Exquisitely preserved articulated skeletal remains of teleost fishes from the Badenian corallinacean limestone exposed in the Eisenstadt-Sopron Basin, Austria are known since the first part of the XIX century thanks to the efforts of brilliant Austrian naturalists such as Johann Jakob Heckel and Rudolf Kner that described several specimens collected in a few outcrops located in the nearby of the village of St. Margarethen. A vast collection of extraordinarily well preserved fishes and invertebrates from the corallinacean limestone was recently accumulated during two large excavation campaigns carried out in the Kummer Quarry, about 2 km E of St. Margarethen village (47°48’01.76’’N, 16°37’59.12’’E). These fossils, primarily represented by skeletal remains of teleost fishes and subordinately by shark teeth, crustaceans, bryozoans, echinoids, molluscs and brachiopods, are preserved in finely laminated greenish-whitish calcarenitic marls that apparently originated in low-energy depressions of the floor surrounded by carbonate sand build-ups. The mass accumulations of fishes and the thanatocoenoses of authochthonous benthic invertebrates originated in response to repeated hypoxic events. The repeated and severe benthic hypoxic events were probably associated to blooms of Coccolithus pelagicus and some reticulofenestrids triggered by periodic increased input of nutrients. The Late Badenian age of this konservat-lagerstätte has been estimated based on calcareous nannoplankton, which indicates zone NN5b, around the Langhian/Serravallian boundary, roughly between 14.0 and 13.5 Ma. The excellent preservation of fish skeletal remains seems to be primarily related to the development of a microbial film that promoted the rapid mineralization of bones and other organic components. Slightly less than thousand fish specimens (sharks, batoids and teleosts) have been analyzed, among which 49 taxa belonging to 37 families have been identified. The round herring Spratelloides sp., the lanternfish Diaphus sp. and the scorpionfish Scorpaena prior sharply dominate the assemblage, represented by more than 50% of the recognized specimens. The comparative analysis of the ecological categories indicates that the assemblage primarily consists of benthic and demersal neritic (e.g., Boops aff. roulei, Callionymus sp., Calotomus priesli, Chaetodon cf. ficheuri, Coris sigismundi, “Ctenolabrus” agassizi, Dentex sp., Epinephelus cf. casottii, Gaidropsarus pilleri, Lophius sp., Malacanthus sp., Miobothus weissi, Mullus sp., Nerophis zapfei, Palimphemus anceps, Priacanthus cf. croaticus, Scorpaena prior, Synodus sp., Trachinus sp.) and coastal epipelagic taxa (e.g., Belone sp., Sardinella sp., Scomber sp., Sphyraena sp., Spratelloides sp., Trachurus sp.), with a relatively diverse contingent of migratory pelagic and oceanic taxa (Bregmaceros cf. albyi, Cetorhinus parvus, Diaphus sp., Merluccius aff. errans) The paleoecological analysis of the fish assemblage suggests that the deposition of the finely laminated fossiliferous calcarenitic marls occurred not far from the coastline in a moderately shallow basin surrounded by rocky reefs and seagrass beds and remarkably influenced by the open sea. The highly heterogeneous composition of the assemblage, which is characterized by the co-occurrence of coastal, and opportunistic mesopelagic taxa, is consistent with the unstable eutrophic conditions indicated by the nearly monospecific or oligospecific blooms of Coccolithus pelagicus and reticulofenestrids that triggered the periodic hypoxic events. From a paleobiogeographical point of view, the fish assemblage from St. Margarethen exhibits a clear Atlantic-Mediterranean configuration, but also includes several taxa today restricted to the tropical waters of the Indo-Pacific and Caribbean regions (e.g., Aeoliscus, Calotomus, Chaetodon, Malacanthus, Pristis), representing the heredity of the Tethyan biota.
The Badenian Fish Fauna of St. Margarethen, Eisenstadt-Sopron Basin, Burgenland, Central Paratethys: Stratigraphy, Paleoecology and Paleobiogeography
CARNEVALE, Giorgio;
2013-01-01
Abstract
Exquisitely preserved articulated skeletal remains of teleost fishes from the Badenian corallinacean limestone exposed in the Eisenstadt-Sopron Basin, Austria are known since the first part of the XIX century thanks to the efforts of brilliant Austrian naturalists such as Johann Jakob Heckel and Rudolf Kner that described several specimens collected in a few outcrops located in the nearby of the village of St. Margarethen. A vast collection of extraordinarily well preserved fishes and invertebrates from the corallinacean limestone was recently accumulated during two large excavation campaigns carried out in the Kummer Quarry, about 2 km E of St. Margarethen village (47°48’01.76’’N, 16°37’59.12’’E). These fossils, primarily represented by skeletal remains of teleost fishes and subordinately by shark teeth, crustaceans, bryozoans, echinoids, molluscs and brachiopods, are preserved in finely laminated greenish-whitish calcarenitic marls that apparently originated in low-energy depressions of the floor surrounded by carbonate sand build-ups. The mass accumulations of fishes and the thanatocoenoses of authochthonous benthic invertebrates originated in response to repeated hypoxic events. The repeated and severe benthic hypoxic events were probably associated to blooms of Coccolithus pelagicus and some reticulofenestrids triggered by periodic increased input of nutrients. The Late Badenian age of this konservat-lagerstätte has been estimated based on calcareous nannoplankton, which indicates zone NN5b, around the Langhian/Serravallian boundary, roughly between 14.0 and 13.5 Ma. The excellent preservation of fish skeletal remains seems to be primarily related to the development of a microbial film that promoted the rapid mineralization of bones and other organic components. Slightly less than thousand fish specimens (sharks, batoids and teleosts) have been analyzed, among which 49 taxa belonging to 37 families have been identified. The round herring Spratelloides sp., the lanternfish Diaphus sp. and the scorpionfish Scorpaena prior sharply dominate the assemblage, represented by more than 50% of the recognized specimens. The comparative analysis of the ecological categories indicates that the assemblage primarily consists of benthic and demersal neritic (e.g., Boops aff. roulei, Callionymus sp., Calotomus priesli, Chaetodon cf. ficheuri, Coris sigismundi, “Ctenolabrus” agassizi, Dentex sp., Epinephelus cf. casottii, Gaidropsarus pilleri, Lophius sp., Malacanthus sp., Miobothus weissi, Mullus sp., Nerophis zapfei, Palimphemus anceps, Priacanthus cf. croaticus, Scorpaena prior, Synodus sp., Trachinus sp.) and coastal epipelagic taxa (e.g., Belone sp., Sardinella sp., Scomber sp., Sphyraena sp., Spratelloides sp., Trachurus sp.), with a relatively diverse contingent of migratory pelagic and oceanic taxa (Bregmaceros cf. albyi, Cetorhinus parvus, Diaphus sp., Merluccius aff. errans) The paleoecological analysis of the fish assemblage suggests that the deposition of the finely laminated fossiliferous calcarenitic marls occurred not far from the coastline in a moderately shallow basin surrounded by rocky reefs and seagrass beds and remarkably influenced by the open sea. The highly heterogeneous composition of the assemblage, which is characterized by the co-occurrence of coastal, and opportunistic mesopelagic taxa, is consistent with the unstable eutrophic conditions indicated by the nearly monospecific or oligospecific blooms of Coccolithus pelagicus and reticulofenestrids that triggered the periodic hypoxic events. From a paleobiogeographical point of view, the fish assemblage from St. Margarethen exhibits a clear Atlantic-Mediterranean configuration, but also includes several taxa today restricted to the tropical waters of the Indo-Pacific and Caribbean regions (e.g., Aeoliscus, Calotomus, Chaetodon, Malacanthus, Pristis), representing the heredity of the Tethyan biota.
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