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Paläontologische Zeitschrift

, Volume 70, Issue 1–2, pp 171–180 | Cite as

A new early cyclostome bryozoan from the Lower Ordovician (Volkhov Stage) of Russia

  • Paul D. Taylor
  • Sergei Rozhnov
Article

Abstract

Goryunovia hemiseptata n.gen. n.sp. is an unusual Lower Ordovician cyclostome bryozoan, represented by a single colony from the Middle Volkhov Stage (Arenig) of the Leningrad Oblast. The encrusting uniserial colony consists of large, slender zooids, many with closely-spaced partial diaphragms (hemisepta), and has a distinctive trichotomous branching pattern. Skeletal organization is of the sagenellid grade: calcified interior walls appear to be present, and the exterior frontal walls lack pseudopores. As details of microstructure and early astogeny are unknown, it is difficult to interpret the phylogenetic relationships ofGoryunovia until further material is forthcoming. However, there is some resemblance with the enigmatic hederellids, which appear in the Upper Silurian and possibly range into the Triassic.

Keywords

Devonian Ordovician Frontal Wall Leningrad Oblast Clayey Limestone 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Kurzfassung

Goryunovia hemiseptata n.gen. n.sp. ist eine außergewöhnliche cyclostome Bryozoe aus der mittleren Volkov-Stufe (Arenig) des Leningrader Oblast, von welcher bis jetzt nur eine einzige Kolonie bekannt ist. Die inkrustierende uniserielle Kolonie besteht aus langen, schmalen Zooiden, von denen viele dicht gepackte Trennwände (Hemisepta) aufweisen und zeigt ein typisches trichotomes Verzweigungsmuster. Die Organisation des Skelettes ist vergleichbar mit derjenigen der Sagenellidae: Es scheinen kalzifizierte Innenwände vorhanden zu sein; die Pseudoporen der externen Frontalwände fehlen. Da weder Details der Mikrostruktur, noch die Astogenese bekannt sind, ist eine Interpretation der phylogenetischen Verwandtschaftsbeziehungen solange schwierig zu beurteilen, bis neues Material vorhanden ist. Es bestehen Ähnlichkeiten mit den rätselhaften Hederelliden, welche im Silur auftreten und möglicherweise bis in die Trias hineinreichen.

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References

  1. Bassler, R. S. 1911.Corynotrypa, a new genus of tubuliporoid Bryozoa. - Proceedings of the United States National Museum39: 497–527, Washington.Google Scholar
  2. — 1939. The Hederelloidea, a suborder of Paleozoic cyclostomatous Bryozoa. - Proceedings of the United States National Museum87: 25–91, Washington.Google Scholar
  3. Bizzarini, F. &Braga, G. 1994.Corynotrypoides ladina gen. et sp. nov, a questionable cyclostomatous bryozoan from the Upper Triassic of the Eastern Dolomites (NE Italy). - [In:]Hayward, P. J.; Ryland, J. S. &Taylor, P. D. (eds.) Biology and palaeobiology of bryozoans: 29–32, Fredensborg.Google Scholar
  4. Brood, K. 1973. Palaeozoic Cyclostomata (a preliminary report). - [In:]Larwood, G. P. (ed.) Living and fossil Bryozoa: 247–256, London.Google Scholar
  5. — 1975. Cyclostomatous Bryozoa from the Silurian of Gotland. - Stockholm Contributions in Geology28: 45–119, Stockholm.Google Scholar
  6. Busk, G. 1852. An account of the Polyzoa, and sertularian Zoophytes, collected in the Voyage of the Rattlesnake, on the Coasts of Australia and the Loisiade Archipelago, & c. - [In:]MacGillivray, J. Narrative of the Voyage of H.M.S. Rattlesnake, during the years 1846–1850, 1: 343–402, London.Google Scholar
  7. Buttler, C. J. 1994. Ordovician (Ashgill) microbryozoans from the Kildare Limestone, Ireland. - [In:]Hayward, P.J.; Ryland, J.S. &Taylor, P.D. (eds.) Biology and palaeobiology of bryozoans: 37–40, Fredensborg.Google Scholar
  8. Dmitrovskaja Ju. E. 1991. Nizhniy paleozoy Moskovskoy sineklizy (fauna, stratigrafija, paleogeografija). [Lower Paleozoic in Moscow syncline (fauna, stratigraphy, paleogeography)]. - Avtoreferat dissertacii na soiskanie uschenoi stepeni doktora geologo-mineralogischeskih nauk [Doctoral Thesis]: 1–60, Yaroslavl.Google Scholar
  9. Dzik, J. 1981. Evolutionary relationships of the early Palaeozoic ‘cyclostomatous’ Bryozoa. - Palaeontology24: 117–120, London.Google Scholar
  10. — 1994. Bryozoa of the Mójcza Limestone. - Palaeontologia Polonica53: 253–282, Warsaw.Google Scholar
  11. Kaljo, D. L. (ed.) 1987. Resheniya mezhvedomstvennogo stratigraficheskogo soveshchaniya po ordoviky i silury vostochno-evropeiskoi platformy 1984 g. c regional’nymi stratigraficheskimi skhemami. [Decisions of the Interdepartmental Stratigraphical Congress, 1984, on the Ordovician and Silurian of the Eastern European Platform with stratigraphical charts]: 1–115, Leningrad.Google Scholar
  12. Kiepura, M. 1973. Devonian bryozoans of the Holy Cross Mountains, Poland. Part II. Cyclostomata and Cystoporata. - Acta Palaeontologica Polonica18: 323–400, Warsaw.Google Scholar
  13. Lamansky, W. 1905. Drevneichie sloi siluriiskih otlozheniy Rossii. Die aeltesten silurischen Schichten Russlands (Etage B). [In Russian and in German]. - Trudy Geologischeskogo Comiteta. Novaja serija20: 1–203, St-Petersburg.Google Scholar
  14. Männil, R.M. 1966. Istoria razvitiya baltiiskogo basseina v ordovike. [Evolution of the Baltic Basin during the Ordovician]: 1–199, Tallin.Google Scholar
  15. Solle, G. 1968. Hederelloidea (Cyclostomata) und einige ctenostome Bryozoen aus dem Rheinischen Devon. - Abhandlungen des Hessischen Landesamtes für Bodenforschung54: 1–40, Wiesbaden.Google Scholar
  16. Taylor, P. D. &Curry, G. B. 1985. The earliest known fenestrate bryozoan, with a short review of Lower Ordovician Bryozoa. - Palaeontology28: 147–158, London.Google Scholar
  17. Taylor, P. D. &Larwood, G. P. 1990. Major evolutionary radiations in the Bryozoa. - [In:]Taylor, P.D. &Larwood, G. P. (eds.) Major Evolutionary Radiations: 209–233, London.Google Scholar
  18. Taylor, P. D. &Wilson, M. A. 1994.Corynotrypa from the Ordovician of North America: colony growth in a primitive stenolaemate bryozoan. - Journal of Paleontology68: 241–257, Lawrence.Google Scholar
  19. - In press. A new bryozoan genus from the Late Ordovician of North America and its bearing on the origin of the post-Palaeozoic cyclostomes. - [In:]Gordon, D. P.; Smith, A. M. &Grant-Mackie, J. A. (eds.) Bryozoans in space and time. - Wellington.Google Scholar

Copyright information

© E. Schweizerbart’sche Verlagsbuchhandlung 1996

Authors and Affiliations

  • Paul D. Taylor
    • 1
  • Sergei Rozhnov
    • 2
  1. 1.Department of PalaeontologyThe Natural History MuseumLondon
  2. 2.Palaeontological Institute of the Russian Academy of SciencesMoscowRussia

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