Stanowisko warstwy kostnej ("bone bed") w "warstwach falistych" dolnego wapienia muszlowego południowego obrzeżenia Gór Świętokrzyskich w Wolicy koło KieIc

Abstract

A BANE BED FROM THE "WELLEN-BEDS" OF THE LOWER MUSCHELKALK (LOWERMOST ANISIAN) AT WOLICA NEAR KIEICE (HOLY CROSS MTS.) Summary The paper presents preliminary results of studies on a bone bed found in Lower Muschelkalk section at Wolica near Kielce (Swiętokrzyskie Mts, Central Poland). About 20 m. thick series of thin-bedded limestones with clayey partings is exposed at Wolica. The limestones have nodular or pseudo-nodular stratification of the “compactional boudinage" type. They were assigned on lithostratigraphical premises to the "Wellen-Beds" of the Lower Muschelkalk by Senkowiczowa (1957a, 1970), and more recently to the lower part of the Lower Anisian by Trammer (1972), on the basis of conodonts. The bone bed, 10 cm thick, represents gray salty clays with marly micritic limestone lenses, and may be regarded genetically as condensation bone bed sensu Aepler and Reif (1971). This bone bed is characterized by mass occurrence of fish remains - teeth, scales, ichthyodorulites, finrays, vertebres, fragments of jaws, etc. (with no overrepresentation of teeth and scale). The fossil fish assemblage of this bone bed may be biostratonomically classified as quasiautigenic thanatocoenosis, composed mainly of “fossils from the same environment" (Boyer, 1973) and some subordinate admixture of fossils probably removed from older deposits or derived from another (synchronous) environment. It may be assumed that generic and specific composition of that assemblage is very close to the primary fish biocoenosis. The fish fauna is almost exclusively represented by Selachii (Elasmobranchii, Chondrichthyes) and Actinopterygii (Osteichthyes). The preliminary list of Selachii comprises 4 genera and 6 species of the family Hybotontidae Owen 1846 (Polyacrodus polycyphus (A g.), Palaeobates angustissimus A g., Hybodus plicatilis A g., H. raricostatus A g., Acrodus gaillardoti A g., A. lateralis A g.) and some hitherto unidentified genera and species of the orda Cladodontiformes and Xenacanthiformes. Among Actinopterygii, representatives of the subclass Chondrostei (orda Palaeonisciformes, Perleidiformes, Saurichthyiformes) predominate. Several species of the genera Colobodus and Saurichthys are probably represented here, similarly as the genera Gyrolepis and Dollopterus, Subclass Holostei is represented by innumerous forms probably belonging to the order Semionotiformes (?Semionotus sp., ?Lepidotes sp.). A detailed paleontological study of the fish fauna is in progress. The fossil ichthyofauna of the bone bed in question shows distinct Lower Mesozoic features and may be of certain stratigraphic value. Bone beds of that age were not as yet reported from Poland. The bone bed discussed above appears to be one of the richest Lowermost Anisian fish "Fossillagerstätte" of the Triassic epeiric basin of Europe.