Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 77. (Budapest 1985)

Kordos-Szakály, M. ; Kordos, L.: Morphotypes of Hungarian fossil Celtis (Urticales) stones

The chronological development of basic surface patterns is well represented by the following list which contains the frequency of basic patterns in the stratigraphical order of the localities without denoting morphotypes : localities basic patterns localities í. 2. 3. 4. 5. Rudabánya 64% 23% 6% 7% Csákvár 33 66 — — — Tardosbánya 40 60 — — — Polgárdi 70 20 10 — — Osztramos 1 80 20 — — — Csarnóta 2 26 26 7 26 15 Osztramos 7 — 89 — 2 9 Osztramos 8 24 64 — — 12 Podumci — — — — 100 Tarkő 16—13 — 48 — 48 4 Tarkő 11 — 18 — 82 — Tarkő 1 — 48 52 On the basis of these two lists the following phenomena can be observed beyond doubt : The most simple basic pattern No 1 and its developed variant (basic pattern No 2) are characteristic first of all for older (Upper Miocene, Pliocene) morphotypes ; basic pattern No 1 (without crests) is already absent from the Middle and Upper Pleistocene samples of the areas investigated. Basic pattern No 3 is only an extreme variant. Complicated basic patterns No 4 and 5 are absent among the early specimens of ancient pill and sphere morphotypes. From the Middle Pleistocene till the extinction of the Celtis genus in Central Europe basic patterns types No 2 and 4 were the unambiguously characteristic types. Consequently the variability of patterns is already present among the oldest finds but its advance depends on the evolution of morphotypes. A development from simpler types towards complicated ones is a common phenomenon. Microstructure of the morphotypes A study of the stony endocarp of Celtis was carried out in the Hungarian Geological Institute with the aid of a scanning electron microscope (SEM). Both the structure of the outer surface and the cross sectional textural structure of the stony endocarp were investigated. Among fossil specimens the outher surface is frequently eroded, while among recent ones it is contaminated by the crusted texture of the soft part adhering to it. Therefore we could not determine the texture in certain cases. On the basis of the patterns which are suitable for an analysis (Plate IV: 1-6), we can state beyond doubt that the outer surface of the stony endocarp is usually built up of hexagonal units of 25-30 [xm dimension. In this respect we could not observe any difference between the different morphotypes and the recent species. The thickness of the stony endocarp varies between 0.05-0.1 mm. In cross section, among the recent species several types of textures can be distinguished from the surface part towards the interior. In generalized form they are as follows (Plate V.) : 1. A crust 40-50 u,m thick consisting of flat circular cells 1-3 [im thick. This is the crusted residue of the soft part. 2. A loose layer of considerably varied thickness (22-250 [zm) consisting of polygonal, isometric cells of 10-20 ptm diameter. This layer constitutes the surface pattern. 3. The middle and at the same time the thickest zone of the stony endocarp is built up of compact textural elements (brachyosclereida) of 4-5 urn diameter. At the place of the main crests it is slightly thickened. 4. Towards the interior part of the stone there is a layer built up of units of 3-4 urn. It slightly differs from the previous layer, namely it is more compact though there is no sharp difference between them.