Two new dinosaur tracksites from the Lower Cretaceous Jiaguan Formation of Sichuan Basin,China: specific preservation and ichnotaxonomy

Two new dinosaur tracksites are reported from the Lower Cretaceous Jiaguan Formation in the Sichuan Basin, Qijiang District of Chongqing. These are the Gaoqing-Yongsheng and the Huibu tracksites, which represent the 13th and 14th reports from this formation. The Gaoqing-Yongsheng tracksite reveals the trackway of a large biped (ornithopod) in association with isolated sauropod tracks and large indeterminate undertracks with radial cracks. These features are preserved as natural casts with pebble infillings in a coarse, cross bedded and very thick bedded sandstone sequence. The Huibu tracksite reveals isolated theropod tracks and ornithopod tracks, the latter having a quadripartite, Caririchnium-like morphology, preserved in a thin bedded sandstone sequence with intercalated mudstone.     

Oldest known avian footprints from Australia: Eumeralla Formation (Albian), Dinosaur Cove,Victoria

Two thin‐toed tridactyl tracks in a fluvial sandstone bed of the Eumeralla Formation (Albian) at Dinosaur Cove (Victoria, Australia) were likely made by avian trackmakers, making these the oldest known fossil bird tracks in Australia and the only Early Cretaceous ones from Gondwana. These tracks, which co‐occur on the same surface with a slightly larger nonavian theropod track, are distinguishable by their anisodactyl form, hallux impressions and wide digit II–IV divarication angles. A lengthy hallux impression and other deformational structures associated with one track indicate foot movement consistent with an abrupt stop, suggesting its tracemaker landed after either flight or a hop. The single nonavian theropod track is similar to other tracks described from the Eumeralla Formation at another locality. The avian footprints are larger than most Early Cretaceous avian tracks recorded worldwide, indicating sizeable enantiornithine or ornithurine species in formerly polar environments of Australia. The avian tracks further supplement scant body fossil evidence of Early Cretaceous birds in southern Australia, which includes a furcula from the Wonthaggi Formation. Because of this discovery, Dinosaur Cove, previously known for its vertebrate body fossils, is added to a growing list of Early Cretaceous vertebrate tracksites in southern Australia.     

New Hettangian tracks from the Causses Basin (Lozère,southern France) complement the poor fossil record of earliest Jurassic crocodylomorphs in Europe

A new vertebrate ichnological assemblage is described from the Hettangian Dolomitic Formation of the Causses Basin, at Le Serre (Lozère, southern France). We report tracks that complement the poor fossil record of lowermost Jurassic crocodylomorphs in Europe. Tetradactyl pes and pentadactyl manus imprints form a unique trackway. Traces are ascribed to Batrachopus isp. and they represent the third occurrence of this ichnogenus in European Hettangian geological formations. This is the first report of Batrachopus in Hettangian deposits of the Causses Basin. The tracks share some similarities with Batrachopus deweyi previously described from the Sinemurian of the Causses Basin. Crocodylomorph tracks co-occur with tridactyl dinosaur traces assigned to Dilophosauripus williamsi and Grallator isp. The sedimentology and palaeoichnology of the tracksite indicate that the depositional environment was a tidal to supratidal flat marsh that was emerged periodically. The ichnological assemblage from Le Serre and a synthesis of ichnotaxa co-occurring with Batrachopus in the European lowermost Jurassic tracksites confirm that crocodylomorphs living in marginal-littoral palaeoenvironments were part of theropod-dominated faunas, together with ornithopods but apparently without sauropods.     

The Fossil Record of Vertebrate Tracks in Mexico

The fossil record of vertebrate tracks in Mexico is taxonomically rich and geographically diverse, and ranges in age from Middle Jurassic to Pleistocene and possibly Holocene. Middle Jurassic saurischian dinosaur tracks from Oaxaca represent the oldest record of vertebrate tracks in Mexico. Tracks attributed to Late Jurassic theropods and ornithopods are known from Michoacán. Theropod tracks of supposed Jurassic age are known from Durango. Lower Cretaceous Saurischian and ornithopod tracks are known from southern Puebla. Central Mexico has yielded Late Cretaceous hadrosaurid and sauropod tracks (Puebla), and tracks belonging to Theropoda and Ornithopoda (El Aguaje, Michoacan). In Coahuila several tracksites occur within the Cerro del Pueblo Formation and include tracks of mesoreptiles, pterosaurs, small to large theropods, bipedal and quadrupedal ornithopods, birds and possibly a mammal. A tracksite in the Olmos Formation includes tracks of turtles, crocodilians, medium-sized theropods, small ornithopods, and birds. Bird tracks of supposed Eocene age are known from Sinaloa. Two important Pleistocene ichnofaunas occur in the states of Puebla (Tepexi de Rodríguez) and Jalisco (San Juan de los Lagos), and include tracks of camelids, artiodactyls, small ungulates, elephants, large felids and birds. Pleistocene human tracks occur in Coahuila and Jalisco. Mexico's track record provides important insights into vertebrate diversity, paleoecology, and paleoenvironments. Given the rate of new discoveries since 1998, there is no doubt that new sites await to be found.     

Asianopodus-type footprints from the Hekou Group of Honggu District,Lanzhou City,Gansu, China and the “heel” of large theropod tracks

An increasing number of dinosaur tracksites have been reported from the Cretaceous Hekou Group deposits of the Lanzhou-Minhe Basin in the Gansu Province region. These include small sites such as the Huazhuang tracksite, from the Honggu District reported here, the Zhongpu tracksite with multiple track levels but few well-preserved tracks, other small tracksites currently under investigation, and the large and diverse Liujixia National Dinosaur Geopark site at Yanguoxia, where intensive study is ongoing. Collectively these sites reveal that ichnofaunas in the Hekou Group are widespread and diverse. The Huazhuang tracksite yields a small assemblage of moderately well-preserved theropod tracks assigned to Asianopodus. This is the first report of Asianopodus from the Hekou Group. Huazhuang Asianopodus belongs to the Eubrontes morphotype. The large theropod tracks from Lanzhou-Minhe Basin were left by large theropod trackmakers with the same general foot morphology. The specimens are described in detail and compared with other theropod track morphotypes from the Lower Cretaceous of China and elsewhere. In general, although the metatarsophalangeal pads of some Jurassic Eubrontes-type tracks are aligned with the axis of digit III, this feature appears most common in the Early Cretaceous theropod (Eubrontes-type) tracks.     

Los Cayos Dinosaur Tracksite: An Overview on the Lower Cretaceous Ichno-Diversity of the Cameros Basin (Cornago,La Rioja Province,Spain)

The Los Cayos dinosaur tracksite is located at the eastern sector of the Cameros Basin (Cornago Township, La Rioja province), NE Spain. The sediments consist of interbedded terrigenous siliciclastics and carbonates belonging to the Enciso Group (Early Cretaceous, Aptian in age). The sedimentological and faunal evidence suggests that these sediments were deposited in a low gradient lacustrine environment. Los Cayos constitutes a relatively wide area with at least 6 localities that have yielded dinosaur tracks. More than 2,000 dinosaur tracks have been discovered to date. Medium to large theropod dinosaurs constitute about 95% of the ichnofauna. Ornithopod dinosaur tracks have been reported from only one of the outcrops (Los Cayos D). Los Cayos S has yielded theropod and sauropod tracks. One sauropod trackway shows a narrow-gauge locomotion pattern and a manus print morphology suggesting that the trackmaker was a titanosaurid, or at least a titanosauriform sauropod. Some pterosaur manus impressions, avian-like footprints of small size and possible turtle tracks complete the assemblage of one of the most impressive and best-preserved dinosaur tracksites of the European Lower Cretaceous.     

Early Cretaceous pterosaur tracks from a “buried” dinosaur tracksite in Shandong Province,China

Here we describe the pterosaur and tridactyl dinosaur footprint assemblage from a new tracksite in the Early Cretaceous Qugezhuang Formation near the Wenxiyuan Community in Jimo County-level City, Qingdao City, Shandong Province, East China. The construction of a community building has, since the discovery, covered the majority of tracks, but a few specimens on abandoned building stones constitute the first pterosaur track record in eastern China. The pterosaur tracks are assigned to Pteraichnus isp. and were probably made by a small to medium-sized pterodactyloid. The new pterosaur trackway contributes to the growing database of pterosaurian ichnites in Asia. The Wenxiyuan tridactyl dinosaur tracks are morphologically similar to those of theropods, but they are too poorly preserved to be referred to any particular ichnotaxon.     

Dinosaur Tracks from the Cedar Mountain Formation (Lower Cretaceous), Arches National Park,Utah

The seventh and largest known dinosaur tracksite from the Cedar Mountain Formation is reported from two important stratigraphic levels in the Ruby Ranch Member within the boundaries of Arches National Park. Previous reports of sites with a few isolated tracks are of limited utility in indicating the fauna represented by track makers. The Arches site reveals evidence of several theropod morphotypes, including a possible match for the coelurosaur Nedcolbertia and an apparently didactyl Utahraptor-like dromeosaurid. Sauropod tracks indicate a wide-gauge morphotype (cf. Brontopodus). Ornithischian tracks suggest the presence of an iguandontid-like ornithopod and a large ankylosaur. Dinosaur track diversity is high in comparison with other early Cretaceous vertebrate ichnofaunas, and it correlates well with faunal lists derived from skeletal remains, thus providing a convincing census of the known fauna.     

Unusual deinonychosaurian track morphology (Velociraptorichnus zhangi n. ichnosp.) from the Lower Cretaceous Xiaoba Formation,Sichuan Province,China

A new Lower Cretaceous dinosaur footprint locality named the Mujiaowu tracksite in the Xiaoba Formation, Sichuan Province, has yielded a new assemblage containing the didactyl deinonychosaurian ichnogenus Velociraptorichnus. This is the eleventh report in the global record, the seventh from Asia and the fifth from China. All, except for an isolated report from Europe, occur in Lower Cretaceous deposits. Unlike previous reports of the ichnogenus, the Mujiaowu site has yielded both didactyl Velociraptorichnus tracks and tridactyl tracks which we interpret as a different expression of this same ichnogenus, caused by registration of digit II, either due to special substrate conditions or to less claw retraction. These tridactyl Velociraptorichnus footprints are assigned to the new ichnospecies Velociraptorichnus zhangi. Such tridactyl deinonychosaurid footprint morphology is predictable, but based on current ichnological evidence appears to be the exception rather than the rule.     

Diverse Dinosaur-Dominated Ichnofaunas from the Potomac Group (Lower Cretaceous) Maryland

Until recently fossil footprints were virtually unknown from the Cretaceous of the eastern United States. The discovery of about 300 footprints in iron-rich siliciclastic facies of the Patuxent Formation (Potomac Group) of Aptian age is undoubtedly one of the most significant Early Cretaceous track discoveries since the Paluxy track discoveries in Texas in the 1930s. The Patuxent tracks include theropod, sauropod, ankylosaur and ornithopod dinosaur footprints, pterosaur tracks, and miscellaneous mammal and other vertebrate ichnites that collectively suggest a diversity of about 14 morphotypes. This is about twice the previous maximum estimate for any known Early Cretaceous vertebrate ichnofauna. Among the more distinctive forms are excellent examples of hypsilophodontid tracks and a surprisingly large mammal footprint. A remarkable feature of the Patuxent track assemblage is the high proportion of small tracks indicative of hatchlings, independently verified by the discovery of a hatchling-sized dinosaur. Such evidence suggests the proximity of nest sites. The preservation of such small tracks is very rare in the Cretaceous track record, and indeed throughout most of the Mesozoic.

This unusual preservation not only provides us with a window into a diverse Early Cretaceous ecosystem, but it also suggests the potential of such facies to provide ichnological bonanzas. A remarkable feature of the assemblage is that it consists largely of reworked nodules and clasts that may have previously been reworked within the Patuxent Formation. Such unusual contexts of preservation should provide intriguing research opportunities for sedimentologists interested in the diagenesis and taphonomy of a unique track-bearing facies.     

Dinosaur footprints from the Early Jurassic of Le Mazel (Lozère,Southern France)

During the 20^th century, the first dinosaur tracks of the Causses Basin were identified at Saint-Laurent-de-Trèves, in the Parc National des Cévennes (southern France). A recent excavation reveals a new theropod tracksite in the Hettangian deposits from Le Mazel, 2 km from the historical tracksite at Saint-Laurent-de-Trèves. The tracks are here described combining a biometric approach and 3D imaging photogrammetry. The main track-bearing surface bears 64 in situ tridactyl footprints preserved as concave epireliefs. Two morphotypes were identified, a “Grallatorid” morphotype and a “Kayentapus” morphotype. Footprints belonging to the first morphotype are closely similar to Grallator lescurei, Grallator minusculus, and Grallator sauclierensis. This study shows the difficulty to distinguish quite similar tridactyl tracks from an ichnotaxonomic point of view and highlights the importance of detailed biometric comparisons. Tracks are preserved in a brown to yellowish dolomudstone showing abundant cryptalgal laminites and mud cracks. These deposits were accrued in shallow environments such as intertidal and supratidal zones of a tidal flat.     

A Diverse Dinosaur-Bird Footprint Assemblage from the Lance Formation,Upper Cretaceous,Eastern Wyoming: Implications for Ichnotaxonomy

A diverse assemblage of dinosaur and bird tracks from Niobrara County, Wyoming, represents the first vertebrate ichnofauna reported from the bone-rich Lance Formation (Maastrichtian, Upper Cretaceous). The ichnofauna includes a hadrosaur track with skin impressions; three theropod track types, including the tetradactyl track Saurexallopus zerbsti (ichnosp. nov.); a tridactyl dinosaur footprint with a fusiform digit III; possible Tyrannosaurus tracks; four distinctive avian ichnites; and invertebrate traces. The footprints are generally well-preserved and so offer a unique insight into the ecology of a small river valley during the Maastrichtian.

Saurexallopus zerbsti ichnosp. nov. from the Lance is similar to Saurexallopus lovei recently reported from the Maastrichtian, Harebell Formation, of northwestern Wyoming, but is represented by much better material, facilitating amendment of the ichnogenus. Skeletal equivalents for Saurexallopus are not currently known. Similarly, the tridactyl track with fusiform digit III is similar to footprints reported from the coeval Laramie Formation of Colorado and may also be similar to ichnogenus Ornithomimipus from the Edmonton Group of Alberta (though not necessarily of ornithomimid affinity). The hadrosaurian track with the skin impression is reminiscent of a similar ichnite reported from the Maastrichtian, St. Mary River Formation in Alberta, which is herein named Hadrosauropodus langstoni as part of a reassessment of Cretaceous ornithopod track ichnotaxonomy. Such correlations demonstrate the utility of tracks for local or regional biostratigraphy (palichnostratigraphy) in western North America. It is also clear that tracks add to our knowledge of the composition and distribution of dinosaurian and avian components of Maastrichtian faunas. In particular the bird tracks indicate a diversity of at least four species, one of which was a semi-palmate form, hitherto unknown in the ichnological record and named Sarjeantichnus semipalmatus.     

Aptian dinosaur footprints from the Apulian platform (Bisceglie,Southern Italy) in the framework of periadriatic ichnosites

New dinosaur tracks have been found near Bisceglie (Bari, Apulia), on loose blocks ascribed to the Corato Member (late Bedoulian to early Gargasian) of the Calcare di Bari Fm. The material consists of isolated footprints as well as of short trackways of quadrupedal and bipedal dinosaurs. The new tracksite has yielded a quite differentiated dinosaur ichnocoenosis, including theropod, sauropod, thyreophoran and ornithopod footprints.The discovery of early Aptian dinosaur footprints in the limestone of the carbonate platform of southern Italy gives new insights on dinosaur distribution, and new palaeontological constraints for the palaeogeographic reconstruction of the Mediterranean Tethys during the Cretaceous. The analysis of this and others ichnosites of the periadriatic carbonate platforms, gives evidence of repeated emersions and of widespread land-vertebrates dwelling. The characteristics of the associations suggest that the trackmakers did not constitute a real coevolved association but the occasional co-occurrence of taxa after migration.The results emphasize the need of both structural and environmental continuity and walking ways between a southern continent and the periadriatic carbonate platforms during the Early Cretaceous.     

Complex In-Substrate Dinosaur (Sauropoda,Ornithopoda) Foot Pathways Revealed by Deep Natural Track Casts from the Lower Cretaceous Xiagou and Zhonggou Formations,Gansu Province,China

Several new Early Cretaceous tracksites from the Lower Cretaceous Xiagou Formation of Gansu Province (China) with tracks of large sauropods and ornithopods are described. Previously reported bird tracks were missing due to human negligence. The studied specimens are preserved as impressions and shallow and deep natural track casts. These dinosaur tracks are first reported from the Jiuquan area in the Changma Basin, matching well with the skeletal record of diverse non-avian dinosaur-bird faunas of this region. Moreover, they add new data to the dinosaur ichnofaunas of the Lanzhou-Minhe Basin (Gansu Province) and indicate a wide distribution of dinosaur-bird assemblages in the Early Cretaceous. Regarding morphology, sauropod, and ornithopod tracks from the Lanzhou-Minhe Basin and the Jiuquan area are very similar to each other. Titanosauriform trackmakers are assumed for the sauropod tracks and possibly iguanodontids have left the large, tridactyl ornithopod tracks. Of particular interest are well-preserved, deep natural track casts of large ornithopods and sauropods preserving ridges and grooves as well as striation marks on the lateral sides of the casts that allow the reconstruction of complex pathways of the foot within the substrate. One particular sauropod pes–manus track cast even indicates lateral and vertical sliding within the sediment because of the presence of “double impressions of digits” on the bottom.     

安徽省黄山地区恐龙(足迹)脚印化石的初步研究

简要报道了安徽省黄山地区所发现的恐龙足迹化石。从脚印的形态和足迹上看,至少有三种不同的恐龙（蜥脚类、兽脚类、鸟脚类）共同生存过,其中多数恐龙为两足行走性的。记述了两个典型的小型兽脚类和小型鸟脚类恐龙所留下的脚印化石。黄山地区恐龙足迹、骨骼化石及其蛋化石的发现,对于研究晚白垩世恐龙生活习性以及古气候环境均有着一定的意义。     

New dinosaur tracksites from the Middle Jurassic of Madagascar: ichnotaxonomical,behavioural and palaeoenvironmental implications

Abstract: New dinosaur tracksites are described from the Bajocian–Bathonian Bemaraha Formation of western Madagascar. Two track‐bearing surfaces can be followed over a distance of at least 4 km, suggesting the existence of a hitherto unrecognized megatracksite. The track assemblage is theropod dominated, but sauropod tracks also occur at one site. Qualitative and quantitative analysis of the abundant theropod track material suggests that most, if not all, theropod footprints are attributable to a single trackmaker and are referred to Kayentapus isp. Although this ichnogenus, originally described from the Lower Jurassic of North America, has never been recorded from Gondwana nor from the Middle Jurassic, track morphology strongly suggests this attribution. Palaeogeographical, sedimentological and ichnological data suggest that the dinosaur tracks formed in an intertidal to supratidal setting where the coastline influenced the preferred walking direction of the animals.     

Palaeoenvironments of vertebrates on the southern shore of Tethys: The nonmarine Early Cretaceous of Tunisia

Through the Late Jurassic and Early Cretaceous, the southern shore of the Tethys Ocean migrated north and south over short distances. These vicissitudes are documented in the ‘continental intercalaire’, a long series of mainly non-marine sediments deposited across North Africa. A combined taxonomic, physical and chemical taphonomic study provides independent lines of evidence for reconstruction of palaeoenvironments within this marginal marine setting.The Douiret, Chenini and Oum ed Diab formations from the Tataouine basin of southern Tunisia span the later part of the Early Cretaceous. Microvertebrates from four sites in these formations show different modes of physical abrasion, time averaging, and mixing, based on a taphonomic analysis using a combination of physical and chemical methods. The taxonomic composition of each assemblage, and trends in rare earth element (REE) compositions of bones, from each locality were used as independent lines of evidence to indicate differences in early depositional environments. The Jebel Boulouha assemblage (Douiret Formation) is interpreted as a terrestrial carbonate-rich environment with relatively little mixing. The Touil el Mra assemblage (Oum ed Diab Formation) suggests a marginal marine environment with some mixing of previously interred bones. The Oued el Khil assemblage (Chenini Formation) and the Oum ed Diab assemblage (Oum Ed Diab Formation) are more equivocal, suggesting mixed freshwater and marine influences. Interpreting salinity in marginal marine settings is difficult, and best attempted from multiple, independent lines of evidence. We suggest that REE geochemistry can contribute to palaeoenvironmental reconstruction when used in combination with other, independent physical, palaeontological and /or geochemical methods.     

New localities of Late Eocene vertebrate footprints from the Tarom Mountains,Northwestern Iran

We document Late Eocene vertebrate footprints from the Tarom Mountains of Iran that represent a significant addition to the record of proboscidean and perissodactyl footprints. These footprints are from sandstones and tuffaceous sandstones of strata equivalent to the Kond Formation that overlie middle Eocene sedimentary rocks and are overlain by Oligocene volcanics. The footprints are preserved at 16 tracksites from 10 distinct stratigraphic levels. The mammal footprints include the oldest known proboscidean tracks, assigned to Proboscipeda enigmatica Panin & Avram and to cf. Proboscipeda isp. Evident perissodactyl tracks are common, tridactyl footprints with distinct digit shapes and proportions assigned to the new ichnogenus and ichnospecies Moropopus elongatus. Footprints of small, hopping, rodent-like mammals are identified as Musaltipes taromi new ichnospecies. Other mammal footprints from the Tarom tracksites are indeterminate, and bird footprints are assigned to Avipeda isp. The Tarom tracksites document the oldest record of proboscidean footprints, and this indicates that proboscideans had reached the northern shore of Tethys by Late Eocene time. The abundance and distinctiveness of the Tarom perissodactyl tracks mirrors the abundance and diversity of moropomorph perissodactyls during the Middle-Late Eocene. The Tarom tracksites are the most extensive record of Eocene vertebrate footprints known from Iran.

http://zoobank.org/urn:lsid:zoobank.org:pub:F430F9DB-728F-4162-9791-DC2A5CC5ED43     

Sauropod and Small Theropod Tracks from the Lower Jurassic Ziliujing Formation of Zigong City,Sichuan, China,with an Overview of Triassic–Jurassic Dinosaur Fossils and Footprints of the Sichuan Basin

A dinosaur footprint assemblage from the Lower Jurassic Ziliujing Formation of Zigong City, Sichuan, China, comprises about 300 tracks of small tridactyl theropods and large sauropods preserved as concave epireliefs (natural molds). The theropod footprints show similarities with both the ichnogenera Grallator and Jialingpus. Three different morphotypes are present, probably related to different substrate conditions and extramorphological variation. A peculiar preservational feature in a morphotype that reflects a gracile trackmaker with extremely slender digits, is the presence of a convex epirelief that occurs at the bottom of the concave digit impressions. It is possibly the result of sediment compaction underweight load when the pes penetrated the substrate, being a resistant residue during exhumation and weathering. The sauropod tracks belong to a trackway with eight imprints consisting of poorly preserved pes and manus tracks and a better preserved set, probably all undertracks. The narrow-gauge trackway pattern resembles the ichnogenus Parabrontopodus well known from the Jurassic but other features such as the minor heteropody are different. The assemblage enriches the dinosaur record from the famous Zigong locality and the evidence from the Lower Jurassic in this area that was restricted to a few skeletal remains and footprints. Furthermore it proves the presence of small theropods, whereas skeletons of the group, well- known from the Middle-Upper Jurassic of Zigong, are of medium to large size only. Remarkable is the dominance of saurischians in these assemblages, which is characteristic of Jurassic dinosaur communities whereas the Cretaceous record shows an increase of ornithopod groups. An overview of the dinosaur trace and body fossil record of the Sichuan Basin supports this view. The paleoenvironment can be designated as a low-latitude tropical freshwater lake as it is indicated by bivalve shells.