Fish remains from the Rhaetian (Late Triassic) of Winterswijk, the Netherlands (Pisces: Chondrichthyes and Actinopterygii)

Abstract

Chondrichthyan and actinopterygian fish remains from Rhaetian (c. 208.05-201.36 Ma) or perhaps Late Norian deposits in the Winterswijk quarry are described. The most abundant taxon is the actinopterygian Gyrolepis albertii, followed by the chondrichthyan Lissodus minimus. Furthermore, the palaeopterygian actinopterygians Saurichthys longidens and Birgeria acuminata, and some teeth of neopterygians Sargodon tomicus, 'Lepidotes' sp. and indeterminate pycnodontiforms are recorded in addition to the chondrichthyans Rhomphaiodon minor, Parascylloides turnerae and some 'Hybodus' cf. cuspidatus (senior synonym of H. cloacinus). Chondrichthyan dermal denticles, actinopterygian scales and gill rakers, tooth plates, and some fish bones were also found. There is considerable faunal resemblance to the various localities from the Rhaetian of the British Penarth Group, although it depends on the location as to whether chondrichthyans or actinopterygians prevail in the samples. On average, there are more chondrichthyan teeth present in the British samples than actinopterygian teeth, which is opposite to the situation in Winterswijk. That might be explained by different ecological circumstances, such as lower oxygen levels in bottom waters in Winterswijk and freshwater input and/or changes in salinity in the UK.