Dinosaur tracks from the Lower Cretaceous of Regumiel de la Sierra (province of Burgos, Spain): Inferences on a new quadrupedal ornithopod trackway

Manus Track Preservation Bias as a Key Factor for Assessing Trackmaker Identity and Quadrupedalism in Basal Ornithopods

“…While some of these characters are typical of theropod trackmakers, the presence and the oval morphology of manus tracks, on the other hand, supports an ornithopod origin. Furthermore, the inward rotation of pes tracks, the round heel pad and relatively short steps are typical features of ornithopod rather than theropod trackmakers [19], [20], [21], [22], [23], [40].…”

“…Considering ornithopod locomotion, trackways of small–medium sized quadrupedal ornithopods are interesting because the majority of such trackways are much larger and often attributed to iguanodontids and hadrosaurs [19], [20], [21], [29]. The derived ornithopods such as hadrosaurs are considered predominantly quadrupedal while more basal forms such as “hypsilophodontids” are considered bipedal [66], [67].…”

“…Several authors have previously attempted to use multivariate analysis to discriminate between theropod and ornithopod tracks [10], [11], [12], but ultimately these analyses are based upon variations of the above parameters, all of which may be subject to considerable variation depending on factors implicit in both track formation and preservation [8], [13], [14], [15], [16], [17], [18]. Nonetheless, the occurrence of manus tracks associated with pes tracks and forming a well-defined trackway pattern seems to be unequivocal evidence in favour of an ornithopod instead of a theropod affinity [19], [20], [21], [22], [23].…”

“…Well-preserved trackways of quadrupedal ornithopods (with complete pes-manus sequences) have been reported in several localities throughout the Cretaceous, being more abundant in post-Berriasian ([19], [20], [21], [22] and references therein). During the last decade, sites from the latest Jurassic–earliest Cretaceous (Tithonian–Berriasian) interval have also been reported in Europe that preserve quadrupedal ornithopod trackways [27], [28], [29], [30], [31], [32].…”

The ichnological record of Australian Cretaceous ornithopodan dinosaurs: diversity, behaviour, and implications for the evolution of pedal posture

“…A goal within the study of ichnology is to determine the identity of the trace-maker. Trace fossils in the form of tracks produced by tetrapods can provide a wealth of information about the trackmaker including pedal morphology (Thulborn, 1990;Irby 1995;, body posture (Moratalla et al, 1994;Gierliński, 1994;Wilson and Carrano, 1999;Milner et al, 2009), locomotor ability (Alexander, 1976;Thulborn and Wade, 1989;Moratalla et al, 1994;Gatesy et al, 1999;Mazzetta and Blanco, 2001;Day et al, 2002;Dalman, 2006;Ezquerra et al, 2007), sociality (Lockley and Matsukawa, 1999;Barco et al, 2006;, preferential environments (Lockley, 1991) as well as stratigraphic and geographic faunal occurence (Matsukawa et al, 2005;Melchor et al, 2002;Moreno and Benton, 2005;Paik et al, 2006;Mateus and Milan, 2008). The morphology of dinosaur tracks usually reflects characteristics of the trackmaker's pedal skeleton (toe number and symmetry, pedal posture; Lockley, 1991;Carrano and Wilson, 2001), and so identifying the tracks made by dinosaurs such as sauropods, stegosaurs and ceratopsians can be done relatively easily.…”