Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 79. (Budapest 1987)

Kecskeméti, T.: Contributions to the phylogenetic connections of Nummulites species

N. britannicus is distinguished by its uniform, though much more rapid, coiling, its closely spaced and less inclined, but heavily curved septa and its nearly twice higher than long chambers from coeval N. laevigatus —• features positioning it on the loosely coiled branch of the group. The collateral Lower Lutetian N. hagni is also characterized by a loosely coiled spire and, in terms of its growth rate and chamber index, it is intermediate between N. laevigatus and N. britannicus (PAVLOVEC 1969b). These two loosely coiled taxa from the deeper Lutetian do not occur in the Hungarian profiles. The first Hungarian representative of the branch provided with a loosely coiled spire is N. penzesgyoerensis (KECSKEMÉTI 1970) described quite recently. Its characters suggest a close relationship with N. puschi. With a view to the diameter of test much smaller compared to N. puschi, to the smaller megalosphere and the more simple spiral pattern and also to a stratigraphie position that, in the majority of the cases, predates N. puschi, the idea that N. penzesgyoerensis is a forerunner of N. puschi might be brought up. Their concurrence within a narrow interval in some profiles, however, makes it rather probable that these two taxa developed along two parallel lines, having departed from a common taxon much earlier. This situation is illustrated by the present writer's scheme and the same conclusion was arrived at by GOLEV (1978) during his study of specimens from the Bakony Mountains. This common taxon is unknown for the time being, but, given the great time interval between N. britannicus and N. puschi, it may well have come into being in that span of time. This probability is supported by the two most detailed phylogenetic schemes in which the phylogenetic hiatus is filled up by a taxon referred to as "n. sp." (HOTTINGER, LEHMANN & SCHAUB 1964; BLONDEAU 1972). In point of fact, the time-span under consideration may be filled, at least in part, in such a way that the stratigraphie range of N. penzesgyoerensis is widened by the discovery of new and stratigraphically deeper-situated occurrences. The fact is that this species has been recovered, since its first description, from an ever increasing number of profiles in which it spans a wider stratigraphie range as compared to the original information. The end-member of the loosely coiled Upper Lutetian branch is N. puschi, a form of great size representing the loosely coiled equivalent of N. brongniarti. Its indirect connection with N. britannicus is indicated in every phylogenetic scheme, but, as far as the taxon that might assure this connection is concerned, only hypotheses are available, as evident from the foregoing. Thus further research to explore it is needed. With N. puschi, the loosely coiled branch gets extinct, so that none of the species of the laevigatus-group passes the Middle/Upper Eocene boundary. N. distans

—irregularis group Comprising several lineages, the members of this group exhibit rather diversified characters. One of the characters of its Lutetian members, the large, often gigantic, size is a feature they all have in common. Of the lineages, the most homogeneous one, that of distans, is represented in this country. The first member of the lineage is N. bolcensis, an Ilerdian species that sprang from N. fraasi nearly simultaneously with N. laxus. Its next members are forms of ever increasing size such as the Cuisian .V. nemkovi, followed by N. distans and N. polygyratus, respectively. Between the latter two species there is a close relationship as reflected by a comparatively thicker marginal cord and a more loosely coiled spire: two important features they have in common. The looseness of spiral coiling in N. polygyratus is somewhat stronger. A divergence of opinions on the nature of the relationship is reflected by the schemes of SCHAUB and BLONDEAU, respectively. In the former case N. polygyratus succeeds to N. distans along a direct line (HOTTINGER, LEHMANN & SCHAUB 1964), in the latter case, the two species evolve 5 Term. Tud. Múz. Évk. 1987.