Fossil Vertebrate Tracks as Paleopenetrometers: Confounding Effects of Foot Morphology

Falkingham, Peter L.; Margetts, Lee; Manning, Phillip L.

doi:10.2110/palo.2009.p09-164r

Cited by 39 publications

(42 citation statements)

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“…The aim was not to model a specific substrate, but more to create a model in which a continuum of substrate strengths and loading conditions could be simulated. An elasticplastic von Mises stress model was used to represent a clay-or mud-like cohesive substrate [12,13], defined by three parameters: shear strength (Cu), Poisson ratio (v) and Young's modulus (E).…”

Section: Methodsmentioning

confidence: 99%

“…As a consequence, we believe a simple elastic -plastic substrate model offers a bestcase scenario for correlations between pressure and footprint depth, but accept restricting this analysis to cohesive substrates is a limitation in this study. The substrate volume modelled had dimensions of length, width and depth of 1 m, which is equal to approximately 4.5 times foot length in all dimensions to avoid boundary effects [12,13]. The sediment volume was composed of 1 960 400 eightnode hexahedral elements, and in order to reduce element number (and consequently run time) while maintaining a high level of accuracy, a scaling algorithm was used that generated larger elements away from the area loaded beneath the foot.…”

Section: Methodsmentioning

confidence: 99%

“…That the same qualitative disparity between pressure and depth is found in these simulations, regardless of whether pressures are applied uniformly across the foot in a subvertical indentation ( figure 2a,b), or in a non-uniform pattern mimicking treadmill pressures ( figure 2c,d,g,h), strongly suggests that discrete regions of the plantar foot differ in their indentation potential. Falkingham et al [12] demonstrated that indenter shape, specifically the ratio of edge length to surface area, influences penetration depth in compliant media. The mismatch between the relative distribution of pressure and depth in our simulations is consistent with the shape effects described by Falkingham et al [12].…”

Section: Hyp2: Plantar Pressures Versus Beach Footprint Topologymentioning

confidence: 99%

“…Falkingham et al [12] demonstrated that indenter shape, specifically the ratio of edge length to surface area, influences penetration depth in compliant media. The mismatch between the relative distribution of pressure and depth in our simulations is consistent with the shape effects described by Falkingham et al [12]. In cohesive substrates, shapes with relatively less edge length penetrate to greater depths for a given pressure [12].…”

Section: Hyp2: Plantar Pressures Versus Beach Footprint Topologymentioning

confidence: 99%

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Does footprint depth correlate with foot motion and pressure?

Bates

Savage

Pataky

et al. 2013

J. R. Soc. Interface.

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Footprints are the most direct source of evidence about locomotor biomechanics in extinct vertebrates. One of the principal suppositions underpinning biomechanical inferences is that footprint geometry correlates with dynamic foot pressure, which, in turn, is linked with overall limb motion of the trackmaker. In this study, we perform the first quantitative test of this longstanding assumption, using topological statistical analysis of plantar pressures and experimental and computer-simulated footprints. In computer-simulated footprints, the relative distribution of depth differed from the distribution of both peak and pressure impulse in all simulations. Analysis of footprint samples with common loading inputs and similar depths reveals that only shallow footprints lack significant topological differences between depth and pressure distributions. Topological comparison of plantar pressures and experimental beach footprints demonstrates that geometry is highly dependent on overall print depth; deeper footprints are characterized by greater relative forefoot, and particularly toe, depth than shallow footprints. The highlighted difference between 'shallow' and 'deep' footprints clearly emphasizes the need to understand variation in foot mechanics across different degrees of substrate compliance. Overall, our results indicate that extreme caution is required when applying the 'depth equals pressure' paradigm to hominin footprints, and by extension, those of other extant and extinct tetrapods.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Hyp2: Plantar Pressures Versus Beach Footprint Topologymentioning

confidence: 99%

Section: Hyp2: Plantar Pressures Versus Beach Footprint Topologymentioning

confidence: 99%

See 2 more Smart Citations

Does footprint depth correlate with foot motion and pressure?

Bates

Savage

Pataky

et al. 2013

J. R. Soc. Interface.

Self Cite

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“…Despite the fact that the inner width (and then the type) of the trackways can change along the same trackway (Romano et al, 2007;Castanera et al, 2012), this characteristic may have a clear taxonomical implication in narrow-gauge trackways that presumably could not have been produced by titanosaurs. If the tracks of Parede are preserved as undertracks, then the inner width can also change with the depth of preservation (Jackson et al, 2009;Falkingham et al, 2010;Castanera et al, 2012), such that the trackway would have been preserved as if it were narrower. Even considering this option, the narrow width of the trackway of Parede probably would not represent a truly widegauge trackway.…”

Section: Discussionmentioning

confidence: 99%

Dinosaur tracks from the Early Cretaceous of Parede tracksite (Cascais, Portugal): New implications on the sauropod palaeobiology of the Iberian Peninsula

Santos

Callapez

Castanera

et al. 2015

Journal of Iberian Geology

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A recently discovered Early Cretaceous (early late Albian) dinosaur tracksite at Parede beach (Cascais, Portugal) reveals evidence of dinoturbation and at least two sauropod trackways. One of these trackways can be classified as narrow-gauge, which represents unique evidence in the Albian of the Iberian Peninsula and provides for the improvement of knowledge of this kind of trackway and its probable trackmaker, in an age when the sauropod record is scarce. These dinosaur tracks are preserved on the upper surface of a marly limestone bed that belongs to the Galé Formation (Água Doce Member, middle to lower upper Albian). The study of thin-sections of the beds C22/24 and C26 in the Parede section has revealed a microfacies composed of foraminifers, radiolarians, ostracods, corals, bivalves, gastropods, and echinoids in a mainly wackestone texture with biomicritic matrix. These assemblages match with the lithofacies, marine molluscs, echinids, and ichnofossils sampled from the section and indicate a shallow marine, inner shelf palaeoenvironment with a shallowing-upward trend. The biofacies and the sequence analysis are compatible with the early late Albian age attributed to the tracksite. These tracks and the moderate dinoturbation index indicate sauropod activity in this palaeoenvironment. Titanosaurs can be dismissed as possible trackmakers on the basis of the narrow-gauge trackway, and probably by the kidney-shaped manus morphology and the pes-dominated configuration of the trackway. Narrow-gauge sauropod trackways have been positively associated with coastal palaeoenvironments, and the Parede tracksite supports this interpretation. In addition, this tracksite adds new data about the presence of sauropod pes-dominated trackways in cohesive substrates. As the Portuguese Cretaceous sauropod osteological remains are very scarce, the Parede tracksite yields new and relevant evidence of these dinosaurs. Furthermore, the Parede tracksite is the youngest evidence of sauropods in the Portuguese record and some of the rare evidence of sauropods in Europe during the Albian. This discovery enhances the palaeobiological data for the Early Cretaceous Sauropoda of the Iberian Peninsula, where the osteological remains of these dinosaurs are relatively scarce in this region of southwestern Europe. Therefore, this occurrence is also of overall interest due to its impact on Cretaceous Sauropoda palaeobiogeography.Keywords: Sauropod tracks, intertidal palaeoenvironment, Lower Cretaceous, upper Albian, Lusitanian Basin, Portugal Resumen El reciente descubrimiento de huellas de dinosaurios del Cretácico Inferior (inicio del Albiense tardío) en la playa de Parede (Cascais, Portugal) ha revelado evidencias de dinoturbación y al menos dos rastros de saurópodos. Uno de ellos puede clasificarse como estrecho y representa la única evidencia de este tipo de rastros en el Albiense de la Península Ibérica. Estos nuevos datos permiten mejorar el conocimiento tanto de este tipo de rastros como de su posible productor, en una edad en la...

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Pedal Proportions of Poposaurus gracilis: Convergence and Divergence in the Feet of Archosaurs

Farlow

Schachner

Sarrazin

et al. 2014

The Anatomical Record

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The crocodile-line basal suchian Poposaurus gracilis had body proportions suggesting that it was an erect, bipedal form like many dinosaurs, prompting questions of whether its pedal proportions, and the shape of its footprint, would likewise "mimic" those of bipedal dinosaurs. We addressed these questions through a comparison of phalangeal, digital, and metatarsal proportions of Poposaurus with those of extinct and extant crocodileline archosaurs, obligate or facultatively bipedal non-avian dinosaurs, and ground birds of several clades, as well as a comparison of the footprint reconstructed from the foot skeleton of Poposaurus with known early Mesozoic archosaurian ichnotaxa. Bivariate and multivariate analyses of phalangeal and digital dimensions showed numerous instances of convergence in pedal morphology among disparate archosaurian clades. Overall, the foot of Poposaurus is indeed more like that of bipedal dinosaurs than other archosaur groups, but is not exactly like the foot of any particular bipedal dinosaur clade. Poposaurus likely had a digitigrade stance, and its footprint shape could have resembled grallatorid ichnotaxa, unless digit I of the foot of Poposaurus commonly left an impression. Anat Rec, 297:1022Rec, 297: -1046Rec, 297: , 2014. V C 2014 Wiley Periodicals, Inc.Key words: Poposaurus; archosaur pedal morphology; vertebrate ichnologyThe early Mesozoic adaptive radiation of archosaurs produced a diversity of reptilian life forms; these animals were variously large or small; aquatic, terrestrial, or aerial; herbivorous or carnivorous; ponderous or cursorial (Ewer,

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Fossil Vertebrate Tracks as Paleopenetrometers: Confounding Effects of Foot Morphology

Cited by 39 publications

References 46 publications

Does footprint depth correlate with foot motion and pressure?

Does footprint depth correlate with foot motion and pressure?

Dinosaur tracks from the Early Cretaceous of Parede tracksite (Cascais, Portugal): New implications on the sauropod palaeobiology of the Iberian Peninsula

Pedal Proportions of Poposaurus gracilis: Convergence and Divergence in the Feet of Archosaurs

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