Carbon isotope trends in north-west European mosasaurs (Squamata; Late Cretaceous)

Tom J Giltaij,John W.M Jagt,Van Der Lubbe Jeroen,Bent Lindow,Anne S Schulp

doi:10.37570/bgsd-2021-69-04

Abstract

The carbon stable isotope composition (δ13C) of tooth enamel in mosasaurid squa-mates reflects aspects of their diet and diving behaviour. Here we present new δ13C data for such marine squamates from the Maastrichtian of Denmark and compare these with results obtained in previous studies from the lower-latitude type area of the Maastrichtian Stage (latest Cretaceous; 72.1–66.0 Ma) in the south-east Nether-lands and north-east Belgium. For the Danish samples, there is a weak correlation between mosasaur body size and δ13C values, with larger-sized taxa having lower δ13C values, comparable to what has previously been observed for mosasaurs from the Maastrichtian type area.

Highlights

Trilobites dominantly of middle Cambrian (Miaolingian Series, Wuliuan Stage) age are described from the Telt Bugt Formation of Daugaard-Jensen Land, western North Greenland (Laurentia), which is a correlative of the Cape Wood Formation of Inglefield Land and Ellesmere Island, Nunavut
In specimens of Kootenia cf. erromena from the Telt Bugt Formation, the maximum transverse width of the pygidial axis is greater than each pleural area whereas it is narrower in species described by Poulsen (1927) and V
Specimens of Kootenia cf. erromena from Geologiske Undersøgelse (GGU) sample 212805 are otherwise similar to K. resseri in that the pygidium usually has six pairs of spines, an axis with three rings and long tail piece, and a well-developed border; cranidia of K. resseri were not described by Poulsen (1927) nor by V

Summary

Methods

Specimens were coated with black colloidal carbon and whitened with ammonium chloride sublimate prior to photography using a Lumenera Infinity X32 digital camera and MicroNikkor 55 mm lens. GGU sample 206303 was collected by J.S. Peel on 15th July 1976 from 30 m above the base of the Telt Bugt Formation, which is about 100 m thick . GGU samples 206307–206309 were collected from the Romer Søer area (80°03’N, 60°41’W; Fig. 2) by J.S. Peel on 16th July 1976 from 2 m, 10 m and 40 m, respectively, above the base of the Telt Bugt Formation, of which about 70 m are exposed (Fig. 5). GGU samples 212805–212814 and GGU 212873 were collected by J.S. Peel on 6th–18th July 1975 from the type section of the Telt Bugt Formation (Fig. 1a, locality 5; Figs 2, 5), north-east of Telt Bugt, Daugaard-Jensen Land (79°56.3’N, 60°15’W).

Discussion

Findings