Sauropod Trackway Reflecting an Unusual Walking Pattern from the Early Cretaceous of Shandong Province,China

The trackway of a quadrupedal dinosaur from the Early Cretaceous (Albian) Qingquan tracksite (Tancheng, Shandong Province) is redescribed, and the trackmaker is identified as a sauropod. The trackway makes a slight turn towards the northwest and is characterized by an extremely narrow gauge pattern and an unusual configuration, i.e., a conspicuous difference between the position of the left and right manus tracks with respect to the position of the preceding pes track. Left manus tracks are located on the inside of the trackway, very close (and sometimes even in connection) to the opposite right pes tracks. So far, the Qingquan trackway is possibly the only extremely narrow-gauge sauropod trackway known from China. However, it is not clear to what extent this extremely narrow gauge pattern is related to the turning or a special behavior, or even linked to an injury (“limping trackway”). We tentatively attribute the Qingquan trackway to cf. Parabrontopodus, even though it has a rather low heteropody that is significantly lower than in Parabrontopodus and not typical for narrow-gauge sauropod trackways, but occurs in the wide-gauge ichnotaxon Brontopodus. Because of this discrepancy, the Qingquan trackway cannot readily be attributed to a more basal sauropod, which is generally considered the producer of narrow-gauge trackways. Therefore, the identification of a distinct sauropod group is not possible presently. The only skeletal remains of sauropods from the Lower Cretaceous of Shandong Province belong to the large titanosauriform, Euhelopus zdanskyi.     

Thunder lizard handstands: Manus-only sauropod trackways from the Glen Rose Formation (Lower Cretaceous,Kendall County,Texas)

Abstract

Three parallel, manus-only sauropod trackways from the Coffee Hollow A-Male tracksite (Glen Rose Formation, Kendall County, Texas) were studied separately by researchers from the Heritage Museum of the Texas Hill Country and the Houston Museum of Natural Sciences. Footprint and trackway measurements generally show good agreement between the two groups’ data sets. Footprints appear to be shallowly impressed true tracks rather than undertracks. One of the Coffee Hollow trackways shows marked asymmetry in the lengths of paces that begin with the left as opposed to the right forefoot, and two of the Coffee Hollow trackways are unusually broad. The Coffee Hollow trackways differ enough from the manus portions of other Glen Rose Formation sauropod trackways to suggest that they were made by a different kind of sauropod. Greater differential pressure exerted on the substrate by the forefeet than the hindfeet probably explains the Coffee Hollow trackways, like other manus-only sauropod trackways, but the possibility that they indicate unusual locomotion cannot at present be ruled out.     

A theropod–sauropod track assemblage from the ?Middle–Upper Jurassic Shedian Formation at Shuangbai,Yunnan Province,China, reflecting different sizes of trackmakers: Review and new observations

A dinosaur tracksite at Hemenkou (Shuangbai County, Yunnan Province) in the ?Middle–Upper Jurassic Shedian Formation that consists mainly of gray-purple feldspathic quartz sandstones was previously reported incorrectly as being in the Lower Cretaceous Puchanghe Formation. The previous assignment is also inconsistent with two regional geological maps. Although mostly yielding poorly preserved tracks, the site nevertheless indicates a diversity of theropod and sauropod trackmakers partly consistent with the Late Jurassic body fossils from the region. Purported ornithopod are re-evaluated here as those of theropods. The theropod tracks and trackways show distinct similarities to those of the Grallator–Eubrontes plexus and can be subdivided into three morphotypes that may reflect different pes anatomy and/or substrate conditions. Two sizes of tracks (small, large) indicate the presence of different size classes or species in this area in the Late Jurassic. Similarly, the sauropod trackways document three differently sized trackmakers (small–medium–large) showing a typical wide-gauge (Brontopodus) pattern. The track record is the first evidence of theropods in the ?Middle–Late Jurassic of central Yunnan, whereas the sauropod tracks suggest a relation to the coeval basal eusauropods known from this region by skeletal remains.     

Manus-only titanosaurid trackway from Fumanya (Maastrichtian, Pyrenees): further evidence for an underprint origin

The origin of manus-only and manus dominated sauropod trackways has been a matter of intense debate since two hyphothesis exist: (a) manus-only and manus-dominated trackways result from a 'swimming' sauropod, and (b) they result from a selective underprint phenomenon that only leaves the manus recorded. Several new sauropod trackways are reported in the Fumanya tracksite area (Maastrichtian), in SE Pyrenees, where both tracks and undertracks are found on the same stratigraphic bedding surface. In one of the trackways, footprint morphology together with the trackway pattern displays a clear succession of manus-only impressions attributed to a sauropod dinosaur in a walking gait. The ichnological comparison between the manus-only trackway with the other complete trackway (manus-pes) display an identical distribution of the manus pattern. This fact clearly points towards an underprint phenomenon as the origin for manus-only trackways, since it is rather unlikely that the same pattern would completely match different locomotion behaviours such as walking and swimming. Therefore, we suggest an interpretation based on the differential loading between the hindfoot and the forefoot on an upper stratigraphic track-level, for the studied manus-only trackway. □ Fumanya tracksite, manus-only trackways, titanosaurs, trackway pattern, underprint, Upper Cretaceous.     

A New Pterosaur Tracksite from the Jurassic Summerville Formation,Near Ferron,Utah

Pterosaur tracks (cf. Pteraichnus) from the Summerville Formation of the Ferron area of central Utah add to the growing record of Pteraichnus tracksites in the Late Jurassic Summerville Formation and time-equivalent, or near time-equivalent, deposits. The site is typical in revealing high pterosaur track densities, but low ichnodiversity suggesting congregations or “flocks” of many individuals. Footprint length varies from 2.0 to 7.0 cms. The ratio of well-preserved pes:manus tracks is about 1:3.4. This reflects a bias in favor of preservation of manus tracks due to the greater weight-bearing role of the front limbs, as noted in other pterosaur track assemblages. The sample also reveals a number of well-preserved trackways including one suggestive of pes-only progression that might be associated with take off or landing, and another that shows pronounced lengthening of stride indicating acceleration.

One well-preserved medium-sized theropod trackway (Therangospodus) and other larger theropod track casts (cf. Megalosauripus) are associated with what otherwise appears to be a nearly monospecific pterosaur track assemblage. However, traces of a fifth pes digit suggest some tracks are of rhamphorynchoid rather than pterodactyloid origin, as usually inferred for Pteraichnus. The tracks occur at several horizons in a thin stratigraphic interval of ripple marked sandstones and siltstones. Overall the assemblage is similar to others found in the same time interval in the Western Interior from central and eastern Utah through central and southern Wyoming, Colorado, northeastern Arizona, and western Oklahoma. This vast “Pteraichnus ichnofacies,” with associated saurischian tracks, remains the only ichnological evidence of pre-Cretaceous pterosaurs in North America and sheds important light on the vertebrate ecology of the Summerville Formation and contiguous deposits.     

Trackway Ratio: A New Look at Trackway Gauge in the Analysis of Quadrupedal Dinosaur Trackways and its Implications for Ichnotaxonomy

A new parameter, the Trackway Ratio (TR), is proposed to supplement the previously used trackway gauge to describe and quantify the relative width of trackways in dinosaur quadrupedal gaits. It is expressed as the ratio of the width of the tracks relative to the total width of the trackway (both measured perpendicular to the long axis of the trackway). The ratio may be used with either pes (PTR) or manus (MTR) tracks. The PTR range of values for wide-, medium- and narrow-gauge trackways of previous authors are provisionally suggested to be ≤35%, 36–49% and ≥50%, respectively. The application of such a ratio would permit a more consistent ichnotaxonomy to be adopted where both track morphology and trackway parameters are used to define ichnotaxa.

Determination of the TR, as well as other parameters, will be affected by track preservation quality. Recent experiments on track simulation in the laboratory have shed further light on observations made in the field concerning the value of track measurements (in particular track length and width) recorded from below the surface on which the maker was moving. Experimental track simulations in the laboratory have shown that the dimensions of transmitted tracks preserved below the surface on which the foot was impressed may vary from 65% to 135% of the true dimensions of the indenter. Two case studies are presented that quantify the errors that may be made on calculating TR and the size, gait and speed of the maker, from trackways if the preservation of the tracks are not fully understood.

It is shown that in individual trackways the PTR may vary along the length of the trackway; so that part of the trackway may be classified as wide-gauge and other parts medium-gauge. There is a relationship between variation in PTR and that of pace angulation along the length of a single trackway. An analysis of 42 trackways, principally sauropod, shows a temporal distribution that does not agree closely with previous suggestions relating to narrow- and wide-gauge trackways.     

First dinosaur tracks from the Arabian Peninsula

Background

The evolutionary history of Mesozoic terrestrial vertebrates from the Arabian Peninsula is virtually unknown. Despite vast exposures of rocky outcrops, only a handful of fossils have yet been described from the region. Here we report a multi-taxon dinosaur track assemblage near Madar village, 47 km north of Sana''a, Republic of Yemen. This represents the first dinosaur tracksite from the Arabian Peninsula, and the only multi-taxon dinosaur ichnosite in the Middle East.

Methodology/Findings

Measurements were taken directly from trackway impressions, following standard ichnological conventions. The presence of bipedal trackmakers is evidenced by a long series of pes imprints preserving smoothly rounded posterior margins, no evidence of a hallux, bluntly rounded digit tips and digital divarication angles characteristic of ornithopod dinosaurs. Nearby, eleven parallel quadrupedal trackways document a sauropod herd that included large and small individuals traveling together. Based on the morphology of manus impressions along with a narrow-gauged stance, the quadrupedal trackways were made by non-titanosauriform neosauropods. Additional isolated tracks and trackways of sauropod and ornithopod dinosaurs are preserved nearby.

Conclusions/Significance

Taken together, these discoveries present the most evocative window to date into the evolutionary history of dinosaurs of the Arabian Peninsula. Given the limited Mesozoic terrestrial record from the region, this discovery is of both temporal and geographic significance, and massive exposures of similarly-aged outcrops nearby offer great promise for future discoveries.     

Review and Detailed Description of Sauropod-Dominated Trackways from the Upper Cretaceous Jiangdihe Formation of Yunnan,China

Type specimens of the sauropod ichnotaxon Chuxiongpus changlingensis, which was later reassigned to Brontopodus changlingensis, as well as the theropod ichnotaxon Yunnanpus huangcaoensis, both from the Cretaceous Jiangdihe Formation of Yunnan Province, are redescribed in order to document their morphological features. Both, but particularly Y. huangcaoensis, which is considered now a nomen dubium, were originally based on poorly preserved material. Nevertheless, the specimens document a saurischian dominated biota that existed during the deposition of the Jiangdihe Formation from which no skeletal remains are known. B. changlingensis trackways were left by small sauropods that show consistent partial or complete overprint of the manus by the pes. This pattern makes it difficult to calculate manus length, and heteropody can be only estimated.     

Maastrichtian Sauropod footprints from the Fumanya site,Berguedà, Spain

A sauropod tracksite near Fumanya (Berguedà, Catalunya, Spain) was mapped in detail in 1996. Discovered by Viladrich (1986), this is the only known Maastrichtian sauropod tracksite in Europe. The tracks have been strongly affected by strain and erosion. The wide‐gauged, four‐clawed pes trackways are attributed to titanosaurs. Although most trackways indicate single individuals, a few trackways involved multiple individuals, suggesting social behavior.     

Trackways of the American Crocodile (Crocodylus acutus) in Northwestern Costa Rica: Implications for Crocodylian Ichnology

We documented trackways of free-living Crocodylus acutus on beaches at the mouths of Tamarindo and Ventanas estuaries, Costa Rica. Our crocodiles had estimated total lengths of 1–3 meters or more. Manus prints have five digits, with digits I–III bearing claw marks. Pes prints have four digits, with claw marks on digits I–III. The pes is plantigrade. Claws generally dig into the substrate. Apart from claw marks, digit I and the heel of the pes are usually the most deeply impressed parts of footprints. Trackways are wide-gauge. Pes prints are usually positioned just behind ipsilateral manus prints of the same set and may overlap them. Manus and pes prints angle slightly outward with respect to the crocodile's direction of movement. Claw-bearing digits of both the manus and pes may create curved, concave-toward-the-midline drag marks as the autopodium is protracted. The tail mark varies in depth and clarity, and in shape from nearly linear to markedly sinuous. Sometimes the tail mark hugs the trackway midline, but sometimes it is closer to, or even cuts across, prints of one side. American crocodile footprints and trackways are similar to those observed in other extant crocodylian species, indicating substantial trackway conservatism across the group.     

Sauropod tracks from the Middle Jurassic Chuanjie Formation of Yunnan Province and the pre-Cretaceous sauropodomorph trackways from China

The Xixipo dinosaur tracksite in the Chuanjie Formation of Yunnan Province is one of the 14 Chinese sites yielding sauropod tracks from between the Triassic–Jurassic and Jurassic–Cretaceous boundaries, but is only one of the two that represent the Middle Jurassic. Although it is a small site, it adds incrementally to the overall track record of the region and allows comparison with the body fossil record and classification of the Chuanjie Formation as a Type 3b or Type 4b deposit in which both the body fossil and trace fossil record, in this case representing sauropodomorphs, are similar in composition and frequency of occurrence. We argue that the sauropod trace and body fossil records, while based on different categories of evidence, are very important. Integrating and correlating all available data from both records increases our understanding of sauropod communities, and both are equally valuable for this. In addition, we also discuss narrow to wide gauge, coeval sauropod trackways from China, and the relationship between the potential trackmaker of China's Jurassic Brontopodus-type trackways and mamenchisaurids and, beginning from the Late Jurassic, representatives of this type and titanosauriform sauropods.     

Ethological variations in gauge in sauropod trackways from the Berriasian of Spain

Castanera, D., Pascual, C., Canudo, J.I., Hernández, N. & Barco, J., 2012: Ethological variations in gauge in sauropod trackways from the Berriasian of Spain. Lethaia, Vol. 45, pp. 476–489. Two sauropod trackways from the Early Cretaceous (Berriasian) of the Cameros Basin (Spain) show important variations in trackway gauge, along the same trackway. These variations seem to be associated with different behaviours; on the one hand with a significant variation in the direction of travel (turning phenomena) and on the other hand with a decrease in speed, probably associated with the properties of the substrate. These variations in sauropod trackways provide the trackway gauge debate with new data, supporting the hypothesis that the walking style and substrate properties may in some cases determine this sauropod character. The study of turning sauropod trackways improves our knowledge of sauropod locomotion. □Ethology, intermediate‐gauge, sauropod trackways, substrate properties, wide‐gauge.     

A NEW WIDE-GAUGE SAUROPOD TRACK SITE FROM THE LATE CRETACEOUS OF MENDOZA, NEUQUÉN BASIN, ARGENTINA

Abstract:  Agua del Choique is a new Late Cretaceous sauropod track site from Mendoza Province, Neuquén Basin, Argentina. It is situated in the Loncoche Formation, late Campanian – early Maastrichthian in age, and is one of the youngest sauropod tracks site recorded in the world. Agua del Choique represents a lake setting and river-dominated delta deposits, and comprises at least 160 well-preserved tracks, located on a calcareous sandstone bed. A new ichnotaxon, Titanopodus  mendozensis ichnogen. et ichnosp. nov., is erected for the footprints of this track site. Titanopodus  mendozensis exhibits the following association of features: (1) wide-gauge trackway (manus and pes trackway ratios of 18–22 and 26–31 per cent respectively), (2) pronounced heteropody (manus-pes area ratio of 1:3), (3) outer limits of trackway defined, in some cases, by the manus tracks, and (4) manus impression with an asymmetrical crescent contour and acuminate external border. Titanopodus  mendozensis is an excellent case study of the wide-gauge style of locomotion produced by Late Cretaceous derived titanosaurs that have no impression of manual phalanges. These features, and the fossil record from the Loncoche Formation, suggest that the trackmakers were, probably, middle size saltasaurine or aeolosaurine titanosaurs (14–16 m long).     

Pterosaur tracks and the terrestrial ability of pterosaurs

Unusual tracks of a quadrupedal animal with a three-digit (occasionally four-digit) manus print and four-digit pes print were first interpreted as those of pterosaurs in the 1950s. In the 1980s these tracks were reinterpreted as crocodilian, but new material shows that the original identification was correct. Two features: evidence for elongate penultimate phalanges in digits two to four of the pes, and manus trackways up to three times the width of pes trackways, can only be attributed to pterosaurs. Recent improvements in understanding of pterosaur anatomy and functional morphology explain remaining difficulties regarding the interpretation of ich-nites such as the orientation of the manus digits and the absence of some expected ichnological features. Pteraichnus and Pteraichnus-like tracks show that, when grounded, some, perhaps all, pterosaurs were plantigrade, quadrupedal, and had a semi-erect stance and gait. This is consistent with some functional interpretations of pterosaur anatomy and resolves a long-running debate regarding the terrestrial ability of this group.     

New Ichnotaxa of Mammal and Reptile Tracks from the Upper Paleocene of Alberta

Only two vertebrate trackways are known from the Paleocene of western Canada and are among the few Paleocene vertebrate trackways known worldwide.

A natural cast trackway consisting of five prints (three pes, two manus) on a fallen block was found along the Red Deer River, near the town of Red Deer, Alberta, in 1927. The discoverers, Ralph Rutherford and Loris Russell, identified the strata the track block had fallen from as belonging to the Paskapoo Formation (upper Paleocene: middle Tiffanian). The trackway was attributed to a mammalian track-maker in two subsequent publications. However, the prints are more characteristic of a reptilian (crocodylian) track-maker.

A natural cast track-bearing block was discovered on Signal Hill in the city of Calgary during the preparation of a new residential subdivision in 1990. The large track-bearing block was found in a rock pile but is suspected to have originated from strata belonging to the Porcupine Hills Formation (Upper Paleocene: late Torrejonian), which was being excavated at the time. This large slab contains twelve prints (six pes, six manus) and is associated with extensive mud cracks. The mammalian affinity of the trackmaker was recognized by researchers from the Royal Tyrrell Museum of Palaeontology.     

Thinopus and a Critical Review of Devonian Tetrapod Footprints

Devonian tetrapod tracks and trackways can be recognized by three criteria: morphology of the manus and pes impressions that matches known Devonian tetrapod skeletal morphology, manus smaller than pes, and the alternating trackway pattern that results from lateral sequence walking in quadrupedal tetrapod locomotion. The first reported Devonian tetrapod track, named Thinopus antiquus, from Pennsylvania, is not a tetrapod track and is likely an impression of a fish coprolite(s). A critical review of the published Devonian track record indicates only three can be verified as produced by a tetrapod trackmaker—Genoa River, Australia; Easter Ross, Scotland; and Valentia Island, Ireland. The supposed tetrapod tracks from the Middle Devonian of the Zache?mie quarry, Poland, fail the criteria for identification as Devonian tetrapod tracks. Indeed, no convincing case has been made that the Zache?mie structures are tetrapod tracks. Instead, they are reinterpreted as fish nests/feeding traces (ichnogenus Piscichnus). The oldest Devonian tetrapod trackway is Givetian and this is the oldest record of a tetrapod, but the sparse record of Devonian tetrapod tracks is of no other biostratigraphic and little paleobiogeographic significance. Bona fide Devonian tetrapod tracks are from nonmarine facies, so they do not support a marginal marine origin of tetrapods. They indicate lateral sequence walking and pelvic-limb-propelled, fully terrestrial (subaerial) locomotion in freshwater environments by at least some Devonian tetrapods.     

Las cerradicas tracksite (Berriasian,Galve, Spain): Growing evidence for quadrupedal ornithopods

Dinosaur footprints occur in shallow marine sedimentary units of the Berriasian Villar del Arzobispo Formation in the Aliaga basin, NE Spain. Las Cerradicas is a small outcrop (25 m²), near Galve, with four dinosaur trackways. Three tridactyl trackways indicate bipedal animals, and have parallel orientation. A fourth or‐nithopod trackway indicates a quadrupedal animal and is the smallest among any reported in the literature (L = 23 cm, W = 23 cm of pes tracks). It has manus prints that are oval‐shaped impressions. These and other recent discoveries shed much light on the abundance of quadrupedal ornithopods during the early Cretaceous.     

A Middle Jurassic dinosaur trackway site from Oxfordshire, UK

The Middle Jurassic (Bathonian) Ardley trackway site in Oxfordshire, UK is described in detail. The track site is extensive, containing over 40 more-or-less continuous theropod and sauropod trackways preserved together on a single bedding plane with some trackways up to 180 m in length. The trackways display reasonable preservation, with claw marks discernible. Sauropod trackways are by far the most abundant and are representative of taxa that exhibit both narrow and wide-gauge styles of locomotion. Theropod trackways are represented by large tridactyl prints and claw impressions that display exceptionally low pace angulation values during their walking phase. One theropod trackway is unique in that it reveals a gait transition associated with a temporary increase of speed. These dinosaurs were walking over a lime-mud firmground to hardground that was emergent, or locally very shallowly submerged. GPS (Global Positioning Satellite) data reveal that the tracks, preserved during a short time interval, trend in a north-easterly direction. Multi-herding behaviour is suggested for the sauropods of differing size. The discovery of this site adds significantly to our knowledge of the taxonomic composition of Middle Jurassic ecosystems. Evidence concerning locomotor styles employed by saurischian dinosaurs, footprint identification, potential trackmaker, social interactions and observations concerning estimates of Middle Jurassic faunal diversity, as well as aspects of dinosaur locomotor evolution are discussed.     

Pterosaur Stance and Gait and the Interpretation of Trackways

The tracks ascribed to pterosaurs from the Late Jurassic limestones at Crayssac, France, must be pterosaurian because the manus prints are so far outside those of the pes, the pes print is four times longer than wide, and the manus prints appear to preserve distinct traces of a posteromedially directed wing-finger. These tracks are different in important ways from previously described Pteraichnus trackways, which have been variably considered pterosaurian, crocodilian, or indeterminate. No Pteraichnus (sensu stricto: those not from Crayssac) tracks have diagnostic features of pterosaurs and in none can a complete phalangeal or digital formula be reconstructed; however, all published Pteraichnidae tracks fulfill the criteria of poor preservation, and some have some diagnostic features of crocodile tracks. Reconstructions of pterosaurs walking in pteraichnid tracks do not fit those tracks well, but crocodiles do. In contrast, the Crayssac tracks demonstrate the erect stance and parasagittal gait previously reconstructed for pterosaurs. They also demonstrate that the footfall pattern was not as in typical reptiles (LH-RF-RH-LF), but that the manus must have been raised before the next forward step of the ipselateral foot (LH-LF-RH-RF), suggesting that the quadrupedal pattern was secondary. The metatarsus in pterosaurs was set low at the beginning of a stride, as it is in crocodilians and basal dinosaurs. The diagnosis of the Ichnofamily Pteraichnidae comprises features of possible crocodilian trackmakers, but not of possible pterosaurian trackmakers. Trackways considered for attribution to pterosaurs should show (1) manus prints up to three interpedal widths from midline of body, and always lateral to pes prints, (2) pes prints four times longer than wide at the metatarso-phalangeal joint, and (3) penultimate phalanges longest among those of the pes.     

The dinosaur tracksite of Loulle (early Kimmeridgian; Jura,France)

More than 1500 sauropod and theropod tracks have been discovered and excavated on the floor of a disused 3800 m² quarry, near the village of Loulle (French Jura). These levels correspond to a tidal-flat environment, from intertidal to supratidal zone, dated from the earliest Kimmeridgian (∼157 M.a.). Eighteen sauropod trackways have been recognized, ranging from 3.8 m to 51.5 m in length. These trackways do not correspond to a unique herd passage, because trackways are diversely oriented, most of them are crossing others and prints are more or less deeply marked, depending of different stages of substratum competence. According to the trackway gauges, the three types (narrow-, medium and wide-gauge) are represented. Some trackways could be referred to the ichnogenus Brontopodus Farlow et al., 1989, and others to Parabrontopodus Lockley et al., 1994a. Based on footprint size, the body-sizes of these 18 sauropod trackways range from tiny (Pes Length < 25 cm) to large individuals (PL > 75 cm), showing a regular continuum of sizes. Several biometrical ratios classically used in sauropod ichnology appear to be closely related to size (e.g., the smallest individuals apparently moved faster than the largest; large individuals are all narrow-gauge while small individuals are all wide-gauge; large specimens are characterized by a high heteropody ratio when the smallest show a low heteropody ratio). Associated with these sauropod trackways, four theropod trackways have also been recorded. Three small to medium-sized theropod are referred to the ichnogenus Carmelopodus Lockley et al., 1998a, while a large individual (PL = 77 cm) is tentatively referred to Megalosauripus Lessertisseur, 1955.