Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-28T20:19:16.227Z Has data issue: false hasContentIssue false
  • English
  • Français

Biodiversity of the Silurian osteostracans of the East Baltic

Published online by Cambridge University Press:  23 February 2015

T. Märss ,
O. Afanassieva  and
H. Blom
T. Märss
Affiliation:
Institute of Geology at Tallinn University of Technology, Ehitajate Road 5, 19086 Tallinn, Estonia. Email: Tiiu.Marss@ttu.ee
O. Afanassieva
Affiliation:
Borissiak Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya 123, Moscow 117997, Russia. Email: oafan@paleo.ru
H. Blom*
Affiliation:
Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden. Email: Henning.Blom@ebc.uu.se
*
*corresponding author
Get access Rights & Permissions [Opens in a new window]

Abstract

The sculpture and histology of osteostracan head shields and trunk squamations from the Silurian of Estonia are described, illustrated and used for the identification of disarticulated microremains collected from outcrop sections and numerous drill cores in Estonia and Latvia over the last 40 years. The scattered osteostracan material contains thousands of specimens of scales and shield fragments. The sculpture and histology of species of the previously identified eight genera in the region (Tremataspis, Dartmuthia, Saaremaaspis, Oeselaspis, Aestiaspis, Thyestes, Procephalaspis, Witaaspis) are redescribed, together with Ateleaspis, found in Estonia for the first time. The sculpture on the cornua of several taxa is described for the first time. The new taxa Tremataspis perforata sp. nov., Dartmuthia procera sp. nov., Eldaaspis miklii gen. et sp. nov., Tahulaspis ordinata gen. et sp. nov., Tahulaspis praevia gen. et sp. nov., Meelaidaspis gennadii gen. et sp. nov. and Ohesaareaspis ponticulata gen. et sp. nov. are established, based upon sculpture and histological characteristics of the exoskeleton. The supraoral field with denticles of that field are described for the first time in Oeselaspis pustulata, as is the supraoral plate with buccal denticles in Meelaidaspis gennadii gen. et sp. nov. Thin sections of all taxa (except of Witaaspis) have been studied. This work sheds light on East Baltic osteostracan biodiversity from the Maasi Beds of the Jaagarahu Stage, Sheinwoodian, lower Wenlock up to the Ohesaare Stage, upper Přidoli, Silurian.

Keywords

“Agnatha”EstoniaexoskeletonsLatviamicroremainsOsteostraci
Type
Articles
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 105 , Issue 2 , June 2014 , pp. 73 - 148
Copyright
Copyright © The Royal Society of Edinburgh 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

11. References

Adrain, J. M. & Wilson, M. V. H. 1994. Early Devonian cephalaspids (Vertebrata: Osteostraci: Cornuta) from the southern Mackenzie Mountains, N.W.T., Canada. Journal of Vertebrate Paleontology 14, 301–19.Google Scholar
Afanassieva, O. B. 1985. Peculiarities of the exoskeleton of thyestids (Agnatha). Paleontologicheskii Zhurnal no. 4, 70–75. [In Russian.]Google Scholar
Afanassieva, O. B. 1986. The structure of the exoskeleton of cephalaspids from the Silurian of Estonia. Paleontological Journal 20, 67–74.Google Scholar
Afanassieva, O. B. 1991. The Osteostracans of the USSR (Agnatha). Trudy Paleontologicheskogo Instituta SSSR 248. Moscow: Nauka. 144 pp. [In Russian with English summary.]Google Scholar
Afanassieva, O. B. 1995. The structure of the exoskeleton of Tremataspidoidei and its significance in the taxonomy of Osteostracans (Agnatha). Geobios, Mémoire Spécial 19, 13–18.Google Scholar
Afanassieva, O. B. 1996. On the morphology and systematic position of the tremataspid osteostracan Aestiaspis viitaensis (Agnatha). Paleontological Journal 30, 566–70.Google Scholar
Afanassieva, O. B. 2000. New osteostracans from the Silurian of Severnaya Zemlya Archipelago (Russia) and some problems relating to the parataxonomy of armoured agnathans. Paleontological Journal 34, suppl. 2, S138–S146.Google Scholar
Afanassieva, O. B. 2002. The exoskeleton of Thyestes verrucosus (Osteostraci, Agnatha) from the Silurian of Saaremaa Island: a mode of ossification. In Satkūnas, J. & Lazauskienė, J. (eds) The Fifth Baltic Stratigraphical Conference: Basin stratigraphy – modern methods and problems. September 22–27, 2002. Extended Abstracts, 9–10. Vilnius: Geological Survey of Lithuania.Google Scholar
Afanassieva, O. B. 2004. Subclass Osteostraci. Osteostracans. In Novitskaya, L. I. & Afanassieva, O. B. (eds) Fossil vertebrates of Russia and adjacent countries. Agnathans and early fishes, 210–67. Moscow: GEOS. 436 pp. [In Russian with English summary on pp 420–421.]Google Scholar
Afanassieva, O. B. 2011. On the morphology and taxonomic position of Ungulaspis arctoa (Osteostraci, Agnatha) from the Lower Devonian of the Severnaya Zemlya Archipelago. Paleontological Journal 45, 567–571.Google Scholar
Afanassieva, O. B. 2014. Development of the exoskeleton in osteostracans (Agnatha, Vertebrata): new evidence of growth. Paleontological Journal 48, suppl., no. 9, 973–79.Google Scholar
Afanassieva, O. B. & Karatajūtė-Talimaa, V. N. 1998. New osteostracans (Agnatha) from the Silurian and Lower Devonian of the Severnaya Zemlya Archipelago (Russia). Paleontological Journal 32, 60–64.Google Scholar
Afanassieva, O. B. & Karatajūtė-Talimaa, V. N. 2009. The histology of the Upper Silurian osteostracan Timanaspis kossovoii Obruchev (Agnatha) from North Timan, Russia. Acta Zoologica (Stockholm) 90, Suppl. 1, 38–43.Google Scholar
Afanassieva, O. B. & Karatajūtė-Talimaa, V. N. 2013. New data on osteostracans (Agnatha) from the Lower Devonian of the Severnaya Zemlya Archipelago. Paleontological Journal 47, 513–22.Google Scholar
Afanassieva, O. B. & Märss, T. 1997. Exoskeleton structure and the distribution of Aestiaspis viitaensis (Agnatha) from the Silurian of Estonia. Paleontological Journal 31, 641–47.Google Scholar
Afanassieva, O. B. & Märss, T. 2014. New data on the exoskeleton of the osteostracan genus Aestiaspis (Agnatha) from the Silurian of Saaremaa Island (Estonia) and the Severnaya Zemlya Archipelago (Russia). Paleontological Journal 48, 74–78.Google Scholar
Berg, L. S. 1937. A classification of fish-like vertebrates. Bulletin de'l Académie des Sciences de l'URSS. Classe des sciences mathématiques et naturelles 1937, 1277–80. [In English and Russian.]Google Scholar
Berg, L. S. 1940. System of the fish-like and fishes, recent and fossil. Investigations of the Institute of Zoology Academy of Sciences USSR 5, 87–517. [In Russian.]Google Scholar
Blieck, A., Goujet, D. & Janvier, P. 1987. The vertebrate stratigraphy of the Lower Devonian (Red Bay Group and Wood Bay Formation) of Spitsbergen. Modern Geology 11, 197–217.Google Scholar
Blieck, A. & Heintz, N. 1979. The heterostracan faunas in the Red Bay Group (Lower Devonian) of Spitsbergen and their biostratigraphical significance: a review including new data. Bulletin de la Société Géologique du France, 7e Série 21, 169–81.Google Scholar
Blom, H., Märss, T. & Miller, G. C. 2002. Silurian and earliest Devonian birkeniid anaspids from the Northern Hemisphere. Transactions of the Royal Society of Edinburgh: Earth Science 92(for 2001), 263–323.Google Scholar
Blom, H. & Goujet, D. 2002. Thelodont scales from the Devonian Red Bay Group, Spitsbergen. Palaeontology 45, 795–820.Google Scholar
Bölau, E. 1949. Über die Verbreitung der Ostrakodermen in der Kaarma Stufe (K1) von Saaremaa (Ösel). Apophoreta Tartuensis. Societatis Litterarum Estonicae in Svecia. Stockholm 1949, 428–33.Google Scholar
Bölau, E. 1951. Das Sinnesliniensystem der Tremataspiden und dessen Beziehungen zu anderen Gefäss-Systemen des Exoskeletts. Acta Zoologica 32, 31–40.Google Scholar
Bölau, E. 1957. Über die Bildung von sekundären symmetrischen Grubensystemen auf dem Dorsal- und Ventralschield von Tremataspis mammillata. Annales Societatis Tartuensis ad Res Naturae Investigandas Constitutae. Series nova in exsilio condita, Lund 1, 135–47.Google Scholar
Davies, N. S., Turner, P. & Sansom, I. J. 2005. A revised stratigraphy for the Ringerike Group (Upper Silurian, Oslo Region). Norwegian Journal of Geology 85, 193–201.Google Scholar
Denison, R. H. 1947. The exoskeleton of Tremataspis. American Journal of Science 245, 337–65.Google Scholar
Denison, R. H. 1951a. Evolution and classification of the Osteostraci. Fieldiana: Geology 11, 155–96.Google Scholar
Denison, R. H. 1951b. The exoskeleton of the early Osteostraci. Fieldiana: Geology 11, 197–218.Google Scholar
Denison, R. H. 1952. Types and figured specimens of fossil fishes in the Patten collection, Dartmouth College Museum, Hanover, New Hampshire. American Midland Naturalist 48, 161–64.Google Scholar
Denison, R. H. 1956. Review of the habitat of the earliest vertebrates. Fieldiana: Geology 11, 357–457.Google Scholar
Denison, R. H. 1963. The early history of the vertebrate calcified skeleton. Clinical Orthopaedics 31, 141–52.Google Scholar
Dineley, D. L. & Loeffler, E. J. 1976. Ostracoderm Faunas of the Delorme and associated Siluro-Devonian Formations, North West Territories, Canada. Special Papers in Palaeontology 18, 1–214.Google Scholar
Eichwald, E. von. 1854. Die Grauwackenschichten von Liv- und Esthland. Bulletin de la Société Imperiale des Naturalists de Moscou 27, 1–111.Google Scholar
Fredholm, D. 1988. Vertebrate biostratigraphy of the Ludlovian Hemse Beds of Gotland, Sweden. Geologiska Föreningens i Stockholm Förhandlingar 110, 237–53.Google Scholar
Fredholm, D. 1990. Agnathan vertebrates in the Lower Silurian of Gotland, Sweden. Geologiska Föreningens i Stockholm Förhandlingar 112, 61–84.Google Scholar
Gross, W. 1935. Histologische Studien am Aussenskelett fossiler Agnathen und Fische. Palaeontographica Abteilung A 83, 1–60.Google Scholar
Gross, W. 1947. Die Agnathen und Acanthodier der Obersilurischen Beyrichienkalks. Palaeontographica Abteilung A 96, 91–161.Google Scholar
Gross, W. 1956. Über Crossopterygier und Dipnoer aus dem baltischen Oberdevon im Zusammenhang einer vergleichenden Untersuchung des Porenkanalsystems paläozoischer Agnather und Fische. Kungliga Svenska vetenskapsakademiens handlingar 5, 3–140.Google Scholar
Gross, W. 1961. Aufbau des Panzers obersilurischer Heterostraci und Osteostraci Norddeutschlands (Geschiebe) und Oesels. Acta Zoologica 42, 73–150.Google Scholar
Gross, W. 1968a. Die Agnathen-Fauna der silurischen Halla-Schichten Gotlands. Geologiska Föreningens i Stockholm Förhandlingar 90, 369–400.Google Scholar
Gross, W. 1968b. Beobachtungen mit dem Elektronenraster-Auflichtmicroskop an den Siebplatten und dem Isopedin von Dartmuthia (Osteostraci). Paläontologische Zeitschrift 42, 73–82.Google Scholar
Heintz, A. 1967. A new tremataspidid from Ringerike, South Norway. Journal of the Linnean Society of London, Zoology 47, 55–68.Google Scholar
Heintz, A. 1969. New agnathans from Ringerike Sandstone. Skrifter utgitt av Det Norske Videnskaps-Akademi I Oslo (Matematisk naturvidenskapelig klasse) 26, 1–28.Google Scholar
Janvier, P. 1974. The sensory-line system and its innervation in the Osteostraci (Agnatha, Cephalaspidomorphi). Zoologica Scripta 3, 91–99.Google Scholar
Janvier, P. 1975. Spécialisations précoces et caractères primitifs du système circulatoire des Osteostracés. Colloques internals du C.N.R.S. 218, 15–30.Google Scholar
Janvier, P. 1978. Les nageoires paires des Osteostracés et la position systématique des Céphalaspidomorphes. Annales de Paléontologie 64, 113–42.Google Scholar
Janvier, P. 1981. Norselaspis glacialis n. g., n. sp. et les relations phylogénétiques entre les kiaeraspidiens (Osteostraci) du Dévonien inférieur du Spitsbergen. Palaeovertebrata 11, 19–131.Google Scholar
Janvier, P. 1985a. Les thyestidiens (Osteostraci) du Silurien de Saaremaa (Estonie). Première partie: morphologie et anatomie. Annales de Paléontologie 71, 83–147.Google Scholar
Janvier, P. 1985b. Les thyestidiens (Osteostraci) du Silurien de Saaremaa (Estonie). Deuxième partie: analyse phylogénétique, répartition stratigraphique, remarques sur les genres Auchenaspis, Timanaspis, Tyriaspis, Didymaspis, Sclerodus et Tannuaspis. Annales de Paléontologie 71, 187–216.Google Scholar
Janvier, P. 1996. Early Vertebrates. Oxford Monographs on Geology and Geophysics. Oxford: Clarendon Press. 393 pp.Google Scholar
Janvier, P. & Lelièvre, H. 1994. A new tremataspid osteostracan, Aestiaspis viitaensis n. g., n. sp., from the Silurian of Saaremaa, Estonia. Proceedings of the Estonian Academy of Sciences. Geology 43, 122–28.Google Scholar
Kaljo, D. & Märss, T. 1991. Pattern of some Silurian bioevents. Historical Biology 5, 145–52.Google Scholar
Kiaer, J. 1911. A new Downtonian fauna in the Sandstone Series of the Kristiania area. Skrifter utgitt av Det Norske Videnskaps-Akademi i Oslo I, 1–22.Google Scholar
Lankester, E. R. 1868–1870. A monograph of the fishes of the Old Red Sandstone of Britain. 1. Cephalaspidae. Palaeontographical Society London, 1–62.Google Scholar
Luha, A. 1940. Uusi ostrakoderme Saaremaa Eurypterus-lademest. Eesti Loodus 1, 17–24.Google Scholar
Mark-Kurik, E. & Noppel, T. 1970. Additional notes on the distribution of vertebrates in the Silurian of Estonia. ENSV TA Toimetised Keemia. Geoloogia 19, 171–73.Google Scholar
Märss, T. 1982. Vanimate selgroogsete leiud Saaremaal. Eesti Loodus 10, 646–54. [In Estonian with English summary.]Google Scholar
Märss, T. 1983. Silurian vertebrates of Estonia and West Latvia. Unpublished candidate degree Thesis in the geological–mineralogical sciences. Tallinn: Institute of Geology, Academy of Sciences of the Estonian SSR. [In Russian.]Google Scholar
Märss, T. 1986. Silurian vertebrates of Estonia and West Latvia. Fossilia Baltica 1. Tallinn: Valgus. 104 pp. [In Russian with English summary.]Google Scholar
Märss, T. 1990a. Viita trench. In Kaljo, D. & Nestor, H. (eds) Field Meeting, Estonia 1990. An Excursion Guidebook, 168–69. Tallinn.Google Scholar
Märss, T. 1990b. Himmiste Quarry. In Kaljo, D. & Nestor, H. (eds) Field Meeting, Estonia 1990. An Excursion Guidebook, 169–70. Tallinn.Google Scholar
Märss, T. 1991. Agnathans and fishes in shallow facies of the Northeast Baltic Wenlock and Ludlow. Proceedings of the Estonian Academy of Sciences. Geology 40, 89–95. [In Russian with English summary.]Google Scholar
Märss, T. 1992. Vertebrate history in the Late Silurian. Proceedings of the Estonian Academy of Sciences. Geology 41, 205–14.Google Scholar
Märss, T., Perens, H. & Klaos, T. 2003. Sedimentation of the Himmiste-Kuigu fish bed (Ludlow of Estonia), and taphonomy of the Phlebolepis elegans Pander (Thelodonti) shoal. Proceedings of the Estonian Academy of Sciences. Geology 52, 239–64.Google Scholar
Märss, T. & Einasto, R. 1978. Distribution of vertebrates in deposits of various facies in the North Baltic Silurian. ENSV TA Toimetused Keemia. Geoloogia 27, 16–22. [In Russian with English summary.]Google Scholar
Märss, T. & Männik, P. 2013. Revision of Silurian vertebrate biozones and their correlation with the conodont succession. Estonian Journal of Earth Sciences 62, 181–204.Google Scholar
Märss, T. & Ritchie, A. 1998. Articulated thelodonts (Agnatha) of Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 88(for 1997), 143–95.Google Scholar
Modzalevskaya, T. & Märss, T. 1991. On the age of the lower boundary of the Greben Regional Stage of the Urals. Proceedings of the Estonian Academy of Sciences. Geology, 40, 100–03. [In Russian with English summary.]Google Scholar
Nestor, H. 1990a. Some aspects of lithology of the Ordovician and Silurian rocks. In Kaljo, D. & Nestor, H. (eds) Field Meeting. Estonia 1990. An Excursion Guidebook, 27–32. Tallinn.Google Scholar
Nestor, H. 1990b. Basin development and facies models. In Kaljo, D. & Nestor, H. (eds) Field Meeting, Estonia 1990. An Excursion Guidebook, 33–36. Tallinn.Google Scholar
Nestor, H. 1997. Silurian. In Raukas, A. & Teedumäe, A. (eds) Geology and Mineral resources of Estonia, 89–106. Tallinn: Estonian Academy Publishers.Google Scholar
Nestor, H. & Einasto, R. 1977. Facies-sedimentary model of the Silurian Paleobaltic pericontinental basin. In Kaljo, D. (ed.) Facies and Fauna of the Baltic Silurian, 89–121. Tallinn: Valgus. [In Russian with Estonian and English summaries.]Google Scholar
Nestor, H. & Einasto, R. 1997. Ordovician and Silurian carbonate sedimentation basin. In Raukas, A. & Teedumäe, A. (eds) Geology and mineral resources of Estonia, 192–204. Tallinn: Estonian Academy Publishers.Google Scholar
Obruchev, D. V. 1964. Agnathans and fishes. In Orlov, Y. O. (ed.) Fundamentals of Paleontology 11, 1–522. Moscow: Nauka.Google Scholar
Obruchev, D. V. 1973. The importance of vertebrates for the correlations of the Silurian and Lower-Middle Devonian sediments of the USSR. In Menner, V. (ed.) Stratigraphy of the Lower and Middle Devonian. Contributions to the III International Symposium on the Silurian-Devonian boundary and stratigraphy of the Lower and Middle Devonian (Leningrad 1968) Vol. 2, 189–97. Leningrad: Nauka. [In Russian with English summary.]Google Scholar
Ørvig, T. 1951. Histologic studies of placoderms and fossil elasmobranchs. I. The endoskeleton, with remarks on the hard tissues of lower vertebrates in general. Arkiv för Zoologi 2, 321–454.Google Scholar
Ørvig, T. 1957. Remarks on the vertebrate fauna of the Lower Upper Devonian of Escuminac Bay, P. Q. Canada, with special reference to the porolepiform crossopterygians. Arkiv för Zoologi 10, 367–426.Google Scholar
Pander, Ch. 1856. Monographie der fossilen Fische der silurischen Systems der Russisch-Baltischen Gouvernements. Obersilurische Fische. Kaiserlichen Akademie des Wissenschaften, 37–91.Google Scholar
Patten, W. 1903a. On the appendages of Tremataspis. American Naturalist 37, 223–42.Google Scholar
Patten, W. 1903b. On the structure and classification of the Tremataspidae. Mémoires de l'Académie Impériale des Sciences de St. Pétersbourg. Classe Physico-mathématique 13, 1–33.Google Scholar
Patten, W. 1931a. New ostracoderms from Oesel. Science 73, 671–73.Google Scholar
Patten, W. 1931b. The Dartmouth Expedition to the Island of Oesel. The Dartmouth Alumni Magazine, 1–5.Google Scholar
Perens, R., Perens, H. & Lelgus, M. 1994. Report on the complex geological mapping (1:50000) of Saaremaa Island (vol. 1). Keila: Geological Survey of Estonia.Google Scholar
Põldvere, A. (compiler). 2003. Ruhnu (500) drill core. In Estonian geological sections. Bulletin 5. Tallinn: Geological Survey of Estonia. 76 pp.Google Scholar
Ritchie, A. 1967. Ateleaspis tessellata Traquair, a non-cornuate cephalaspid from the Upper Silurian of Scotland. Zoological Journal of the Linnean Society, London 47, 69–81.Google Scholar
Ritchie, A. 1980. The Late Silurian anaspid genus Rhyncholepis from Oesel, Estonia, and Ringerike, Norway. American Museum Novitates 2699, 1–18.Google Scholar
Robertson, G. 1989. A palaeoenvironmental interpretation of the Silurian rocks in the Pentland Hills, near Edinburgh, Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 80, 127–41.Google Scholar
Robertson, G. M. 1935a. Oeselaspis, a new genus of ostracoderm. American Journal of Science 29, 453–61.Google Scholar
Robertson, G. M. 1935b. The ostracoderm genus Dartmuthia Patten. American Journal of Science 29, 323–35.Google Scholar
Robertson, G. M. 1935c. The ostracoderm order Osteostraci. Science 82, 282–83.Google Scholar
Robertson, G. M. 1937. Anaspida from the Ludlow of Oesel. Journal of Paleontology 11, 256.Google Scholar
Robertson, G. M. 1938a. The Tremataspididae. American Journal of Science 35, no. 207, Part I, 172–206; no. 208, Part II, 273–96.Google Scholar
Robertson, G. M. 1938b. New genera of ostracoderms from the Upper Silurian of Oesel. Journal of Paleontology 12, 486–93.Google Scholar
Robertson, G. M. 1939a. An Upper Silurian vertebrate horizon with description of a new species, Cephalaspis oeselensis. Transactions of the Kansas Academy of Science 42, 357–63.Google Scholar
Robertson, G. M. 1939b. The status of Cephalaspis schrenkii Pander from the Upper Silurian of Oesel. Journal of Geology 47, 649–57.Google Scholar
Robertson, G. M. 1940a. Witaaspis patteni, a new ostracoderm from the Upper Silurian of Oesel. Transactions of the Kansas Academy of Science 43, 297–98.Google Scholar
Robertson, G. M. 1940b. The sensory canal system in some early vertebrates. Transactions of the Kansas Academy of Science 43, 467–71.Google Scholar
Robertson, G. M. 1941. The ostracoderm order Anaspida, with description of some Upper Silurian material. Transactions of the Kansas Academy of Science 44, 314–17.Google Scholar
Robertson, G. M. 1945. Cephalaspids from the Upper Silurian of Oesel [Estonia], with a discussion of cephalaspid genera. American Journal of Science 243, 169–91.Google Scholar
Robertson, G. M. 1947. Proposed suspension of the Règles for Tremataspis Schmidt, 1866 (Class Cephalaspidomorphi, order Osteostraci). Bulletin of Zoological Nomenclature I, pt. 10, 237–38.Google Scholar
Robertson, G. M. 1949. Some contributions of fossil study to the problem of vertebrate origin. Proceedings of the Iowa Academy of Science 56, 379–84.Google Scholar
Robertson, G. M. 1950. Species criteria in Osteostraci, with special reference to the genus Tremataspis. American Journal of Science 248, 335–46.Google Scholar
Robertson, G. M. 1954. The nature of the so-called electric organs in ostracoderms. Proceedings of the Iowa Academy of Science 61, 598–602.Google Scholar
Robertson, G. M. 1955. Problems of origin and early development of vertebrates: skeletal tissues. Proceedings of the Iowa Academy of Science 62, 493–97.Google Scholar
Robertson, G. M. 1957. Agnatha. Geological Society of America, Memoir 67, 995–98.Google Scholar
Robertson, G. M. 1970. The oral region of ostracoderms and placoderms, possible phylogenetic significance. American Journal of Science 269, 39–64.Google Scholar
Rohon, J. V. 1892. Die obersilurischen Fische von Oesel. I Theil. Thyestidae und Tremataspidae. Mémoires de L'Académie Impériale des Sciences de St.-Pétersbourg 38, 1–88. St. Petersburg.Google Scholar
Rohon, J. V. 1893. Die obersilurischen Fische von Oesel. II Theil. Selachii, Dipnoi, Ganoidei, Pteraspidae und Cephalaspidae. Mémoires de L'Académie Impériale des Sciences de St.-Pétersbourg 41, 1–124. St. Petersburg.Google Scholar
Rohon, J. V. 1894. Zur Kenntnis der Tremataspiden. (Nachtrag zu den Untersuchungen über “Die obersilurischen Fische von Oesel”). Bulletin de l'Académie Impériale des Sciences de St.-Pétersbourg, Nouvelle Série 4, 201–25.Google Scholar
Rohon, J. V. 1895. Die Segmentierung am Primordialcranium der obersilurischen Thyestiden. Die Segmentirung [sic!] am Primordial Cranium der obersilurischen Thyestiden. Verhandlungen der russisch-kaiserlichen mineralogischen Gesellschaft zu St. Petersburg 2 ser. 33, 17–64.Google Scholar
Rohon, J. V. 1896. Weitere Mittheilungen über die Gattung Thyestes. Bulletin de l'Académie Impériale des Sciences de St.-Pétersbourg 5 ser. 4, 223–35. St. Petersburg.Google Scholar
Rolfe, W. D. I. 1992. Excursion 21. Hagshaw Hills. In Lawson, J. D. & Weedon, D. S. (eds) Geological excursions around Glasgow and Girvan, 265–79. Glasgow: The Geological Society of Glasgow.Google Scholar
Rõõmusoks, A. 1983. Eesti aluspõhja geoloogia. Tallinn: Valgus. 224 pp.Google Scholar
Sansom, R. 2008. The origin and early evolution of the Osteostraci (Vertebrata): A phylogeny for the Thyestiida. Journal of Systematic Palaeontology 6, 317–32.Google Scholar
Sansom, R. 2009. Phylogeny, classification and character polarity of the Osteostraci (Vertebrata). Journal of Systematic Palaeontology 7, 95–115.Google Scholar
Schmidt, F. 1866. Ueber Thyestes verrucosus Eichwald und Cephalaspis schrenkii Pander, nebst einer Einleitung über das vorkommen silurischen Fischreste auf der Insel Oesel. Verhandlungen der kaiserlichen russischen mineralogischen Gesellschaft, St. Petersbourg 2, 217–50.Google Scholar
Schmidt, F. 1894. Ueber Cephalaspis (Thyestes) schrenkii Pander aus dem Obersilur von Rotziküll auf Oesel. Bulletin de l'Académie Impériale des Sciences de St. Pétersbourg (Mélanges géologiques et paléontologiques) 4, 383–90.Google Scholar
Schultze, H.-P. 2009. The international influence of the Stockholm School. Acta Zoologica (Stockholm) 90, suppl. 1, 22–37.Google Scholar
Stensiö, E. A. 1927. The Downtonian and Devonian vertebrates of Spitsbergen. 1. Family Cephalaspidae. Skrifter om Svalbard og Ishavet 12, 1–391.Google Scholar
Stensiö, E. A. 1932. The cephalaspids of Great Britain. London: British Museum (Natural History). 220 pp.Google Scholar
Stensiö, E. A. 1958. Les Cyclostomes fossiles ou ostracodermes. In Grassé, P.-P. (ed.) Traité de Zoologie 13, 173–425. Paris: Masson.Google Scholar
Tarlo, L. B. H. 1967. Agnatha. In Harland, W. B., Holland, C. H., House, M. R., Hughes, N. F., Reynolds, A. B., Rudwick, M. J. S., Satterthwaite, G. E., Tarlo, L. B. H. & Willey, E. C. (eds) The Fossil Record. Geological Society, London, Special Publications 2, 629–36.Google Scholar
Traquair, R. H. 1899. Report on Fossil Fishes collected by the Geological Survey of Scotland in the Silurian Rocks of the South of Scotland. Transactions of the Royal Society of Edinburgh 39, 827–64.Google Scholar
Vergoossen, J. M. J. 1999a. Late Silurian fish microfossils from an East Baltic derived erratic from Oosterhaule, with a description of new acanthodian taxa. Geologie en Mijnbouw 78, 231–51.Google Scholar
Vergoossen, J. M. J. 1999b. Late Silurian fish microfossils from Helvetesgraven, Skåne (southern Sweden). Geologie en Mijnbouw 78, 267–80.Google Scholar
Vergoossen, J. M. J. 2002a. Late Silurian fish microfossils from Ramsåsa, locality H, Scania, south Sweden, with some remarks on the body zonation scheme used in thelodont studies. Scripta Geologica 123, 41–69.Google Scholar
Vergoossen, J. M. J. 2002b. Late Silurian fish microfossils from Klinta and Rinnebäcks Bro (Scania, south Sweden), with remarks on the morphology of Nostolepis striata trunk scales. Scripta Geologica 123, 71–92.Google Scholar
Vergoossen, J. M. J. 2003. First record of fish microfossils from Ramsåsa, site C, Skåne, southern Sweden. Scripta Geologica 126, 1–78.Google Scholar
Vergoossen, J. M. J. 2004. Fish microfossils from Ramsåsa, site E, Skåne, southern Sweden (mid Palaeozoic). Scripta Geologica 127, 1–70.Google Scholar
Walton, E. K. & Oliver, G. J. H. 1991. Lower Palaeozoic – stratigraphy. In Craig, G.Y. (ed.) Geology of Scotland (third edition), 161–93. Edinburgh: Scottish Academic Press.Google Scholar
Wellman, C. H. & Richardson, J. B. 1993. Terrestrial plant microfossils from Silurian Inliers of the Midland Valley of Scotland. Palaeontology 36, 155–93.Google Scholar
Wängsjö, G. 1944. On the genus Dartmuthia Patten, with special reference to the minute structure of the exoskeleton. Bulletin of the Geological Institute of Uppsala 31, 349–62.Google Scholar
Wängsjö, G. 1952. The Downtonian and Devonian vertebrates of Spitsbergen. IX. Morphologic and systematic studies of the Spitsbergen Cephalaspids. Skrifter Norsk Polarinstitutt 97, 1–657.Google Scholar
Woodward, A. S. 1891. Catalogue of the fossil fishes in the British Museum (Natural History) 2. 576 pp. London: British Museum.Google Scholar
Worsley, D., Aarhus, N., Bassett, M. G., Howe, M. P. A., Mørk, A. & Olaussen, S. 1983. The Silurian succession of the Oslo Region. Norges Geologiske Undersøkelse 384, 1–57.Google Scholar