Speeds and stance of titanosaur sauropods: analysis of Titanopodus tracks from the Late Cretaceous of Mendoza, Argentina

Abstract

Speed estimations from trackways of Titanopodus mendozensis González Riga and Calvo provide information about the locomotion of titanosaurian sauropods that lived in South America during the Late Cretaceous. Titanopodus ichnites were found at Agua del Choique, a newly discovered track site in the Loncoche Formation, Late Campanian-Early Maastrichtian of Mendoza, Argentina. This speed study follows the hypothesis of dynamic similarity proposed by Alexander. As a refinement of this method, a complementary equation is presented here based on an articulated titanosaurian specimen collected in strata that are regarded as correlative to those that have yielded Titanopodus tracks (Allen Formation, Neuquén Basin). This analysis indicates that hip height can be estimated as 4.586 times the length of the pes track in derived titanosaurs. With an estimation of the hip height and the stride measurements, the speed is calculated. The study of two wide-gauge trackways indicates that Titanopodus ichnites were produced by medium-sized titanosaurs (hip height of 211-229 cm) that walked at 4.7-4.9 km/h towards the south and southwest, following, in part, a sinuous pathway. These speeds and some taphonomic features of tracks (prominent rims, distorted elongated shapes)indicate the capacity of derived titanosaurs for walking effectively over a very wet and slippery substrate. In the ichnological record, the walking speeds of Titanopodustrackmakers are somewhat faster than those previously inferred for most sauropods.

Sauropod and theropod dinosaur tracks from the Upper Cretaceous of Mendoza (Argentina): Trackmakers and anatomical evidences

“…Discussion4.1. Trackmackers of sauropod ichnitesIn South America, the only sauropod that lived since the Coniacian age are titanosaurs (e.g.Leanza et al, 2004;González Riga 2011). This is congruent with the ichnological record described in this paper.…”

“…As refinements of previous studies, González Riga (2011) calculated that H is about 4.586 based on an articulated titanosaur specimen from Patagonia , similar in size and age to the Titanopodus trackmaker. For theropod tracks we follow the parameter of Leonardi (1987) and Farlow (1989) (Figure 2 Casanovas et al 1997).…”

March of the Titans: The Locomotor Capabilities of Sauropod Dinosaurs

“…In contrast, bone scaling and biomechanical analysis shows little to distinguish sauropods from other quadrupedal dinosaurs [25]. Ichnological analysis has been used to calculate the speeds of titanosaur trackways [26], [27] but this may only encompasses a subset of possible gaits due to preservational bias [28], and is subject to a number of caveats in terms of accuracy [29].…”

Dynamic Similarity in Titanosaur Sauropods: Ichnological Evidence from the Fumanya Dinosaur Tracksite (Southern Pyrenees)

“…The clade comprises the largest vertebrates that ever walked on land, with adult individuals of some species estimated to have reached up to 30 metres in length [2], [3]. Sauropod locomotion has been a subject of intense research and in the last decades much insight has been gained from studies of ichnology and biomechanics [4]–[9] but very few studies have specifically examined the gaits of titanosaurs [10], [11]. This is surprising given the dominance of this group in Cretaceous faunas and their possession of a suite of anatomical features thought to underpin a shift in locomotor dynamics relative to more basal neosauropods [8], [12], [13].…”