Holwerda-2025-Mosasaur-feeding-ecology-A - Preliminary Multi-Proxy Approach

Aug 28, 2026

Mosasaur taxa recovered from the Bearpaw Formation of Alberta, Canada, show exceptional preservation following rapid burial, enabling dietary and habitat interpretations. With a community dominated by Mosasaurus missourensis and Prognathodon overtoni plus several less common taxa, the study tests niche partitioning using multiple independent proxies. Two-dimensional dental microwear quantifies tooth abrasion, skull tooth rows and isolated teeth are compared, tooth bending strength assesses biomechanical stress per taxon, and EDX trace elements provide a preliminary trophic-level signal. Where stomach contents are preserved, diet is directly confirmed. The combined results distinguish dietary niche differentiation among mosasaurs and support future chemical or analytical palaeoecological work.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

Introduction

Study background and setting

Motivation for niche partitioning

Materials and Methods

Two-dimensional microwear analysis

Tooth bending strength measurements

Energydispersive X-ray spectroscopy (EDX)

Stomach content evidence

Article Mosasaur Feeding Ecology from the Campanian Bearpaw Formation, Alberta, Canada: A Preliminary Multi-Proxy Approach Femke M. Holwerda 1,2, *, Mark T. Mitchell 1, Madelon van de Kerk 3 and Anne S. Schulp 2,4 Academic Editors: Michael Wink and Nathalie Bardet Received: 29 December 2024 Revised: 2 March 2025 Accepted: 6 March 2025 Published: 13 March 2025 Citation: Holwerda, F.M.; Mitchell, M.T.; van de Kerk, M.; Schulp, A.S. Mosasaur Feeding Ecology from the Campanian Bearpaw Formation, Alberta, Canada: A Preliminary Multi-Proxy Approach. Diversity 2025, 17, 205. [https://doi.org/](https://doi.org/)[ ](https://doi.org/)[10.3390/d17030205](10.3390/d17030205) Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([https://creativecommons.org/](https://creativecommons.org/)[ ](https://creativecommons.org/)[licenses/by/4.0/](licenses/by/4.0/)) . 1 Royal Tyrrell Museum of Palaeontology, P.O. Box 7500, Drumheller, AB T0J 0Y0, Canada 2 Department of Geosciences, Utrecht University, Princetonlaan 8a, 3584 CB Utrecht, The Netherlands; [a.s.schulp@uu.nl](a.s.schulp@uu.nl) 3 School of Environment & Sustainability, Western Colorado University, 1 Western Way, Gunnison, CO 81231, USA; [mvandekerk@western.edu](mvandekerk@western.edu) 4 Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands * Correspondence: [f.m.holwerda@uu.nl](f.m.holwerda@uu.nl) Abstract: Mosasaur taxa recovered from the Bearpaw Formation, Alberta, Canada, generally show exceptional preservation after rapid burial. Since the mosasaur community consisted of two dominant taxa, Mosasaurus missourensis Prognathodon overtoni, and three less prevalent taxa Tylosaurus proriger, Mosasaurus conodon, and Plioplatecarpus primaevus, some form of habitat or dietary niche partitioning is to be expected. To test this, several approaches are tried. Two-dimensional microwear analysis is used as an exploratory method to quantify tooth abrasion by food items. The good preservation of skull material reveals complete tooth rows of the upper and lower jaws for Mosasaurus missouriensis and Prognathodon overtoni, as well as isolated teeth for all taxa. The teeth are also measured for tooth bending strength to test stress regarding usage of teeth per taxon. Energydispersive X-ray spectroscopy (EDX) measurements show trace elements which may be a preliminary test for relative trophic level positioning. Some mosasaurs have their stomach contents preserved, providing direct and unambiguous evidence of diet. The results showa relatively clear separation of two-dimensional microwear counts between Mosasaurus, Prognathodon, and Plioplatecarpus, which, to some extent, is reflected in the EDX analyses, too. Tooth bending strength measurements show a clear difference between the latter three mosasaurs but no difference between the lower and upper jaws in Mosasaurus or Prognathodon. The combination of these three techniques maps a clear dietary niche differentiation of Bearpaw mosasaurs, which lays the groundwork for future analytical or chemical palaeoecological studies. Keywords: Mosasauridae; Bearpaw Formation; dental microwear; feeding ecology; Cretaceous; geochemical analysis 1. Introduction The Campanian Bearpaw Formation of Southern Alberta, Canada, represents one of the northernmost extensions of the Western Interior Seaway [1,2] . In Southern Alberta, it consists of marine shale with nodular concretions [3] . Ammolite mining, a precious stone derived from fossilized ammonites [4,5] at the city of Lethbridge, as well as other excavations, have yielded a considerable amount of vertebrate and invertebrate marine fossils, representing a Campanian marine ecosystem (74.1 Ma) with average bathymetry of ~40 m (MM pers. obs.) Prominently and consistently present are mosasaurs (Reptilia: Squamat

FAQs

What proxies are used to study mosasaur feeding ecology in the Bearpaw Formation?

The study combines two-dimensional dental microwear, tooth bending strength measurements, energydispersive X-ray spectroscopy (EDX) for trace-element signals, and direct evidence from preserved stomach contents where available.

Why is niche partitioning expected among Bearpaw mosasaurs?

The mosasaur community includes two dominant taxa plus several less common taxa, so differences in habitat or dietary niche use are expected to reduce competition.

What do the results indicate about dietary niche differentiation?

Two-dimensional microwear counts separate Mosasaurus, Prognathodon, and Plioplatecarpus, and this separation is partly reflected in the EDX analyses. Tooth bending strength further differentiates among taxa, collectively supporting dietary niche differentiation within the Bearpaw mosasaur assemblage.

Aug 28, 2026

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