Vladimir Tsyganko - Fauna and eustatic changesof the Frasnian sea on the north Pechora plate

3rd session: Chondrichthyans
Gavin F. Hanke *, Mark V. H. Wilson - Structure and variation of acanthodian and chondrichthyan scales from the Lower Devonian of the Mackenzie Mountains, Canada
Mark V. H. Wilson *, Gavin F. Hanke - Body form and fin spines in species with scales of chondrichthyan growth pattern from the Lower Devonian of the Mackenzie Mountains, Canada
Valentina Karatajute -Talimaa *, Roma Mertiniene - Morphogenetic types of squamation of Devonian and Early Carboniferous chondrichthyans
Claire Derycke *, Zarela Herrera, Patrick R. Racheboeuf, Roland Trompette - Oldest Middle Palaeozoic ichthyofauna from Mauritania
Kate Trinajstic - Frasnian sharks from the Gneudna Formation, Western Australia Alexander Ivanov - Late Devonian - Early Permian chondrichthyans of Russian Arctic Michael Williams - Tooth retention in cladodont sharks
Rodrigo Soler-Gijon - Heterochrony and the evolution of the xenacanth sharks
Martha Richter - Dental histology and its bearing on the systematics of the Xenacanthiformes (Pisces: Chondrichthyes) Oliver Hampe - British Xenacanths
Andrea Tintori - New Chondrichthyan fauna from the Guadalupian (middle Permian) of the Sultanate of Oman
Gary D. Johnson - Dentitions of Late Palaeozoic Orthacanthusspecies and new species of ?Xenacanthus (Chondrichthyes: xenacanthiformes) from North America
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More than 50 participants from 16 countries (Australia, Canada, Estonia, France, Germany, Ireland, Italy, Latvia, Lithuania, Netherlands, Poland, Russia, Sweden, Ukraine, U.K., U.S.A.) attended. The main emphasis was on palaeobiological and biostratigraphic studies of both vertebrates and invertebrates in the Canadian, Russian, Danish, and Norwegian Arctic. Two workshops were held: geology of the Timan-Pechora region, and the early fossil record of Chondrichthyes. The field excursion on Sept. 6-7 visited important Devonian localities in the Holy Cross Mountains.
The meeting provided a forum for reporting of significant advances in biostratigraphical and paleobiological research. Some 41 extended abstracts were published in the conference volume: M. Ginter and M.V.H. Wilson (eds). 1998. Circum-Arctic Palaeozoic Faunas and Facies. Warszawa, Poland, 1998. Ichthyolith Issues Special Publication 4, 62 pp and a field guide (Skompski, 1998).

What has Valya found at Ostrowka Quarry? (Ginter photo)

Several participants brought manuscripts for the Severnaya Zemlya volume, which will be published, in Paris, as a special issue of Geodiversitas. These papers cover Ordovician to Devonian thelodonts, anaspids, and conodonts, and involve confirmation of biostratigraphic zonation as well as significant revisions to accepted stratigraphy. Other manuscripts were published as a special 1999 conference issue of Acta Geologica Polonica 49 1-2and elsewhere.
Papers dealing with new taxa and assemblages included one by Pierre-Yves Gagnier et al. on a new acanthodian found in Lower Devonian strata of northern Canada during IGCP 406-related field work in 1996. Marcus Otto reported a new antiarch from the Devonian of Ellesmere Island, Arctic Canada, while Daniel Goujet demonstrated higher than expected diversity of placoderms after IGCP 328 - sponsored field work in 1994 and 1995 in the Canadian Arctic Archipelago. Bob Carr and Elga Mark-Kurik presented their joint research on systematics and palaeogeography of arthrodires, and Elga reported 7 chronological placoderm assemblages in the Lower and Middle Devonian of Severnaya Zemlya. Olga Afanassieva illustrated her recent findings on osteostracans from Severnaya Zemlya. Tiiu Märss et al. correlated thelodont-bearing Llandovery-Wenlock boundary beds of Selwyn-Root and Franklinian basins. Hans- Peter Schultze announced exciting findings on the early actinopterygian fish Dialipina, based on IGCP 406-related field work at the Anderson River, northern Canada, in 1997. Valya Talimaa compared Silurian and Devonian vertebrate faunas in the Circum- Arctic region and found that the late Silurian - early Devonian vertebrate assemblages from Timan-Pechora, Northern and Polar Urals, Novaya Zemlya and Severnaya Zemlya belong to Young's (1981) Cephalaspid Vertebrate Province, pointing to the close relationship of these regions to the Baltica and Laurentia palaeocontinents. On the other hand, the Early Devonian vertebrates from Taimyr and Novosibirsk Islands represent the Amphiaspid Vertebrate Province characteristic of the Siberian palaeocontinent. Data from distribution of shelly fauna and conodonts

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