Holothurioidea i Ophiuroidea w dolnym wapieniu muszlowym z otworu wiertniczego Żebrak

Abstract

HOLOTHURIOIDEA AND OPHIUROIDEA IN THE LOWER MUSCHELKALK FROM BORE HOLE ŻEBRAK

Summary

The occurrence of holothurian sclerites in the Triassic deposits of Poland has for the first time been reported by K. Zawidzka (1970), who has found them in the Gorażdże Beds and in the Terebrlatula Beds in the Opole region (Fig. 1). Holothurian sclerites have also been found at Dziewkowice, Upper Silesia, by H. Kozur and H. Mostler (1970).

In bore hole Żebrak (Fig. 1) approximately 280 sclerites have been found by the present author in the beds with Lima striata (upper part of the Lower Muschelkalk), which are an equivalent of the Terebratula and Karchowice Beds from Upper Silesia. The author has determined: Eocaudina? sp., Tetravigra sp., Uncinulina sp. (aff. U. angulata F r i z z e 1, E x 1 i n e), Achistrum issleri (C r o n e i s), Priscopedatus sp. (aff. P. kotlickii K o z u r, M o s t 1 e r), Priscopedatus sp. (aff. P. tyrolernsis M o s t l e r), Theelia zapfei K o z u r, M o s t l e r, Theelia cf. zapfei Ko z u r, M o s t l e r, Theelia multiradiata K o z u r, Theelia cf. subcirculata M o s t l e r, Theelia sp. K o z u r, M o s t l e r, Theelia sp. (aff. T. germanica K o z u r), Theelia n. sp. In the described association the representatives of the genus Theelia predominate, and sclerites that belong to other genera amount barely to about 4 percent.
The assemblage of sclerites found to occur at Żebrak resembles most .of all that described by H. Kozur and H. Mostler (1970) from Dziewkowice, Upper Silesia. The resemblance consists in the common occurrence of the representatives of Theelia sp. K o z u r, M o s t l e r, T. zapfei K o z u r, M o s t 1 e r and T. cf. zapfei K o z u r, M o s t l e r. The difference in turn consists in a scarce participation of other genera, and in the occurrence of genera and species that are not known to occur in the Upper Silesia area. Here belong: Priscopedatus sp. (aff. P. tyrolensis M o s t 1 e r), Theelia sp. (aff. T. germanica K o z u r), Theelia cf. subcirculata M o s t l e r, and Theelia multiradiata K o z u r. These species has so far been known from the Triassic of the Tethys, and from the lower members of the Muschelkalk in Thuringia.
Among the representatives of Theelia sp. are found also specimens determined by the present author as Theelia n. sp. Their sclerites are characterized by the greater height than that of the specimens so far described a bad preservation state of these specimens makes any more detailed description impossible. As concerns forms, so far not reported from the epicontinental Triassic can be mentioned: Eocaudina? sp. and two species of Uncinulina sp.
At Żebrak, the Holothurioidea occur along with the fragments of ophiuroids, juvenile terebratulae, columnals of crinoids, spicules of echinoids, numerous representatives of Spirorbis valvata, ostracods, foraminifers and fish remains.
The comparison of the observations made by H. Kozur and H. Mostler (1970) with those obtained at present at Żebrak leads to a conclusion that the research of the Triassic Holothurioidea found in the epicontinental basin are now still in a stage, in which any occurrence site throws light on their stratigraphical ranges and geographical distribution.
As far as the work of H. Kozur and H. Mostler (1970) is concerned the introduction of new names of Alpine stages and sub-stages for the Central-European (= German) Triassic seems to be groundless. A precise comparison of both sections is very important, but the deposits of the basins considered should be left, with their own subdivisions, as long as possible till new common stratigraphical criteria, based on the detailed palaeontological examinations, will be worked out. As yet, all elaborations of macrofauna, as well as of conodonts, holothurians and algae did not satisfy these conditions.
A fact that H. Kozur and H. Mostler (1970) relate the Terebratula Beds from the Upper Silesia to the Pelsonian can also be called in question here. In the Upper Silesia, in the Gorażdże Beds (Table 1), Paraceratites trinodosus M o j s i s o w i c s (P. Assmann, 1937, 1944) occurs, which is a guide species for the uppermost Anisic stage. In consequence of this, the Terebratula Beds, which rest above the Gorażdże Beds, should be referred not to the Pelsonian, but to the Illirian.