Hints, O., 1998c

Author(s):Hints, O.
Title:Late Viruan (Ordovician) polychaete jaws from North Estonia and the St. Petersburg Region
Journal:Acta Palaeontologica Polonica

An abundant, diverse and well-preserved fauna of jaw-bearing polychaetes (Annelida, Polychaeta, Eunicida) was recovered from the late Viruan (Caradoc) of eight borehole sections in North Estonia and the St. Petersburg region. Altogether 46 species are encountered. Two new genera, Incisiprion with type species I. incisus (Kielan-Jaworowska, 1966) and Estonioprion with type species E. maennili sp. n., and five new species (Incisiprion edentulus, Polychaetura kielanae, Ramphoprion bialatus, Ramphoprion peterburgensis, Estonioprion maennili) are introduced. In addition 17 new species are described under open nomenclature. The taxonomy is based on jaw apparatuses, fused or reconstructed ones. Many species found in Estonia have been previously described from the erratic boulders of Poland. The studied polychaete fauna was confined to the North Estonian Confacies, a shallow-water carbonate shelf, which constituted favourable habitats for Ordovician polychaete worms. The stratigraphical ranges of many prevalent polychaete species exceed the interval studied. However, a few species seem to be restricted to particular horizons and may be useful for stratigraphy. Polychaete assemblages of certain time intervals, characterized by very steady species composition and relative frequencies of different taxa, were spatially widespread within the North Estonian Confacies. Based on the changes in the assemblages, some stratigraphical levels, like the boundary beds of the Idavere and Jhvi stages, can be traced within the study area. The jawed polychaete faunas of Baltica and Laurentia probably had several species in common during the Caradoc.

Keywords:Baltic Basin, Baltoscandia, Estonia, Ordovician, paleontoloogia, scolecodonts, Upper Ordovician, Viruan
New genera described:1. Incisiprion Hints, 1998
2. Estonioprion Hints, 1998
New species described:1. Ramphoprion bialatus Hints, 1998
2. Incisiprion edentulus Hints, 1998
3. Ramphoprion peterburgensis Hints, 1998
4. Estonioprion maennili Hints, 1998
5. Pteropelta kielanae (Hints, 1998)
6. Xanioprion sp. A Hints, 1998
7. Xanioprion sp. B Hints, 1998
8. Oenonites sp. A Hints, 1998
9. Oenonites sp. B Hints, 1998
10. Ramphoprion sp. A Hints, 1998
11. Ramphoprion sp. B Hints, 1998
12. Ramphoprion sp. C Hints, 1998
13. Kalloprion sp. A Hints, 1998
14. Leptoprion sp. A Hints, 1998
15. Polychaetura kielanae Hints, 1998

Specimens with photos

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