Nógrád Megyei Múzeumok Évkönyve XXIV. (2000)

Tanulmányok - Természettudomány - Hír János: Korai miocén hód - Steneofiber depereti MAYET, 1908 - előfordulása Zagyvapálfalván

The occlusal surface of the M1-2 molar is divided by the hypoflexus and the mesoflexus. The latter one is strongly curved baskwards. In the lengthening of the hypoflexus there is a large enamel islet: the parafosette. In the posterior part of the surface there is a smaller enamel islet: the metafosette (figs. 6.,7.). Measurements: L: 5.25 mm, Wa: 5.6 mm, Wp: 5.3 mm, Hh: 5.3 mm. The structure of the occlusal surface of the M3 molar is similar to the M 1-2 with the following différences: the hypoflexus is not so deep, the mesoflexus is not curved backwards, behind the parafosette there is a smaller enamel islet: the subparafosette (fig. 7.). Measurements: L: 5.0 mm, Wa: 5.2 mm, Hh: 4.9 mm. Cement is not found in the flexids and in the flexus. In the upper molars the early stádium of the root -formation is visible. The hypostria and the hypostriid never reach the basis of the toothcrown. The stratigraphie context The layers no. 1,2,3 of the locality section (flg. 2.) belong to the Zagyvapálfalva Clay Formation (HÁMOR, 1985). The litostratigraphical unit constituted by terrestrial or fluvial purple -red or greenish -grey clays, reddish -brown silty clays, argillaceous silts, greyish -white sands, unconsolidated sandstones, sandy gravels and coarse -grained conglomérâtes. The "Footprint Sandstone" of Ipolytarnóc has also been included intő this formation. The geographical range of the unit is limited to Northern Hungary and Southern Slovakia. The Zagyvapálfalva Clay is very poor in fossils, only sporadic vertebrate finds were deseribed in the Hungárián geological literature (HÁMOR, 1985, KORDOS 1985), eg. Prodinotlierium sp., Mustodon sp., Rhinocerotidae indet., Lagomeryx sp.1 The studied lithostratigraphical unit is overlyed by the Gyulakeszi Rhyolite Tuff in the Nógrád Basin. Radiometrie date was published írom the tuff: 19.6 +-1.4 million years. The samples were collected fom the surroundings of Kazár village, near to the Steneofiber locality. After HUGUENEY (1999) the S. eseri -S. depereti transition came to pass during the Early Miocène MN 3 zone, 18 -20 million years ago. The Hungárián find seems to be synchronous or a bit earlier, than the oldest W-European 5*. depereti materials. 150