Dinosaur Trackways Research Articles

Limping Dinosaurs? Trackway evidence for abnormal gaits

At least nine different dinosaur trackways are known that reveal alternating long and short steps indicative of limping or some other unusual gait. The reasons for such abnormal dinosaur gaits are not clear in most cases, but they may be related to foot injuries, at least in one example. Most abnormal gait patterns have been observed in bipedal dinosaurs, but they have also been noted in the trackways of quadrupedal dinosaurs. Measurements of the trackway of a limping person reveal similar alternating long and short steps, and suggest that short steps precede the emplacement of an injured foot, and that long steps follow. The ratio of short/long step length provides a measure of the degree of limping. In narrow trackways of limping bipeds, stride length is close to 2 x mean step length, and is quite regular regardless of significant differences in the length of consecutive steps. Such regularity in stride length is not always so apparent in the trackways of quadrupeds, where trackways are wider and severa...

Sedimentology, palaeontology, biostratigraphy and correlation of the Late Cretaceous Vilquechico Group of southern Peru

Detailed analysis of the Late Cretaceous Vilquechico Group (formerly Vilquechico Formation) of the Southern Andes allows the recognition of three major sedimentary sequences, defining Lower, Middle and Upper Vilquechico lithologic formations (LVF, MVF and UVF respectively). Some of them (MVF and UVF) include in turn minor sedimentary sequences. In addition to dinosaur trackways, they contain a marine fauna (selachians, actinopterygians, molluscs) in their transgressive basal parts, and lacustrine fossils (charophytes, ostracods, gastropods) in their regressive continental upper parts. Two charophyte biozones characterize the MVF and the UVF respectively. The lithologic and sedimentary features of the major sequences, as well as their palaeontological contents allow large-scale correlations with other Andean series. Such correlations permit us to tentatively ascribe the unfossiliferous LVF to the Coniacian-early Santonian (?) time-span, and the MVF to the Santonian late Campanian interval. The UVF is of latest Campanian-late Maastrichtian age. As a consequence, the assumed correlations between the Vilquechico Group and some of the vertebrate-bearing Andean localities are revised.

Distribution and Significance of Mesozoic Vertebrate Trace Fossils in Dinosaur National Monument

Search for new tracksites has now revealed a total of 25 localities in the older Mesozoic sedimentary rocks of Dinosaur National Monument (DNM). To date, the most productive units have proved to be the Late Triassic Chinle Group and the mainly Early Jurassic Glen Canyon Group in the western part of DNM. In addition several sites, that are an integral part of the overall paleontological picture, have been found just outside the boundaries of DNM. All these sites (and stratigraphic levels) add up to a total of about 45 tracksites in the DNM area. Chinle sites have now yielded dozens of trackways of theropod dinosaurs, ?prosauropod dinosaurs, mammal-like reptiles, ?phytosaurs, aetosaurs, lepidosaurs and tanystropheids, producing one of the most diverse Late Triassic track assemblages known anywhere. The ?prosauropod tracks are the first Late Triassic examples ever reported from the North American continent. The Lower Jurassic has also yielded theropod and prosauropod dinosaur tracks. These tracks are useful for correlation with other Early Mesozoic tracksites around the world and can be used to help construct a series of track zones (or Palichnostratigraphy) for the western United States. The discovery of prosauropod tracks (Pseudotetrasauropus) in the Chinle Group and in the lower part of Glen Canyon Group (Otozoum) points to a much wider distribution of prosauropod tracks in the western United States than previously supposed, and the need for a thorough study of these and similar track types. Further examination of the Jurassic Cannel Formation close to the DNM boundaries, reveals several tracksites that require further study.

North America's largest dinosaur trackway site: Implications for Morrison Formation paleoecology

Little-known exposures of the Upper Jurassic Morrison Formation from the Purgatoire Valley of southeastern Colorado have yielded the world's largest continuously mapped assemblage of dinosaur trackways. Body fossils include plant, invertebrate, and vertebrate remains indicative of predominantly fresh-water conditions. The tracks occur in a lacustrine sequence characterized by (1) shallow-water shales; (2) micritic shoreface limestones with ooids, intraclasts, ripple marks, mud cracks; and (3) minor quartzose sandstone with salt-crystal casts. Analysis of these sedimentary facies suggests that in southeastern Colorado, lakes were larger and longer lived than in other Morrison paleoenvironments. Trackway orientations and footprint-depth contours pinpoint the location of the paleoshoreline at successive levels in the section. Detailed mapping of 1,300 footprints in bed 2 has revealed more than 100 trackways which testify to the activity of both quadrupedal and bipedal dinosaurs. The respective ratio based on trackway counts is ∼40/60. The quadrupedal tracks are attributed to sauropods, and represent the first ever discovered in North America. They also exhibit the first known manus claw impressions and are in need of formal description. More than 90% of the bipedal tridactyl prints lack claw impressions and are tentatively therefore referred to the Ornithopoda, cf. Gypsichnites possibly a Camptosaurus . The small proportion with distinct claw impressions may represent Allosaurus . Resulting estimates of species diversity (∼5) and predator-prey ratio (1:30) are in general agreement with the estimates of other authors based on skeletal remains, and they suggest that the Purgatoire River tracks may accurately reflect the composition of the dinosaur fauna. Distinctive groupings of parallel, non-overlapping trackways suggest gregarious behavior among sauropods and tridactylous forms.

The use of silicones in the preservation of a field site – the Lark Quarry dinosaur trackways

(1984). The use of silicones in the preservation of a field site – the Lark Quarry dinosaur trackways. Studies in Conservation: Vol. 29, Preprints of the Contributions to the Paris Congress, 2-8 September 1984. Adhesives and Consolidants, pp. 87-91.

Conservation of the Lark Quarry Dinosaur Trackway

Conservation of the Lark Quarry Dinosaur Trackway

Speeds and gaits of dinosaurs

The known relationships of speed, gait and body size (derived mainly from mammals) are used to determine the gaits and theoretical maximum speeds of dinosaurs. Speed estimates are made for 62 dinosaurs (representing 51 genera) and are supplemented with information from comparative anatomy and from dinosaur trackways. It is concluded that smaller bipedal dinosaurs were capable of running at speeds up to 35 or 40 km/h. The so-called “ostrich dinosaurs” are credited with maximum speeds less than 60 km/h, and possibly as low as 35 or 40 km/h. Larger bipedal dinosaurs were probably restricted to walking or slow trotting gaits, with maximum speeds in the range 15–20 km/h. Most quadrupedal dinosaurs seem to have been restricted to a walking gait. Stegosaurs and ankylosaurs may have had maximum speeds as low as 6–8 km/h. Sauropods may have attained 12–17 km/h, and some ceratopsians may have been capable of trotting at speeds up to 25 km/h. On a weight-for-weight basis the speeds of dinosaurs are generally lower than those of mammals.

Were some dinosaurs gregarious?

A careful survey of the dinosaur footprints and trackways (identified as Eubrontes, Anchisauripus and Grallator) at the Mt. Tom site north of Holyoke, Massachusetts, and plots of their orientations reveal that an improbable percentage (70%) of the tracks are oriented in a nearparallel course. All but one of these coincident ancient traverses were probably made by the same kind of Triassic dinosaur (the footprints of which are referred to as Eubrontes). Comparable trackway orientation patterns have been reported by Albritton (1942) near Comanche, Texas for an Early Cretaceous dinosaur (iguanodobntid?) and Bird (1941, 1944) cited paralled sauporod trackways of Early Cretaceous age near the Paluxy River in Texas. Probability dictates that these sub-parallel traverses were not independent events and the presence of other deviating trackways at all three sites indicates that the trackmakers probably were not confined in their passage by physical barriers. Furthermore, the coincidental occurrence of such natural barriers at all of the sites mentioned here seems highly improbable. the combinedevidence of the Massachusetts site and the two Texas localities, together with the apparently widespread occurrence of dinosaur trackway lineation, strongly indicates gregarious habits for several different kinds of dinosaurs.