New Miocene (Ottnangian) Teredolites from the Nógrád lignite basin

Abstract

In this paper fragments of driftwood, containing traces of wood-boring bivalves, and their position
within the sequence described. Traces of riftwood can be found at the coal-bearing series of Kerek-Bükk
which is part of the Kazár Székvölgy open cast mine. Driftwood with traces of wood-boring bivalves had
earlier reported only from the overlying or (rarely) underlying formations of the coal-bearing series of
the Nógrád Basin. The two driftwood fragments (A and B) are situated under the underlying sandy
sediments of coal seam number two. The measurements of the driftwood A are remarkable: length 580
cm, width 84 cm. On the basis of the morphological characteristics of the borings the following two
ichnotaxa have been distinguished: Teredolites clavatus and Teredolites cf. clavatus. The borings of the
Teredolites cf. clavatus ichnotaxon are thinner and longer compared with the measurements given in the
literature. Their length/width ratio is alsó bigger (9) instead of 5 (KELLY and BROMLY 1984).
Considering the differences in the size of the borings and the density of the apertures three
generations of wood-boring bivalves can be assumed.