Górnojurajskie Triaxonia z okolic Częstochowy

Zofia Fibich


Upper-Jurassic Triaxonia of the Częstochowa Region (Central Poland)

In the Częstochowa region there occurs an aboundant sponge fauna in sediments of the Lower and Middle Oxfordian. In lower zones of the Lower Oxfordian there are mainly calcareous sponges (Calcarea). Higher, in the Cardioceras bukowskii zone, beside Calcarea, there appear Monaxonia and especially numerous Tetraxonia. Calcareous sponges become rare and gradually disappear in the Cardioceras excavatum zone, and there appear Triaxonia, apart from Monaxonia and Tetraxonia. The sponges of the Triaxonia order collected at Kłobuck, Pierzchno, Jasna Góra and Wrzosowa were listed in the Polish text p. 44 table 1. The vertical repartition of the sponge fauna and its geographical distribution in the investigated region indicates the transgression of the Upper-Jurassic sea, ensuing gradually from NW, as well as the gradual deepening of the sea basin and the transition from the tidal zone through littoral to the batial one. There have been described in the Polish text 19 species of 11 genera of the Triaxonia order. The specimens of the Craticulariidae family are the most numerous ones among the Triaxonia of the Częstochowa region. The Lychniscosa and Hexactinosa superfamilies are represented there. Trochobolus dentatus Kolb — single specimen investigated (PI. VI, Fig. la, b; PI. X, Fig. 2) is suppased to be an immature one. It differs from in the smaller dimensions (height = 1,5 cm; thickness = 0,9 cm; thickness of the wall = 0,2 cm). Trochobolus cf. suevicus S c h r amme n — two specimens poorly preserved. Parenchymal skeleton and dictyonalia are in conformity with those of the specimens Trochobolus suevicus, Schrammen , 1937. Exact identification is impossible, considering the unfavourable condition of the preserved specimens. Phanerochiderma rugosa (Goldf . ) ; Schrammen, (1936, 1937). Three specimens cylindrical in shape. Fragments of the dermal skeleton shown on PI. VII, Figs. 3—5. Cryptochiderma trabeculata (Quenst.) — four specimens investigated are funnel-shaped. A. Schrammen (1936, 1937) also describes cup- -shaped ones. Sporadopyle cf. obliqua (Goldf . ) — single specimen here illustrated (PI. VI, Fig. 2) resembles Sporadopyle obliqua f. curia L. Lagneau-Herenger, 1962, in shape, but the appearance of dictyonalia and the arrangement of ostia better fit the description of S. obliqua (Goldf . ) ; Schrammen , 1937. Sporadopyle cf. nodosa (Quenst . ) — the sponge is described by F. Oppliger (1897) as one growing from one point and then ramifying radially. 29 fragments I had at my disposal could not help to reconstruct the shape of the sponge as a whole. The skeleton pattern, the arrangement of ostia, the shape of fragments and the circumoscular structure resemble to the utmost S. nodosa. Tremadictyon cf. radicatum (Quenst . ) — single specimen poorly preserved. The identification is possible only on the grounds of the parenchymal skeleton structure (PL X Fig. 1). The hexactines are identical with the ones presented by A. Schrammen , (1937) as characteristic of the T. radicatum form. The dermal skeleton has not been preserved in the fossil state. Craticularia subclathrata (Etall.); Oppliger. 1907. — only three fragments preserved, one illustrated (Pl. VI, Fig. 9). Ostia round 1,0— 1,5 mm in diameter arranged in vertical and horizontal rows intersecting each other. Paracraticularia cf. arborescens S c h r amme n — two specimens poorly preserved, one illustrated on Pl. VI, Fig. 6. Round the ostia there appear characteristic aureoles 0,2 mm in breath, build of massive silica (Pl. VIII, Fig. 1) that have never been met in other species. Paracraticularia cf. tubifera S c h r amme n — single specimen rather poorly preserved. The parenchymal skeleton (Pl. IX, Fig. 2) display similarity to that of the specimens P. tubifera, Schrammen , 1937. Casearia articulata (Bourquet) — Two specimens rather poorly preserved (Pl. VI, Fig. 8). The remarkable feature of this species is the structure of dermal skeleton (Pl. VII, Fig. 1, 2) built of stauractins of different size, often thorn-shaped. It forms a consistent cover well preserved in the depression of lateral fold.

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