A Rhaetian microvertebrate fauna from Stowey Quarry, Somerset, U.K.

Abstract

Rhaetian bone beds have been described from many locations in south-west England, around Bristol. One site that has never been reported is Stowey Quarry, some 13 km south of Bristol. This quarry yielded Lias, and revealed thin Rhaetian units in the quarry floor, including two bone beds, the basal Rhaetian bone bed, and a second, higher bone bed, also within the Westbury Formation. The fossil fauna of both includes elements typical of Rhaetian bone beds elsewhere, but showing differences in faunal composition between the two. The basal bone bed yielded more specimens and more species, with three taxa (Sargodon tomicus,Rhomphaiodon minor and Hybodus cloacinus) exclusive to this bed and eleven identified in total. Severnichthys acuminatus accounts for more than 50% of the countable teeth from the basal bone bed, followed by Gyrolepis albertii with 20%, Lissodus minimus with 14% and Rhomphaiodon minor with 9%. The basal bone bed, as ever, is dominated by chondrichthyans, whereas the upper bone bed is dominated by osteichthyans, which form 90% of the non-dental remains. The only unique taxon is Dapedium, and Gyrolepis albertii is the most abundant species with 45% of countable teeth, followed by Severnichthys acuminatus with 38% and Duffinselache holwellensis with 11%. These faunal differences, and the equally good condition of specimens between both samples confirms that the upper bone bed is independent of the basal bone bed, and is not a reworked subsample.

Note on the Rhaetian fish fauna from a subrosion pipe in Winterswijk (the Netherlands), with a discussion on the validity of the genus Severnichthys Storrs, 1994

“…We therefore based our identifications on comparison with material described in the above-mentioned literature. Comparison of our fauna with that from other European Rhaetian localities, especially those of the British Penarth Group (Korneisel et al, 2015;Lakin et al 2016;Slater et al, 2016;Cavicchini et al, 2018;Cross et al, 2018) shows an overall resemblance in faunal composition, with the shark genera Lissodus and Rhomphaiodon, and the actinopterygians Gyrolepis, Saurichthys and Birgeria (the latter two often jointly referred to as Severnichthys) as the most abundant elements. See Table 1 for an overview.…”

First record of Mesozoic scroll coprolites: classification, characteristics, elemental composition and probable producers

“…27A–E) and Rhaetian Stowey Quarry, UK (Cavicchini et al . , p. 154, fig. 8) and lustre on the dorsal surface (Fig.…”

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

“…This species has also been mentioned from the UK (Duffin, 1985(Duffin, , 1998aCuny & Risnes, 2005;Foffa et al, 2014;Allard et al, 2015;Nordén et al, 2015;Korneisel et al, 2015;Slater et al, 2016;Whiteside et al, 2016;Lakin et al, 2016;Whiteside & Duffin, 2017;Landon et al, 2017;Cavicchini et al, 2018;Cross et al, 2018;Ronan et al, 2020;Moreau et al, 2021;Williams et al, 2022), Eastern Europe (Chrząstek, 2008;Michalík et al, 2013;Ősi et al, 2013;Posmoşanu, 2015;Botfalvai et al, 2019;Szabó et al, 2019) and Western Europe (Duffin, 1993;Duffin & Delsate, 1993;Cuny, 1995;Godefroit et al, 1998;Henz & Hertel, 2011;Cuny et al, 2013;Sander et al, 2016;Diependaal & Reumer, 2021).…”

“…The height of these scales is about 1 mm. This type of scale is mentioned from many localities of the British Penarth Group (e.g., Duffin, 1998a;Landon et al, 2017;Cavicchini et al, 2018;Ronan et al, 2020;Moreau et al, 2021;Williams et al, 2022) and also from Poland (Duffin & Gaździcki, 1977) and Luxemburg (Delsate & Duffin, 1999).…”