First report of lizard trackways from the Jurassic of Europe

Two well-preserved lizard trackways from the Kimmeridgian Lastres Formation of Asturias (northern Spain) are described. Trackway 1 (T1) consists of seven tracks (four manus and three pes), whereas Trackway 2 (T2) includes six tracks (three manus and three pes). The estimated body lengths of the T1 and T2 trackmakers are slightly below 50 cm and 30 cm, respectively. Both trackways, preserved as natural casts, show asymmetric and ectaxonic manus and pes prints, ranging from tetradactyl to pentadactyl. Digit lengths follow the pattern IV > III > II, with digit V, when present, similar to or slightly longer than digit I. Distinct claw marks are preserved on most digit impressions, particularly in T1. Lizard footprints are uncommon in the Jurassic, and the Upper Jurassic records are especially rare. These new trackways represent the only well-documented lizard trackways from the Upper Jurassic. They are attributed to Rhynchosauroides and constitute the latest occurrence of this ichnogenus in the global record. Experimental comparisons with modern lizards suggest that the tail placement and footprints arrangement in T1 may provide clues to gait and movement patterns in these fossil trackmakers.