halla-Schichten Gotlands. GFF, 90, 369–400.
http://dx.doi.org/10.1080/11035896809448410
Gross, W. 1968b. Fragliche actinopterygier-schuppen aus dem Silur Gotlands. Lethaia, 1, 184–218.
http://dx.doi.org/10.1111/j.1502-3931.1968.tb01736.x
Janvier, P. 1971. Nouveau matériel de Andreolepis hedei Gross, Actinoptérygien énigmatique du Silurien de Gotland (Suède). Comptes Rendus de l’Académie des Sciences, Paris, 273, 2223–2224.
Janvier, P. 1978. On the oldest known teleostome fish, Andreolepis hedei Gross (Ludlow of Gotland), and the systematic position of the lophosteids. Eesti NSV Teaduste Akadeemia Toimetised, Geoloogia, 27, 88–95.
Jeppsson, L. 1993. Silurian events: the theory and the conodonts. Proceedings of the Estonian Academy of Sciences, Geology, 42, 23–27.
Jeppsson, L. 1998. Silurian oceanic events: summary of general characteristics. In Silurian Cycles: Linkages of Dynamic Stratigraphy with Atmospheric, Oceanic and Tectonic Changes (Landing, E. & Johnson, M. E., eds), New York State Museum Bulletin, 491, 239–257.
Jeppsson, L. 2005. A revision of the Early Wenlock stratigraphy of Gotland. Sveriges Geologiska Undersökning Rapport, 2005(7), 20–21.
Jeppsson, L. 2008. The Lower Wenlock Hangvar Formation – a sequence previously split between the Högklint and Slite beds (Silurian, Gotland, Sweden). GFF, 130, 31–40.
http://dx.doi.org/10.1080/11035890801301031
Jeppsson, L. & Aldridge, R. J. 2000. Ludlow (late Silurian) oceanic episodes and events. Journal of the Geological Society, London, 157, 1137–1148.
http://dx.doi.org/10.1144/jgs.157.6.1137
Jeppsson, L., Viira, V. & Männik, P. 1994. Silurian conodont-based correlations between Gotland (Sweden) and Saaremaa (Estonia). Geological Magazine, 131, 201–218.
http://dx.doi.org/10.1017/S0016756800010736
Jeppsson, L., Eriksson, M. E. & Calner, M. 2006. A latest Llandovery to latest Ludlow high-resolution biostratigraphy based on the Silurian of Gotland – a summary. GFF, 128, 109–114.
http://dx.doi.org/10.1080/11035890601282109
Lindström, G. 1895. On remains of a Cyathaspis from the Silurian strata of Gotland. Bihang till Kongliga Svenska Vetenskapsakademiens Handlingar, 21(4), 1–15.
Martinsson, A. 1966. Beyrichiacean ostracodes asociated with the earliest Silurian vertebrates from Gotland. GFF, 88, 327–339.
http://dx.doi.org/10.1080/11035896609448929
Martinsson, A. 1967. The succession and correlation of ostracode faunas in the Silurian of Gotland. GFF, 89, 350–386.
http://dx.doi.org/10.1080/11035896709448375
Märss, T. 1992. Vertebrate history in the Late Silurian. Proceedings of the Estonian Academy of Sciences, Geology, 41, 205–214.
Märss, T. 1996. Loganellia (Thelodonti, Agnatha) from the Jaagarahu Stage, Wenlock, Estonia. Proceedings of the Estonian Academy of Sciences, Geology, 45, 189–202.
Märss, T. 2001. Andreolepis (Actinopterygii) in the Upper Silurian of northern Eurasia. Proceedings of the Estonian Academy of Sciences, Geology, 50, 174–189.
Märss, T., Caldwell, M., Gagnier, P.-Y., Goujet, D., Männik, P., Martma, T. & Wilson, M. 1998. Distribution of Silurian and Lower Devonian vertebrate microremains and conodonts in the Baillie-Hamilton and Cornwallis Island sections, Canadian Arctic. Proceedings of the Estonian Academy of Sciences, Geology, 47, 51–76.
Nilsson, E. K. 2005. Extinctions and faunal turnovers of early vertebrates during the Late Silurian Lau Event, Gotland, Sweden. Examensarbete I Geologi vid Lunds universitet – Berggrundsgeologi, nr. 188. Geologiska institutionens Centrum för GeoBiosfärsvetenskap Lunds universitet [Dissertations in Geology at Lund University, 188].
Ørvig, T. 1979. Agnathan vertebrates. In Lower Wenlock Faunal and Floral Dynamics – Vattenfallet Section Gotland (Jaanusson, V., Laufeld, S. & Skoglund, R., eds), Sveriges Geologiska Undersökning, C 762, 249–250.
Rohon, V. 1893. Die obersilurischen Fishe von Oesel. II. Teil. Mémoires de L’Académie Imperiale des Sciences de St. Pétersbourg, Tome, 41(5), 1–113.
Samtleben, C., Munnecke, A., Bickert, T. & Pätzold, J. 1996. The Silurian of Gotland (Sweden): facies interpretation based on stable isotopes in brachiopod shells. Geologische Rundschau, 85, 278–292.
http://dx.doi.org/10.1007/BF02422234
Samtleben, C., Munnecke, A. & Bickert, T. 2000. Development of facies and C/O-isotopes in transects through the Ludlow of Gotland: evidence for global and local influences on a shallow-marine environment. Facies, 43, 1–38.
http://dx.doi.org/10.1007/BF02536983
Spjeldnaes, N. 1950. On some vertebrate fossils from Gotland with some comments on the stratigraphy. Arkiv för Mineralogi och Geologi, 1(8), 211–218.
Von Volborth, A. 1861. Vorkommen von Conodonten in England und Schweden. Neues Jahrbuch für Mineralogie und Geologie, 2, 464–465.
