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

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

5. The innermost wall of the stony endocarp is covered by a texture which consists of 3-4 series of flat, circular cells, it is usually missing in the fossil specimens. Different textural layers among the recent species can be well distinguished, however, to a different degree. According to the data available so far they are characteristic for the species. In case of fossil finds the investigation of the finer structure is considerably hindered by a subsequent mineral precipitation which fills in the cavities. At any rate, the total picture magnified 90 times as well as SEM pictures magnified 3000 times of the outer, middle and inner thirds of the wall of the stone demonstrate that the structure of fossil specimens in every case is simpler and more compact than that of the recent ones (Plate VI- VII). To illustrate this statement, the average dimensions of the textural cavities of the three layers are summarized in the following table: morphotype taxa -(-locality outer middle inner [im [im [im pill (Rudabánya) 4-5 6-7 5-7 pill (Csákvár) 5-7 5-7 5-7 torpedo (Rudabánya) 3-4 4-6 4-6 torpedo (Polgárdi) 3-4 7-8 4-5 oval (Rudabánya) 2-3 1-2 1-2 pillow (Csarnóta 2/2) 7-8 10- 12 14- 15 pillow (Tarkő 1) 6-7 3-4 4-5 macro (Rudabánya) 10- 12 4-5 3-4 C. australis 15-20 5-8 7-8 C. tournefortii 5-8 4-7 3-4 C. sinica 25-14 8-13 7-8 C. africana 20-22 13- 14 7-8 C. occidentalis 2- 10 15-20 5-10 The pill and the torpedo morphotypes are definitely uniform just like oval one which is the most compact of all. The pillow type, which has a greater cavity dimension, is already slightly heterogeneous moreover the dimensions of the textural elements of the macro type decraes toward the interior. The same can be observed among the recent species investigated, except in C. occidentalis of NorthAmerica. Besides genetic factors climatic conditions and also stone dimensions influence the structure of the stony endocarp. Consequently the thin walls and the great compactness of the oval morphotype can be traced back to genetic factors. The uniform compactness of the older specimens of several small-sized morphotypes can be traced back by all means to a climate without extremities in temperature. The initial textural isolation of Pleistocene specimens is the opposite process. The large size of the macro morphotype in itself refers to a textural homogeneity. Evolution of the morphotypes In the Rudabánya sample, stratigraphically the oldest of the series, all the six morphotypes which can be observed in the younger samples, can be distinguished. Similarly all, the five basic surface pattern types are present among the oldest finds. Except pill morphotype all the other types are small-sized at the beginning, later however during their development they become increasingly larger. The complicated character of the surface pattern and the structure of the stony endocarp becomes more pronounced from older finds toward younger ones. At the time of their extinction in the Carpathian Basin during the Upper Pleistocene, the Celtis morphotypes had not yet reached the evolutionary level which is characteristic for the extanct species. Consequently, we suppose that the fossil morphotypes cannot be included in any recent species. We can state only that the pill morphotype which disappeared by the end of the Pliocene was related to Celtis africana, while the sphere type was related to Celtis tournefortii. The oval types have the closest relations with the C. australis form group. The torpedo morphotype is similar to C. sinensis, however, because of the phytogeographical distance