Upper Jurassic tidal flat megatracksites of Germany—coastal dinosaur migration highways between European islands, and a review of the dinosaur footprints

Abstract

Dinosaur tracks occur at three vertebrate tracksites in north-western Germany, in the acanthicum/mutabilis ammonoid biozone of the basal Upper Kimmeridgian (Upper Jurassic,. The trackbeds are mud-cracked, siliciclastic, tidal sand flat biolaminates, overlain by paleosol beds. Channels contain rare fossils of sauropod, ornithopod and pterosaur bones as well as shark and plant remains. Large sauropod tracks of the Elephantopoides type, which have been found in an intertidal megatracksite environment to the north of the Rhenish Massif, are reviewed herein, together with a camptosaurid track type (?Iguanodontipus), the theropod track Megalosauropus and possible dryosaurid Grallator tracks. These large dinosaur tracks have been reviewed and compared to all other known European localities. At the Barkhausen tracksite with its important ichnoholotypes, trackways of a possible sauropod herd consisting of ten small to mediumsized individuals and one large individual have been exposed, revealing different speeds of travel as well as important social behaviour in these large herbivorous dinosaurs. Two theropods also left their imprints on the same track horizon, one travelling towards the south in a direction contrary to the movement of the herd, and the second travelling towards the north-west, cutting across the other trackways. Five different types of Upper Jurassic dinosaur tracks have now been recorded from coastal environments scattered around Europe, with the best footprint records forming extensive megatracksites in biolaminates between Jurassic islands in central Europe. These intertidal flats formed periodic bridges between the islands, allowing dinosaur interchanges and migrations between America and Eurasia, which may help to explain the much broader palaeobiogeographic distributions of dinosaur species during the Late Jurassic.

Dinosaur tracks from the Langenberg Quarry (Late Jurassic, Germany) reconstructed with historical photogrammetry: Evidence for large theropods soon after insular dwarfism

“…Described in 1974 by Kaever and Lapparent, it includes tracks of large tridactyl dinosaurs (ascribed to theropods) and the first sauropod footprints discovered in Europe (Le Loeuff et al, 2006). The two tridactyl trackways are of approximately the same size (Lockley and Meyer, 2000;Kaever and Lapparent, 1974;Diedrich, 2011b). The footprints measure 63 cm in length (Lockley and Meyer, 2000) and thus are larger than the footprints from the Langenberg quarry.…”

“…Despite large areas of exposures of Late Jurassic sediments, dinosaur tracks from this period remain rare in Germany. All three previously published tracksites are located in the Wiehen Mountains, including the famous Barkhausen tracksite which has been known since 1921 (Kaever and de Lapparent, 1974) as well as two quarries that have produced isolated footprintbearing slabs (Diedrich, 2011b).…”

Marine vertebrates from the Santonian coastal carbonates ofnorthwestern Germany – a tool for the reconstruction of a Proto-North Sea Basin intertidal dinosaur-exchange bridge

“…The idea of dinosaurs using beaches and intertidal areas as possible seasonal migration zones is becoming more favoured, with many new discoveries of dinosaur tracks recorded in European Middle Triassic [60,61] or Upper Jurassic [62] coastal or intertidal beach deposits, and examples such as recently described CenomanianTuronian trackways on the Adriatic Carbonate Platform and in central Europe [63]. Only such intertidal 'bridges' can explain the distribution of Santonian dinosaur records along European Cretaceous islands or peninsula coasts.…”

A walk in the maze: Variation in Late Jurassic tridactyl dinosaur tracks - A case study from the Late Jurassic of the Swiss Jura Mountains (NW Switzerland)

“…Besides the tracks from the Combe Ronde tracksite tentatively assigned to Carmelopodus by Marty (2008), the main small to medium-sized tridactyl tracks identified have been from Spain (Grallator and Anomoepus, from several sites in Asturias, Lockley et al, 2008;Piñuela, 2015;Castanera, Piñuela & García-Ramos, 2016), France (Carmelopodus, Loulle tracksite, Mazin, Hantzpergue & Pouech, 2016), Poland (Wildeichnus, cf. Jialingpus and Dineichnus, different units in the Holy Cross Mountains, , Germany (Grallator, Bergkirchen tracksite, Diedrich, 2011) and Portugal (Dineichnus and ?Therangospodus, Lockley et al, 1998a;46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Lockley, Meyer & Moratalla, 2000). Other significant Late Jurassic areas with minute to medium-sized tridactyl dinosaur tracks are found in the USA (Foster & Lockley, 2006), Morocco (Belvedere, Mietto & Ishigaki, 2010), China (Xing, Harris & Gierliński, 2011;Xing et al, 2016), Yemen (Schulp & Al-Wosabi, 2012) and Turkmenistan (Lockley, Meyer & Santos, 2000;Fanti et al, 2013).…”