Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 77. (Budapest 1985)
Kordos-Szakály, M. ; Kordos, L.: Morphotypes of Hungarian fossil Celtis (Urticales) stones
it can only imply only a parallel development. The recent species related to the pillow and the macro morphotypes cannot be demonstrated at present. With the aid of the analysis of the morphotypes, size data and the collected chronological representation of the surface pattern types, a so-called stratophenetic phyletic tree of the investigated Celtis species can be erected (Fig. 5). This phyletic tree was created by GINGERICH (1979). Along its vertical axis there is a timescale (with the chronological position of the different localities registered on it) while along its horizontal axis there are some characteristic measurements (here the height of the stony endocarp) and the frequency of the surface pattern types. By the application of this scheme the true ancestral and succession lines, and phylogenetic relations are placed correctly. The complex evolutionary analysis of Celtis morphotypes demonstrates their development as parallel with each other. Within this development the most important, rapid changes in dimensions and pattern types as well as the disappearance of certain morphotypes (pill and macro types) took place at the Plio-Pleistocene boundary. Before reaching this boundary there was a very slow, balanced development while in this short period an acceleration took place followed during the Pleistocene by another period of slower evolution. This development is in general congruent with the "punctuated equilibrium" theory of evolution recently created by GOULD (1983). Biozonation based on the study of Celtis stony endocarp With knowledge of the history of the last 10 million years and the characteristic evolution of Celtis stony endocarp, we can erect a biosfratigraphical division which is unique in paleocarpological practice. Basically two phylo-biozones and within them six subzones can be distinguished (Fig. 6). Celtis "pill" biozone: Every morphotype can already be demonstrated, though it is the pill type which is constantly present and dominant. At the end of the zone it disappears, presumably together with the macro type. The morphotype of the pill began to be smaller and statistically more primitive in its pattern towards the younger ages. It covers the period between the beginning of the Lower Pannonian and the Plio-Pleistocene boundary. Celtis "primitive" s u b z o n e : It is the older member of the Celtis pill biozone where all the morphotypes are small-sized and have a still simple surface pattern. It includes the Upper Miocene (Pannonian) and the beginning of the Pleistocene. Celtis "m aero" subzone: At the boundary of the two zones marked by the change of the pill and the sphere morphotypes the frequency of the macro type increased at several localities. This characteristic period lasted from the Middle Pliocene till the Plio-Pleistocene boundary. Celtis "sphere" biozone: Sphere was the dominant morphotype of this zone. On contrary to the pill biozone, pill and macro types was absent, towards younger ages the frequency of the different morphotypes increased, their surface pattern became more complicated and individually characteristic. It covers a period from the Plio-Pleistocene boundary till the disappearance of Celtis in Central Europe —or as regards SE Europe we are still in this subzone. Celtis "revolution" subzone: In this period the surface pattern of the different morphotypes was highly variable ^while their dimensions had not changed yet compared to those observed in the previous biozone. It can be correlated with the Lower Pleistocene.
