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

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

The stony endocarp is usually asymmetrically bilateral, the apex and basis are not perpendicular to the imaginary equator of the stone, consequently the thickness of the endocarp is different. Basic forms — morphotypes Fossilized endocarpia of seeds among the stone fruits are suitable for a distinction at species level. Because of the high diversity found in the surface morphology of the Celtis stones, as well as due to the great differences between recent and fossil species, in the first phase of the investigation it is advisable to separate multivariated morphotypes. This method makes possible without taxonomical obligations the determination of morphological types different from each other as well as the determination of the degree their variation taking into consideration several primary and secondary points of view. The establishment of the most probable genealogical connections of the morphotypes would be possible only after an evaluation of recent specimens available in a far greater quantity. For lack of stones it is impradical to use a carpological nomenclature based only on leaf-impressions. One of the significant differences among the stones of recent Celtis species is the basic form of the stony endocarp, that is, the form of the contour line running parallel with the meridional division crest. Celtis australis, C. occidentaloides, C. sinica have oval, C. tournefortii has circular while C. caucasica and C. africana have asymmetrical or barrel-like broadened circular basic forms (Plate 111). Among fossil species six different basic types can be distinguished (Fig. 2-3) "Pill" (Plate I: 1-2): Small-sized globe with a regular circular section. The basis is frequently pointed, the canalis basale can frequently be seen even on mature specimens. The two poles enclose an angle with the equator. The thickness of the wall of the stony endocarp is slightly asymmetrical

. It occurs only in older (Upper Miocene, Pliocene) samples. "Sphere" (Plate 1

: 4 and II : 1-2) : It has a regular spherical structure. It frequently has a slightly bent curve at the basis. The separation stump is frequently pointed on chronologically older and juvenile specimens, while it is missing in specimens from younger epochs. The original form can be deformed, it becomes usually elongated. This morphotype can be demonstrated practically in all samples. "Pillow" (Plate 1:6): Its equatorial diameter is greater than its height between the basis and the apex. It is not evenly ovally elongated but becomes conically narrow toward the basis an widens toward the apex like a sack or a pillow. It has some transitional forms towards the sphere type but in the cases where dimensional differences are also accompained by the basic form they can definitely be distinguished from each other. The stony endocarp significantly thickens at the basis. The planes of the basis and the apex are perpendicular to the equator. This morphotype is frequent in the majority of the fossil samples. "Torpedo" (Plate 1:3): This is a small-sized, highly elongated, inside oval, outside frequently pointed basic form. The wall of the stone is usually symmetrically thickened. At the basis it has a canalis basale which is frequently highly elongated, thickened and broadened. It is frequent in older samples. "Oval" (Plate 1:5): This Celtis stone has a regular oval cross section and an elongated basic form. The basis is light, the separation stump is wide which frequently makes the stony endocarp appear slightly asymmetrical. It has an even, in most cases thin wall. The line between the two poles is always perpendicular to the equator. This morphotype do es not appear frequently, it was however continuously present in the semples. " Macro" (Plate II: 3-4) : This is a conspicuously large irregular asymmetrical morphotype. Usually the basis is not in the centre and an edge is developed in a stripe around the separation stump. In most cases its width along the equator is greater than its height between the poles. It has a very thick uneven wall. It is rarely divided into two hemispheres. This is a morphotype which occurs only sporadically in richer samples. It is possible to group the Celtis stones found in the samples according to the basic forms of the stony endocarps. Torpedo, oval and macro morphotypes can be separated unambiguously while transitional forms can also be observed between pill, sphere and pillow morphotypes. On the basis of the great quantity of recent comparative material available, C. occidentalis and C. australis basic forms have only low diversity. Summarizing the abovementioned facts, we can say that the morphotypes of fossil Celtis species can be determined first of all by their basic forms together with their dimensions and surface patterns as their additional characteristics.