Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 79. (Budapest 1987)
Kecskeméti, T.: Contributions to the phylogenetic connections of Nummulites species
existing in Ilerdian and Early Cuisian times, disappears without giving rise to a direct descendant (SCHAUB 1951; HOTTINGER, LEHMANN & SCHAUB 1964). Both NEMKOV (1967) and BLONDEAU (1972) derive N. rotularius from N. deserti, but whereas NEMKOV does so along a direct line (otherwise extending the stratigraphie range of the species to span the Middle Eocene as a whole), BLONDEAU suggests the presence of N. praecursor in between. To formulate his opinion, the present writer has had to rely on N. deserti specimens, as no comparative N. praecursor material has been available to him. For this reason, in the present scheme, N. rotularius is considered, with some reserve though, as a form that became an independent species already at a very early stage of evolution of Nummulites and that, evolving through Late Ilerdian and Early Cuisian times, persisted up to Late Cuisian time. It was from this taxon that the present writer's A 7 , aff. rotularius from Devecser (KECSKEMÉTI 1973) evolved as a result of increasing specialization. (This statement is in agreement with the well-known fact that the first culmination in the evolution of Nummulites is reached, with markedly specialized taxa, at the end of the Cuisian.) No form that would represent a follow-up along this lineage has been found as yet among the Lutetian Nummulites from Hungary. N. discorbinus group Adopting the concept of BLONDEAU (1972), the present writer is of the opinion that the members of the N. discorbinus group derive collaterally from N. globulus. The features of resemblance between the Ilerdian —Cuisian N. globulus and the Upper Lutetian taxa of the group are really recognizable, but this relation has become loosened to the extent that the inclusion of an intermediate taxon in between is required. This species must have been characterized by marked evolutionary plasticity. Having got strongly differentiated by about the middle of the Lutetian interval, it could serve as a starting point for several taxa (given with a question mark in the present scheme). Having appeared with minor shifts in time, these forms reached a species-level independence by Late Lutetian time. Of them, N. discorbinus and N. discorbinus minor have been known for a long time now. N. majzoni, N. zircensis and N. iohannis have recently been described (KECSKEMÉTI 1970). The characteristic features they have in common include an inflated shell covered by radial septal lines, a ragular spire and a thick marginal cord. Some of the other characters (shell size, presence or absence of a central pillar cone, curvature of septa, shape of chamber) represent excellent differential diagnostic features for the individual taxa, but they include none that should be of a convincingly progressive trend. Thus all the present writer has been able to detect by most scrutinized studies is that the above taxa of the group derive from a common ancestor that lived in a near past, being very closely related to one another and that they co-existed as parallel species during their comparatively short phylogenetic career (the range of N. discorbinus having been the longest of all). Consequently, GOLEV'S derivation of N. zircensis from N. rotularius, form belonging to a completely different group, is not sufficiently well founded (GOLEV 1978). N. partschi —lorioli —fabianii group The origin of the taxa belonging to the N. partschi —lorioli —fabianii group can be traced back to the Ilerdian N. praecursor. This one gave rise to N. partschi, one of the most important taxa for the understanding of Cuisian phylogeny. During the Cuisian, N. partschi can be observed to have undergone some changes in the pattern of granulation, a trend towards reaching perfection, but this change is manifested on a subspecific level at the most. A lower degree of this improvement is represented, in the Early Cuisian, by N. partschi gram fer, fol-
