A probable thyreophoran (D1inosauria, Ornithischia) footprint from the Upper Triassic of southernSweden

}ESPER MILAN & GERARD GIERLINSKI

Milan, J. & Gierlinski, G. 2004-10-22: A probable thyreophoran (Dinosauria, Omithischia) foot­ print from the Upper Triassic of scmthern Sweden. Bulletin of the Geological Society of Denmark, Vol. 51, pp. 71-75, Copenhagen.© 2004 by the Geological Society of Denmark. ISSN 0011--6297. https://doi.org/10.37570/bgsd-2004-51-05

A curious blunt-toed tridactyl footprint of a relatively large trackmaker is stored in the Geological Museum in Copenhagen. The footJprint was found nearly 50 years ago in the Rhaetian coal-bearing strata mined in the Gustav Adolf fvline, near Hoganas, Scania, Southern Sweden. The morphology of the specimen suggests that it was left by an early advanced thyreophoran dinosaur, in this case the earliest known.

Kei;-words: FootJprint,T hyreophoran dinosaur, Late Triassic, Scania, Sweden.

Jesper Milan [[email protected]], Geological Institute, 0stervoldgade 10, 1350 Copenhagen K, Denmark. Gerard Gierlinski [[email protected]], Polish Geological Institute, ul. Rakowiecka 4, 00-975 Warsz:awa, Po­ land. 16 June 2004.

Dinosaur footprints from the Upper Triassic, Rhae­ tian, Hoga.nas Formation, in southern Sweden were first reported by Bolau (1952), who described them as theropod footprints without assigning them to any ichnotaxon. Other tracks, also of theropod origin,were found in the Early Jurassic strata of Helsingborg and Vallakra (Pleijel 1975; Ahlberg & Siverson 1991). Gierlinsk:i & Ahlberg (1994) assigned Late Triassic tracks from southern Sweden to the ichnotaxon Grallator (Eubrontes) giganteus Hitchcock, 1845, and the Lower Jurassic tracks to Grallator (Eubrontes) soltyko­ vensis Gierlinsk:i,1991 following subichnogeneric des­ ignation proposed by Olsen and Gatton (1984). Re­ cently, these ichnotaxa have been revised as Eubrontes giganteus and Kayentapus soltykovensis (see Gierlinsk:i 1996; Olsen et al. 1998). All tracks so far described from the Hoganas Formation have been clearly of theropod origin, characterized by a functionally tridactyl pes, the third digit being the longest, and having relatively narrow claws (Fig. 1). However, the specimen exhib­ ited on display at the Geological Museum in Copen­ hagen (MGUH 27219) (Fig. 2), differs from all other Early Mesozoic tracks hitherto described from south­ em Sweden. The track was found in the roof of the Fig. 1. Typical theropod track, Grallator (Eubrontes) giganteus Gustav Adolf coal mine, Hoganas, between 1950 and from the Gustaf Adolf coal mine in Hoganas, southern Swe­ 1955 and was purcl1ased by the Geological Museum den. Notice the long slender digit impressions and the sharp in Copenhagen from a relative to one of the workers laterally compressed claw imprints. Scalebar 5 cm. Figure from the mine. Vertebrate tracks are often found in modified after Gierlinski & Ahlberg 1994.

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