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

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

— The middle stage of spiral growth in the microspheric generation is typical of the individual species, while the joint presence of all three stages in informative of the general development level of the species involved. On the basis of the latter, the position of a taxon in a phylogenetic lineage can be determined (SCHAUB 1963). In studying the evolution of the genus some fundamental statements of ABRARD (1928) have been relied on: 1. the ancestral form of each Nummulites lineage is nongranulate; 2. both granulate and nomiranulate taxa can evolve from the ancestor; 3. a nongranulate form can never develop from a granulate taxon; 4. the principal trend of nongranulate taxa: loosely coiled, irregular spire -*• tightly coiled, regular spire -+• loosely coiled, irregular spire with operculinoid chambers. Along with these main ontogenetic and phylogenetic regularities, several relationships and regularities have been observed of which the following are most important. — In every phylogenetic lineage or branch, evolution includes two components: a progressive element and a regressive one. Progressive elements: spire becoming more tightly coiled, length growth of chambers, increase in diameter of test and megalosphere, thickening of marginal cord, increase in number of septa, septal lines becoming complicated in behaviour and appearance of granulation. Regressive elements: loosening of spire, thickening of chambers, reduction in diameter of test and megalosphere and degenerative phenomena. Trend, character and rate of evolution are determined by the ratio of the progressive elements to the regressive ones. — The evolving new taxa are brought about, as a rule, by divergency. I such cases an cvolutionarily plastic (for the most part variable) species will carry only the general trend of evolution of the characters and will give rise, as a result of the influence of various evolutionary factors (dispersal, isolation, selection, floating, etc.), to new taxa. This fact accounts for the great deal of ramifications in Table 1. Transformation of a species (anagensis) with the passing of time is less frequently observable. — Taxa evolved upon influence of geographical and environmental factors are relatively abundant. Deviations from the stocktaxon are usually not too large, being usually limited to subspecific level. This indicates that the individual populations must have been more or less interconnected. In the particular case of the Bakony Mountains area, all these circumstances are in connection with the local and temporary existence of an archipelago and with a high variability of facies. Partly the statements published earlier and partly the observations made during the present study have given clues to our formulation of such a scheme of phylogeny as is attempting to outline the linear and collateral relations of the individual species by relying on the dynamism of evolution. In drawing up his phylogenetic scheme, the writer did not restrict himself to considering the Bakony Mountains material, but he has considered all the Hungarian species and a wealth of foreign comparative material (16 topo- and 2 holotypes from among the latter!) as well. The number of taxa included in the scheme is 109, of which 66 Hungarian (including 52 from the Bakony) and 43 foreign. In addition to the studied material, special attention was paid to publications that had given phylogenetic schemes. First of all, the schemes proposed by SCHAUB (in: HOTTINGER, LEHMANN & SCHAUB 1964), NEMKOV (1967), BLONDEAU (1972) and GOLEV (1978) were taken into consideration, especially as far as the early states of evolution of Nummulites (Ilerdian, Cuisian) were concerned. The fact is that the deposits that comprise these stages are either fully unrepresented in this country, or their representation is limited to their upper members. For these intervals, the details were borrowed, as a rule, without any modification or change, from one or another of the afore-mentioned schemes. The control, however, was provided by more than 20 species, here too. Some important species, missing from the writer's collection, but important from the phylogenetic point of view, have been borrowed, without a control, from one or another of the afore-mentioned schemes. Regarding certain details, the writer has relied, in addition to some of his earlier observations (KECSKEMÉTI & VANOVÁ 1972, KECSKEMÉTI 1974), on the data of HARPE & ROZLOZSNIK (1926), GOLEV (1956), MAMEDOV (1967), PAVLOVEC (1969 a, b) and MREVLISHVILI (1978). In developing his scheme, he has been pursuing three goals: •— to include the Hungarian Nummulites species in the phylogenetic scheme of the Nummulites ; — to insert single missing links in some lineages; — to carry out some correction, where necessary, in existing schemes. The author's scheme is given in Table 1, where the taxa of Hungarian occurrence are capitalized, the foreign taxa are given in lowercase and the taxa that are genetically important but are missing from the author's collection are indicated by lowercase letters in brackets.