Original paper
Early Oxfordian occurrence of shark Notidanoides muensteri in Jurassic shelf lagoon deposits at Brno-Hády (Czechia)
Hykš, Petr; Kumpan, Tomáš; Svobodová, Andrea
Palaeontographica Abteilung A (2023)
56 references
published online: Jul 27, 2023
manuscript accepted: Jun 29, 2023
manuscript received: Oct 30, 2022
Abstract
Notidanoides muensteri (Agassiz, 1843) is an extinct species of hexanchiform sharks, a typical element of Late Jurassic environments on the northern shelf of the Tethys Ocean. It is the only valid representative of genus Notidanoides. Isolated teeth and even articulated skeletons of this species were found in several European localities, mainly in Germany and mostly in an interval from the middle Oxfordian up to the lower Tithonian. This study presents a new collection of lower Oxfordian teeth of N. muensteri from a classical locality of the Moravian Jurassic shelf lagoon facies at Brno-Hády (Czechia). We also provide biostratigraphic re-assessment of this important study section, formerly considered as middle Oxfordian. The lower Oxfordian position of the studied specimens was determined by ammonite and nannoplankton biostratigraphy and corresponds to the Cordatum ammonite Zone. This zone is well-documented by Boreal immigrant taxa, such as ammonite Cardioceras (C.) cordatum and nannoplankton Stephanolithion bigotii maximum. The studied specimens are the only fossil remains of N. muensteri known from this ammonite zone worldwide. The stratigraphic range of this species is extended based on teeth reported from France and Poland, and its first appearance is assigned to the Callovian/Oxfordian boundary. The paleobiogeographic distribution of N. muensteri indicates that this shark preferred shelf lagoon environments associated with nearby carbonate build-ups and islands. Its poor representation in neritic deposits could be a result of the relative fragility of its teeth.
Keywords
Upper Jurassic • Hexanchiformes • Ammonites • nannoplankton • biostratigraphy