Kovács I. (szerk.): A Magyar Természettudományi Múzeum évkönyve 78. (Budapest 1986)

Farkas, H.: The variability problem of Schuleridea (Aequacytheridea) perforata (Roemer, 1838) (Ostracoda; Eocene)

ANNALES HISTORICO-NATURALES MUSEI NATION ALIS HUNGARIC1 Tomus 78. Budapest, 1986 p. 41-47. The variability problem of Schuleridea (Aequacytheridea) perforata (Roemer, 1838) (Ostracoda; Eocene) by H. FARKAS, Budapest Abstract — Tables containing 836 measurements taken from 38 specimens of 3 populations representing Schuleridea perforata demonstrate that the variability of any given population is by far not so great as it is suggested in the various papers of the technical literature. With 2 figures. The species Schuleridea perforata deserves special attention from several respects: 1. it is quite frequent in Eocene coal-bearing strata, 2. it occurs in masses in samples, 3. the shell is hard, vitreous and frequently well-preserved, 4. since it is not heavily ornamented, its outline may be measured with precision. With 2 figures. The problems concerning the species The variability problem concerning this species is as old as the species itself GY MÉHES wrote the following: "Greatly variable There are short, robust as well as long, elongate forms It is quite likely that Cytherideaperforata evantually may be split up into several independent species". M MONOSTORI said : "The shape of the valve-outline and the length /height ratio are rather variable.

.. The analysis of the Dorog Basin material clearly shows that the distinguishing of the subspecies is of no use.

.. Some forms are thicker and higher; these are probably the females " Thus, it seems quite obvious from the above-mentioned that by solving the problems this species may play significant role in the examination of the Eocene strata, especially from paleoecological point of view. The problems may be grouped under the following points: 1 If the suggestion that the higher form is the female, and the lower one is the male is true, then the two forms had to be (?) separated without transitional forms. 2. The authors note without exeption: "The shape of the shell is rather variable " However, we do not know up to now what this "variability" means It is quite possible that variability is great within any one given population. Another possibility is that the specimens of a population are almost identical, but almost every population differs from any other one. We do not know what the extreme length/height ratio values are, how large the given absolute value are It goes without saying that I could not solve all the problems. This time I examined only a small number of specimens My present examinations involved the measurements of both the left and the right shells, and concentrated exclusively on well preserved specimens, of which there are not many In the majority of the cases the right and the left shells remained together, and are in fact inseparable. The specimens are still measurable; my plan is to carry out a thorough biometrical investigation on a large number of samples. Material examined DR. T. KECSKEMÉTI, Director of the Palaeontological Department of the Hungarian Natural History Museum, Budapest, was kind enough to allow me to study a very valuable material originating from Eocene strata. I should like to express my heartful thanks to him at this place. I selected three samples from this material, all deriving from Many, Hungary. Though subsequently I make reference to the lables of DR. T. KECSKEMÉTI, in the tables I refer to the samples simply as 1 Many, 2. Many, 3. Many. The data are as follow: 1 Many: A/8, Many 4, 556.9-560.8 2. Many: A/39, Many 54, 259.4-262.0 3. Many: A/23, Many 54, 263.0-265.5