The late Permian time was a transformative period before the most severe mass extinction known. Even though fishes constitute a key component of marine ecosystems since the Silurian, their biogeographic patterns during the late Permian are currently insufficiently known. The new ichthyofaunal material described here comes from the southeastern part of the Zechstein Basin, from the calcareous storm sediments alternating with marls, which were deposited in less energetic conditions. Chondrichthyans and osteichthyans are reported here for the first time from the Nowy Kościół quarry in the SW Poland. The assemblage consists of various euselachian dermal denticles, actinopterygian scales and teeth, and isolated hybodontoid tooth putatively assigned as extremely rare ?Gansuselache sp. from the Permian. The diverse actinopterygian tooth shapes show significant ecological differentiation of fishes exploring sclerophagous, durophagous, and herbivory modes of feeding in the given part of the Zechstein Basin suggesting the presence of complex ecosystems even in hyper-saline conditions of an epicontinental sea.
The late Permian was a transformative time, which ended with one of the most significant extinction events in Earth's history. Fish assemblages are a major component of marine food webs. The macroevolution and biogeographic patterns of late Permian fish are currently insufficiently known. In this contribution, a late Permian ichthyofauna from the Kūmas quarry (southern Latvia) is described for the first time. The studied late Permian Latvian assemblage consisted of isolated chondrichthyan teeth putatively associated to ? Helodus sp., ?Acrodus sp., ? Omanoselache sp. and euselachian-type dermal denticles as well as many actinopterygian scales, numerous teeth and multiple unidentifiable microremains. This ichthyofaunal assemblage is very similar to the contemporaneous Lopingian complex of the Naujoji Akmenė formation from the Karpėnai quarry (northern Lithuania), despite the fact that the Kūmas assemblage is more diverse and abundant, in terms of fossil remains. The differences in the abundance of microremains could possibly be explained by a fresh water influx into the north-eastern Zechstein Basin margin, which probably reduced the salinity of the sea water. The new data enable a better understanding of the poorly known late Permian fish diversity from the north-eastern part of the basin.
Keywords Microremains • Chondrichthyans • Actinopterygians • Histology • Permian • Baltic
ResumenEl Pérmico superior fue un periodo transformador, que terminó con una de las extinciones más masivas de la historia de la Tierra. Los peces son un componente importante de las redes tróficas marinas. Los patrones macroevolutivos y biogeográficos de los peces del Pérmico superior han sido escasamente estudiados. En este trabajo describimos por primera vez la ictiofauna de la cantera de Kūmas (sur de Letonia). La asociación estudiada consiste en dientes de condrictios aislados asociados a ?Helodus sp., ? Acrodus sp., ? Omanoselache sp.; escamas de tipo Euselachii y de actinopterigios; numerosos dientes y otros microrestos no identificables. La asociación de ictiofauna descrita es muy similar a la actual del complejo
Permian fishes and their isolated microremains are known from many localities in the Zechstein Basin. However, up to date the vertebrates have never been revealed in the southeasternmost part of this ancient sea. The new material consists of euselachian-type dermal denticles,?Listracanthus sp. dermal denticle,?Omanoselache sp. tooth, actinopterygian scales and actinopterygian teeth. Here, the detailed study of euselachian and actinopterygian remains, their stratigraphic distribution and geographical contexts is presented. Based on the qualitative analysis of teeth shapes several ecomorphotypes were described as well as the probable dietary preferences of fishes were reconstructed. These finds confirmed existence of small predators who fed on soft bodied prey as well as durophagous forms which were feeding on small shelly crustaceans or molluscs. The analysis of stratigraphic distribution of microremains, and their comparison with neighbouring sections revealed a spatially correlatable trend in increasing abundance of fishes in the more clayey parts of sections, interpreted to be positively associated with a sea level transgression event.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.