The Latest Succession of Dinosaur Tracksites in Europe: Hadrosaur Ichnology, Track Production and Palaeoenvironments

Bernat Vila,Oriol Oms,Violeta Riera,José Ignacio Canudo,Víctor Fondevilla,Àngel Galobart,Rodrigo Gaete,Richard J Butler

doi:10.1371/journal.pone.0072579

Abstract

A comprehensive review and study of the rich dinosaur track record of the Tremp Formation in the southern Pyrenees of Spain (Southwestern Europe) shows a unique succession of footprint localities prior to the end-Cretaceous mass extinction event. A description of some 30 new tracksites and data on sedimentary environments, track occurrence and preservation, ichnology and chronostratigraphy are provided. These new track localities represent various facies types within a diverse set of fluvial environments. The footprint discoveries mostly represent hadrosaurian and, less abundantly, to sauropod dinosaurs. The hadrosaur tracks are significantly smaller in size than, but morphologically similar to, those of North America and Asia and are attributable to the ichnogenus Hadrosauropodus. The track succession, with more than 40 distinct track levels, indicates that hadrosaur footprints in the Ibero-Armorican region occur predominantly in the late Maaastrichtian (at least above the early Maastrichtian–late Maastrichtian boundary). The highest abundance is found noticeably found in the late Maastrichtian, with tracks occurring in the C29r magnetochron, within about the latest 300,000 years of the Cretaceous.

Highlights

The end-Cretaceous mass extinction was one of the major events in the history of life on Earth, resulting in the demise of multiple taxa [1]
The aim of the present paper is to provide the first comprehensive review and update of the latest Cretaceous dinosaur track record in Europe with the inclusion of 28 new localities, and to discuss their implications in terms of ichnotaxonomy, palaeoenvironments, chronostratigraphy, and the K–Pg boundary extinction event
The following descriptions refer to the 28 newly discovered localities (Table 1), some of which have been briefly referred by previous authors [6,21,37,46], and to two already known sites (La Mata del Viuda, Areny 1; [17,19])

Summary

Introduction

The end-Cretaceous mass extinction was one of the major events in the history of life on Earth, resulting in the demise of multiple taxa [1]. Much of the current knowledge is from the fossil bone record recovered from the uppermost levels of many geologic formations around the world. The discovery of dinosaur tracks close to the Cretaceous–Palaeogene (K–Pg) boundary has shown their utility as chronostratigraphical markers [8]. The autochthonous character of fossil tracks means that they provide unmistakable proof of the presence of the track maker in a restricted temporal and spatial context, with no possibilities of reworking as is possible for bone remains. Tracks represent a valuable tool for analysing last occurrences and diversity patterns of dinosaurs before the K–Pg extinction event

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Conclusion